Discussion:
drive belt for 7x12 NOT OEM
(too old to reply)
Gene Heskett
2016-05-31 01:14:25 UTC
Permalink
Hi all;

For want of a better project to keep me out of the bars tonight, I went
out and extracted the stripped belt off the toy lathe just now, find it
well labeled as a 130XL037, 3/8" wide, 65 tooth belt. It appears that I
had already replaced the ultra teeny drive pulley that stripped the last
belt easily had already been replaced with a 15 tooth model. So even
with about 7 cogs fully engaged, this motor still had the cojones to
strip the teeth off the belt. So I am thinking out ordering a 140 or
even a 150 (75 cogs) belt and a bigger lower drive pulley which should
get more cogs engaged. That will of course raise the spindle speed and
probably make me run on low backgear more often, but this motor has the
cojones to do that so I am not worried too much.

So my question is, if I buy a 150 cog belt, and the existing lower pulley
has 16 cogs now, and I add 10 more to the belt, making it 75 it sounds
as if I would need to add another 5 to the almost half circle that would
be engaging the belt on each side, so the 16 cog pulley now would turn
into a 26 if I want the center to center distance to remain within say
2mm's of what it is now. That seems to me like if I tension it to about
high C, that ought to be able to survive that 1 hp motor long enough to
at least finish one job, bearing in mind there is a 3/1 stepdown between
the motor, and the shaft turning this lower pulley.

Is my math somewhere near correct? And would I be better off paying the
price of one of the white poly/kevlar belts as opposed to this black one
with a few strabds of kevlar in the backing and teeth that look like a
glass reenforced black rubber? I'll check McMaster-Carr, but I can get
this belt for about $4/copy from the prople that used to be GoodYear.

Comments anybody? Or did my mental math blow it, like its been known to
do several times before?

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Chris Albertson
2016-05-31 03:09:23 UTC
Permalink
Eventually something will again jam in the lathe and stop the spindle
again. When that happens what part would you prefer to break? I'm
guessing you'd prefer a broken $4 belt to a broken gear or burned out
driver electronics. I would not make the belt so strong that the
next strongest part is expensive
--
Chris Albertson
Redondo Beach, California
Gene Heskett
2016-05-31 04:11:58 UTC
Permalink
Post by Chris Albertson
Eventually something will again jam in the lathe and stop the spindle
again. When that happens what part would you prefer to break? I'm
guessing you'd prefer a broken $4 belt
Good point, but belt isn't a quick change item. An hour or so I'd guess.
Post by Chris Albertson
to a broken gear
That might be a stripped key= new shaft and pulley I expect. And way
more than an hour.
Post by Chris Albertson
or burned out
driver electronics.
That is one of Jon's (Pico Systems) PWM-Servo amps, at full rated 9.5
amps of power to that motor, it has enough left over to drive another
just like it. The PSU's don't but thats my problem, I built them.
Either psu would begin to heat its iron at about 1.5kw CCS loading.
Probably 2.5kw ICAS for half an hour or so.

I have two of those servo amps I am driving 1 hp rated PMDC spindles with
& would say that if they are properly configured for current limit, are
safe at least until you want to try to see if they are bulletproof with
real bullets from a deer rifle. Anything else, just bring it on.
Post by Chris Albertson
I would not make the belt so strong that the
next strongest part is expensive
Still a good point but I believe the rest of the drive stuff could handle
50% more delivered torque to the chuck, considering that adding cogs to
the lower pulley would reduce the pull on the belt as the pulley radius
rises, and put more cogs in contact with the belt at the same time. It
would also be a good excuse to make a new countershaft that is a full
1/2" at the lower pulley's hub, strengthening that considerably from its
current 10mm diameter. The rest of the plastic headstock gearset is now
metal too.

I haven't ordered anything yet, I looked at the white si rubber belt on
the M-Carr site, but I can buy 5 of the kevlar backed neoprene ones for
the price of one of those.

But that doesn't answer how much bigger I need to make the lower pulley
in terms of its cog count if I get the 75 cog belt instead of the 65 cog
belt.

If I added 10 cogs to the belt, how many more cogs do I add to the lower
pulley to maintain the current center to center spacing?

Thanks Chris.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
MC Cason
2016-05-31 04:46:40 UTC
Permalink
Gene,
Post by Gene Heskett
Post by Chris Albertson
I would not make the belt so strong that the
next strongest part is expensive
snip
Post by Gene Heskett
Still a good point but I believe the rest of the drive stuff could handle
50% more delivered torque to the chuck, considering that adding cogs to
the lower pulley would reduce the pull on the belt as the pulley radius
rises, and put more cogs in contact with the belt at the same time. It
would also be a good excuse to make a new countershaft that is a full
1/2" at the lower pulley's hub, strengthening that considerably from its
current 10mm diameter. The rest of the plastic headstock gearset is now
metal too.
I haven't ordered anything yet, I looked at the white si rubber belt on
the M-Carr site, but I can buy 5 of the kevlar backed neoprene ones for
the price of one of those.
But that doesn't answer how much bigger I need to make the lower pulley
in terms of its cog count if I get the 75 cog belt instead of the 65 cog
belt.
If I added 10 cogs to the belt, how many more cogs do I add to the lower
pulley to maintain the current center to center spacing?
Thanks Chris.
Cheers, Gene Heskett
I probably missed it somewhere, but what is your center distance, and
the pitch of the pulleys that you have now?

This is a calculator that I have used to play around with different
belt/pulley combinations to fit within the center distance measurements
on a rotary table I'm modding:
https://sdp-si.com/eStore/CenterDistanceDesigner

Move your motor to it's limits in, and out, and measure it's center
distances. Then pick a point somewhere in the middle, and adjust the
numbers on the page, until the belt and pulleys fall within reasonable
sizes.
--
MC Cason
Eagle3D - Created by Matthias Weißer
github.com/mcason/Eagle3D
Gene Heskett
2016-05-31 06:16:09 UTC
Permalink
Post by MC Cason
Gene,
Post by Gene Heskett
Post by Chris Albertson
I would not make the belt so strong that the
next strongest part is expensive
snip
Post by Gene Heskett
Still a good point but I believe the rest of the drive stuff could
handle 50% more delivered torque to the chuck, considering that
adding cogs to the lower pulley would reduce the pull on the belt as
the pulley radius rises, and put more cogs in contact with the belt
at the same time. It would also be a good excuse to make a new
countershaft that is a full 1/2" at the lower pulley's hub,
strengthening that considerably from its current 10mm diameter. The
rest of the plastic headstock gearset is now metal too.
I haven't ordered anything yet, I looked at the white si rubber belt
on the M-Carr site, but I can buy 5 of the kevlar backed neoprene
ones for the price of one of those.
But that doesn't answer how much bigger I need to make the lower
pulley in terms of its cog count if I get the 75 cog belt instead of
the 65 cog belt.
If I added 10 cogs to the belt, how many more cogs do I add to the
lower pulley to maintain the current center to center spacing?
Thanks Chris.
Cheers, Gene Heskett
I probably missed it somewhere, but what is your center distance,
and the pitch of the pulleys that you have now?
This is a calculator that I have used to play around with different
belt/pulley combinations to fit within the center distance
https://sdp-si.com/eStore/CenterDistanceDesigner
Move your motor to it's limits in, and out, and measure it's center
distances. Then pick a point somewhere in the middle, and adjust the
numbers on the page, until the belt and pulleys fall within reasonable
sizes.
Thats the page I couldn't remember and aparently hadn't bookmarked, thank
you.

I don't know as I can get a good accurate center to center, too much
stuff in the way to set a divider points and measure that, and not
enough space beyond either end to get a dial caliper to it. But I'll
mess with it later today & see how good a swag I can come up with. ATM,
and assuming 4.0" C-C only 7 teeth are engaged on the small pulley, and
raising it to 26 brings the 2/1 gear ratio down to 1.2 something with 12
teeth engaged. That should be a huge help. But I'll have to count teeth
on the headstock pulley, I probably don't have it correct.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Chris Albertson
2016-05-31 15:23:55 UTC
Permalink
Post by Gene Heskett
If I added 10 cogs to the belt, how many more cogs do I add to the
lower pulley to maintain the current center to center spacing?
If the two cogs remain roughly the same size then you'd add 20 cogs.
the belt is in contact with 1/2 of the teeth on the cog.

In the special case where the two timing belt cogs are the same size
the belt size equals 2x the center to center distance plus the
circumference of one cog.

Going from 65 to 75 teeth means, I think the new cog needs to have 20
more teeth. As I assume the center to center distance will not change

If the two cogs are not close to the same diameter then you need to
give more information, the center to center distance and the pitch and
size of each cog. I believe there is an on-line calculator some
place. But for same size pulleys you can do it in your head.
--
Chris Albertson
Redondo Beach, California
Gregg Eshelman
2016-05-31 05:19:54 UTC
Permalink
Replace both cogs and the belt with the stronger GT style, and also choose a wider belt. (Nevermind that I went with XL on my 9x20 leadscrew drive mainly because I already had a 22 tooth cog that fit the motor, and found a dirt cheap 44 tooth cog on jet.com )

Somewhere on the web are calculators where you plug in the belt style, center distance and drive ratio then it spits out belts and pulleys that will fit (or at least come close) to what will fit.
For my leadscrew drive I had the center distance a bit off at 77mm. Thought I was going to need an idler (no prob since I have a couple of small XL pulleys) but the fit ended up perfect, have to install both pulleys and belt simultaneously.

Of course I planned it that way...


From: Gene Heskett <***@shentel.net>
To: emc-***@lists.sourceforge.net
Sent: Monday, May 30, 2016 7:14 PM
Subject: [Emc-users] drive belt for 7x12 NOT OEM

Hi all;

For want of a better project to keep me out of the bars tonight, I went
out and extracted the stripped belt off the toy lathe just now, find it
well labeled as a 130XL037, 3/8" wide, 65 tooth belt.  It appears that I
had already replaced the ultra teeny drive pulley that stripped the last
belt easily had already been replaced with a 15 tooth model.  So even
with about 7 cogs fully engaged, this motor still had the cojones to
strip the teeth off the belt.
Gene Heskett
2016-05-31 11:54:55 UTC
Permalink
Post by Gregg Eshelman
Replace both cogs and the belt with the stronger GT style, and also
choose a wider belt. (Nevermind that I went with XL on my 9x20
leadscrew drive mainly because I already had a 22 tooth cog that fit
the motor, and found a dirt cheap 44 tooth cog on jet.com )
Somewhere on the web are calculators where you plug in the belt style,
center distance and drive ratio then it spits out belts and pulleys
that will fit (or at least come close) to what will fit.
Working it sort of bass ackwards, the spacing has to be in the 4.0"
territory for a 16 to 32 tooth XL drive to use a 65 tooth belt. I can't
up the size of the upper pulley as theres no clearance for an increase
between it and the spindle itself. I was surprised to see the belt only
go to 70 from 65 by just changing the lower pulley from 16 to 26, which
put 5 more cogs in mesh on the lower pulley, going from 7 to 12. Since
I can source those pulleys from fleabay for under a tenner a copy, I'll
get a 5 pack of the 140XL037 belts and a 3 pack of the pulleys since
I'll have to bore to suit, and make a fresh countershaft out of
some .500" A2 rod I bought for this in the first place several years
ago. I've nearly 3 feet of it left. The 3 pack of pulleys is so I can
pick the one with the least runout. fleabay pulley's are a bit famous
around here for excess runout, I have one of the 16 toothers laying
around thats about 1/16th inch off center. Timing belts do NOT well
tolerate that.
Post by Gregg Eshelman
For my
leadscrew drive I had the center distance a bit off at 77mm. Thought I
was going to need an idler (no prob since I have a couple of small XL
pulleys) but the fit ended up perfect, have to install both pulleys
and belt simultaneously.
Of course I planned it that way...
Sure you did. ;-) Ya just gotta luv it when a plan works better than
planned. And if you've got papered (EE) frogs watching & telling you it
will never work, but it is when you step back, the grin is even bigger.
BTDT.
Post by Gregg Eshelman
Sent: Monday, May 30, 2016 7:14 PM
Subject: [Emc-users] drive belt for 7x12 NOT OEM
Hi all;
For want of a better project to keep me out of the bars tonight, I
went out and extracted the stripped belt off the toy lathe just now,
find it well labeled as a 130XL037, 3/8" wide, 65 tooth belt.  It
appears that I had already replaced the ultra teeny drive pulley that
stripped the last belt easily had already been replaced with a 15
tooth model.  So even with about 7 cogs fully engaged, this motor
still had the cojones to strip the teeth off the belt.
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Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
andy pugh
2016-05-31 12:16:24 UTC
Permalink
Post by Gene Heskett
I'll
get a 5 pack of the 140XL037 belts and a 3 pack of the pulleys since
I'll have to bore to suit, and make a fresh countershaft out of
some .500" A2 rod I bought for this in the first place several years
ago. I've nearly 3 feet of it left. The 3 pack of pulleys is so I can
pick the one with the least runout.
If you are boring to suit, surely you can correct the runout?
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-05-31 13:12:10 UTC
Permalink
Post by andy pugh
Post by Gene Heskett
I'll
get a 5 pack of the 140XL037 belts and a 3 pack of the pulleys since
I'll have to bore to suit, and make a fresh countershaft out of
some .500" A2 rod I bought for this in the first place several years
ago. I've nearly 3 feet of it left. The 3 pack of pulleys is so I
can pick the one with the least runout.
If you are boring to suit, surely you can correct the runout?
I might have to make a special contacting gauge for that, but I should be
able to hold it to a thou once I've written the matching centerfinder
code. A variation on a routine already used to register a double sided
pcb. But I'll have to make the spinning contact to reach around the
flanges while its turning about 50 rpm's so it touches the top of the
cogs. Might be fun! Particularly if the #@&% pulley's are alu because a
5 volt signal will have a hard time getting thru the oxide.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
andy pugh
2016-05-31 13:20:08 UTC
Permalink
Post by Gene Heskett
Post by andy pugh
If you are boring to suit, surely you can correct the runout?
I might have to make a special contacting gauge for that,
I confess that for this job I just choose to trust my 3-jaw chuck.
So, I turn up a split ring to fit over the pulley teeth and fill out
the radius to the tops of the flanges, then hold it in the 3-jaw and
bore the centre hole.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-05-31 13:47:29 UTC
Permalink
Post by andy pugh
Post by Gene Heskett
Post by andy pugh
If you are boring to suit, surely you can correct the runout?
I might have to make a special contacting gauge for that,
I confess that for this job I just choose to trust my 3-jaw chuck.
So, I turn up a split ring to fit over the pulley teeth and fill out
the radius to the tops of the flanges, then hold it in the 3-jaw and
bore the centre hole.
1. I don't have a lathe to fix the lathe. Not to mention my 3 jaw is
sloppy as hell. I've even ground it while spinning but the scroll is so
poorly cut that half a turn of the wrench and its AFU by 10 thou.

2. So this bore job will have to be done by the mill using a g2 or g3
cycle. And a fresh 1/4" mill. And I'll have to study up on shrink
fits. I want this one tight enough it will take a hacksaw slot all the
way to the shaft to remove it. A torch on the pulley, and the shaft
frozen by dry ice kind of a fit.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
andy pugh
2016-05-31 14:32:26 UTC
Permalink
Post by Gene Heskett
2. So this bore job will have to be done by the mill using a g2 or g3
cycle. And a fresh 1/4" mill. And I'll have to study up on shrink
fits. I want this one tight enough it will take a hacksaw slot
I was going to suggest keyless bushings:
http://www.mcmaster.com/#keyless-bushings/=12nf3l7
But at that price, perhaps not.

They are very good, though.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-06-01 01:32:19 UTC
Permalink
Post by andy pugh
Post by Gene Heskett
2. So this bore job will have to be done by the mill using a g2 or
g3 cycle. And a fresh 1/4" mill. And I'll have to study up on
shrink fits. I want this one tight enough it will take a hacksaw
slot
http://www.mcmaster.com/#keyless-bushings/=12nf3l7
But at that price, perhaps not.
Yes, pricey to be sure. I'd love to have the flush mount on the right
side of the page, but they don't make one small enough. But it does
give me an idea because theres nothing to prevent me from using smaller
screws. There's nothing preventing me from boring it tapered and making
another, smaller than I did for the z motors gear, miniature taperlock
hub, perhaps with a dozen holes alternating threaded and clearance,
doubling the three bolts normally used for a taperlock to 6 smaller
bolts. A 3mm.5 times 6 should be able to get a non-slip grip on a half
inch shaft. I ordered 2 pulleys, and I can bore the first one to fit the
existing shaft, and use it to bore the 2nd pulley and make the hub. I do
have room in front of it, enough to clear the screws heads if the flange
is thin enough. And the hub length is such that a teeny taperlock
wouldn't reach all the way thru it, so I could make the tapered insert
shorter. I'd have about 1/3" inch of alu around it, which should be
sufficient to hold the tapers wedgeing forces and give me plenty of room
for 6 of the 3mm.5 cap screws. I've a whole box of them 12mm long.

But I just got a swag measurment on the C-C distance, and its about .2"
longer than I got using the calculator, so I need to go find that page
again and double-check the figures. I have enough room to move a bit,
but I have to keep the shaft level too. Found it, and counted teeth on
the upper pulley & got 30, I was thinking 32, so the belts I ordered
will be a cog short, but I believe I can move the countershaft that
much. I need to find a hex head metric bolt to use for a spacing
jackscrew, whats in there now is a round head phillips and the only way
to tighten it is grab the edge of the head with a suture clamp. And
since I destroyed the belt, its obvious it was not tight enough if it
allowed the cogs to climb out of the teeth in the pulley. Perhaps I
could remove it and make flats to grab with a 5mm metric wrench. TBD
obviously.
Post by andy pugh
They are very good, though.
At $55 & change for either of the two I could use, they'd better be. But
I believe I can make the taperlock myself, I already have 2 I made in
the Z drive, a 40 tooth on the motor, and an 80 tooth on the end of the
ball screw that mates with the 40 on the motor. And that motor on about
37 volts can move the Z at 70+ IPM with quite a bit of drag from the
gibs. I was amazed, a nearly identical 425 oz/in motor direct drives a
similar screw in the G0704, and tops out at about 70 IPM in mid travel
with a 42 volt psu. Set for a G0 of about 48 because thats all it can
muster at the end of the tables travel, which obviously wedges the gibs
a bit when its 40 lbs out of balance.

Poking around in the detrius of the shop, I came across a bag I'd only
faintly remembered, with 2 brand new and one nearly so of the 1.5x70 OEM
chinese belts in it. I figured its about the right length, but I didn't
feel like coaxing the alu pulleys off and putting the OEM plastic stuff
back on, so I wrapped it around the new XL pulley and couldn't make it
slip a cog. Humm, so I rolled it on, then jacked up the tension. And
taking light cuts, running at about 150 revs, the belt was being slapped
around quite aq bit becaquse of the cog spacing miss-match but it wasn't
slipping. 4 hours later it must be wearing in as its not being slapped
around near as much, but I paused it as it was not quite done since I
was only cutting .1mm off the radius per pass, and it needed to cool as
the whole housing, heated by radiant heat from the upper pulley was
above 125F but the rest of the headstock was below 105F. And this was
at nominally 150 rpm, making cast iron dust like fine playsand.

Because normally thats all covered up, I wonder if even the correct XL
belt was heating that badly at 5x or 7x the motor speed. Could be part
of the failure mechanism of the kevlar/neoprene belt, and I'll sure
check it out when the bigger pulley's and the 140XL037 belts arrive.

Thanks Andy.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
andy pugh
2016-06-01 10:09:49 UTC
Permalink
Post by Gene Heskett
There's nothing preventing me from boring it tapered and making
another, smaller than I did for the z motors gear, miniature taperlock
hub, perhaps with a dozen holes alternating threaded and clearance,
As an alternative, you could consider using a single nut:
The 8th picture down here: http://bodgesoc.blogspot.de/2016/01/holbrook5.html
Is the taperlock I made to hold a small sprocket to a large shaft. The
sprocket is bored to a taper, and the nut pulls the taper through.
You need a lathe to make it, though, which might present you with a problem.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-06-01 15:19:27 UTC
Permalink
Post by andy pugh
Post by Gene Heskett
There's nothing preventing me from boring it tapered and making
another, smaller than I did for the z motors gear, miniature
taperlock hub, perhaps with a dozen holes alternating threaded and
clearance,
http://bodgesoc.blogspot.de/2016/01/holbrook5.html
Something along those lines. But more than likely a miniature "taperlock"
type hub if I can pull off enough precision, possibly by leaveing about
1/4 of the hole in the pulley at shaft diameter (the hub is just over an
inch thick) and tapering the rest of it at 7 degrees. So the taperlock
wedgeing piece, with a 3 or even 6 bolt drive pattern with a jack out
hole between every other hole of the 6 that are tapped, say for 3mm.5
screws. The spinning cap screw heads may need some clearance made in the
front face of the z motor mount. Or possibly make a counterbore
about .070" deep in the flange. Since the thru hole in that spindle
can't pass a stock rod much over 3/4", the outer edge of that flange
will probably be "missing" if I make a fresh countershaft thats a
full .500" in diameter. Its 10mm now, and if I only bore the pulley
coming to 10mm, that would leave more room for drawbolts, if its flange
OD is .750", still the 3mm.5's I expect. The pulley on it now had only
a coat of green locktite and its set screws, and didn't break loose even
as it was stripping teeth off the belt. I expect to have to demolish it
to remove it as my only puller is too big and ungainly to use in that
small a space even with the motor and jackshaft out on a table.

But I've sorted that problem before. Enough times that I am thoroughly
tired of it, that lower pulley in the OEM version is abs plastic, and
I've burned up at least a 12 pack of them puppy's along with the belt,
which strips its even lower profile teeth, and by the time I can hit the
big yellow button, the pulley is burned to an unrecognizable mess with
the cogs all smeared against each other.

Even with the OEM 400 watt motor, this thing was a design error that
should have been torn off the napkin and burned in the ashtray, never to
have seen fruition even in plastic.

Did I mention I'm tired of it?

Yes, I am tired of it.
Post by andy pugh
Is the taperlock I
made to hold a small sprocket to a large shaft. The sprocket is bored
to a taper, and the nut pulls the taper through. You need a lathe to
make it, though, which might present you with a problem.
That part I actually have working, aleit slowly. In shuffling thru the
detrius in the "shop" building here, I found a bag with 3 of the old 1.5
x 70 belts, so I installed one of those. Its working at a light load,
but heating the pulleys quite hot if I ask it for more than 150 rpm's, I
assume from the belt to gullet missmatch. The same length of XL belt
carries 65 cogs, this one has 70. And its pulling .2mm off the diameter
of a big block of cast iron per pass. And leaving a vibration pattern
even at that light a cut. So I will, when this piece is out of the
chuck, be working on the hal file again, to put a siggen in the spindle
speed path to put at least a 10% speed wobble with about a 2 second
cycle rate, using siggen's sine wave output so the PID isn't pushed too
hard to keep up. And trying in my head, to figure out how to make the
sine wave output gain be 10% of the requested speed from motion. And at
least an on/off button someplace in the axis gui as I don't think I'd
want it doing that for a g76 or a g33.1. :)

So I may be able to make something suitable. When the McMaster order
gets here. I got the receipt, in pdf format this morning. Had to call
them to place the order as I am not passing out my unlisted number to
any big firm that will sell the damned list. Not open for discussion
even. The politicals used up my last bit of patience in the last
election cycle when some auto dialer called us up at 3 am to urge us to
vote for someone whom I considered as the worst of two evils by a very
long row of apple trees. The was indeed the last straw.

Thanks Andy.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
andy pugh
2016-06-01 15:39:21 UTC
Permalink
Post by Gene Heskett
that lower pulley in the OEM version is abs plastic, and
I've burned up at least a 12 pack of them puppy's along with the belt,
which strips its even lower profile teeth, and by the time I can hit the
big yellow button, the pulley is burned to an unrecognizable mess with
the cogs all smeared against each other.
Have you considered the use of bicycle chain?
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-06-01 15:58:27 UTC
Permalink
Post by andy pugh
Post by Gene Heskett
that lower pulley in the OEM version is abs plastic, and
I've burned up at least a 12 pack of them puppy's along with the
belt, which strips its even lower profile teeth, and by the time I
can hit the big yellow button, the pulley is burned to an
unrecognizable mess with the cogs all smeared against each other.
Have you considered the use of bicycle chain?
Even #25 is too big Andy. I have a roll of it with 4 or 5 feet left. I
think the same would apply to your r1's timeing chain too, in this
cramped space.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Gregg Eshelman
2016-06-01 20:08:27 UTC
Permalink
Might be too small?
Power animated displays, robotics, model trains and other miniature mechanisms. Tough, durable, self-lubricating acetal resin chain links snap apart for easy adjustment. Chain pitch: .1227 inch; width .162 inch; thickness .082 inch. (Note: Chain sold only in increments of one foot.)
http://www.micromark.com/miniature-drive-chain-price-per-foot,9716.html

From: Gene Heskett <***@shentel.net>
To: emc-***@lists.sourceforge.net
Sent: Wednesday, June 1, 2016 9:58 AM
Subject: Re: [Emc-users] drive belt for 7x12 NOT OEM
Post by andy pugh
Post by Gene Heskett
that lower pulley in the OEM version is abs plastic, and
I've burned up at least a 12 pack of them puppy's along with the
belt, which strips its even lower profile teeth, and by the time I
can hit the big yellow button, the pulley is burned to an
unrecognizable mess with the cogs all smeared against each other.
Have you considered the use of bicycle chain?
Even #25 is too big Andy. I have a roll of it with 4 or 5 feet left. I
think the same would apply to your r1's timeing chain too, in this
cramped space.
andy pugh
2016-06-01 22:29:17 UTC
Permalink
Post by Gregg Eshelman
Might be too small?
Power animated displays, robotics, model trains and other miniature mechanisms. Tough, durable, self-lubricating acetal resin chain links snap apart for easy adjustment.
Well, at least they would be easy to snap together again when they
broke. But if an XL belt isn't coping, I doubt that plastic chain
would.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-06-01 23:20:13 UTC
Permalink
Post by Gregg Eshelman
Might be too small?
I think so Gregg. They don't have suitable sprockets with big enough hubs
to move the torque I need to move, and there is do data on the tensil
strength of the chain itself. So while its cute, its strictly for moving
a bit of cardboard IMO.

Thanks for the link, it may have been golden. But not for me.
Post by Gregg Eshelman
Power animated displays, robotics, model trains and other miniature
mechanisms. Tough, durable, self-lubricating acetal resin chain links
snap apart for easy adjustment. Chain pitch: .1227 inch; width .162
inch; thickness .082 inch. (Note: Chain sold only in increments of one
foot.)
http://www.micromark.com/miniature-drive-chain-price-per-foot,9716.htm
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Gregg Eshelman
2016-06-02 04:34:06 UTC
Permalink
There's bound to be some roller chain size between that and bicycle chain, which would be ideal for your application.




From: Gene Heskett <***@shentel.net>
To: emc-***@lists.sourceforge.net
Sent: Wednesday, June 1, 2016 5:20 PM
Subject: Re: [Emc-users] drive belt for 7x12 NOT OEM
Post by Gregg Eshelman
Might be too small?
I think so Gregg. They don't have suitable sprockets with big enough hubs
to move the torque I need to move, and there is do data on the tensil
strength of the chain itself. So while its cute, its strictly for moving
a bit of cardboard IMO.

Thanks for the link, it may have been golden. But not for me.
Post by Gregg Eshelman
Power animated displays, robotics, model trains and other miniature
mechanisms. Tough, durable, self-lubricating acetal resin chain links
snap apart for easy adjustment. Chain pitch: .1227 inch; width .162
inch; thickness .082 inch. (Note: Chain sold only in increments of one
foot.)
http://www.micromark.com/miniature-drive-chain-price-per-foot,9716.htm
John Kasunich
2016-06-02 13:15:35 UTC
Permalink
Post by Gregg Eshelman
There's bound to be some roller chain size between that and bicycle chain, which would be ideal for your application.
Unless this is a mighty slow lathe, I don't think chain is the
appropriate drive mechanism.

It sounds like part of the problem is a spindle pulley that
is too small. That hurts twice. First, it reduces the lever
arm and requires more belt pull per ft-lb of torque delivered.
Second, it reduces the belt wrap and number of teeth engaged,
which increases the load per tooth even more.

Bigger pulleys help in other ways too. A big spindle pulley
provides some flywheel effect which can reduce chatter
and relieves the motor/belt of the worst shock loads.

I've never seen this lathe, only tried to parse Gene's written
explanations. So I have no idea what the real limitations are
as far as pulley size, belt width, etc.

A photo or two of the spindle area would help. What are the
real constraints on pulley size and drivetrain configuration?

Also helpful would be the following:

Motor rated power (hp or watts, at a particular speed)
Motor rated speed (at which it develops rated HP)
Motor speed range when used with the drive in question
Desired spindle speed range
Post by Gregg Eshelman
From that information, you can use online resources to
determine the proper type and size of belt and the proper
pulleys to design a reliable drivetrain. Once you know what
you need, then you figure out how to make it fit.

This chart is a good starting point.
http://www.sdp-si.com/D265/HTML/D265T006.html
Given the rated HP and the speed of the faster pulley it
shows you which belt families can handle the power.

Doing it any other way is bass-ackwards IMHO.

It sounds like the existing belt is an XL series. According
to the chart, the maximum power for an XL belt is about
1/2HP at 3450 RPM, about 1/3HP at 1750 RPM. And that
assumes properly chosen belt widths (not 3/8") and pulley
sizes. If you've increased the motor beyond those limits
(or even close to them), there is simply no way it is going
to be reliable.

Another option instead of timing belts is multi-groove
V-belts (J series). They have the advantage that you can
make your own pulleys (if you have a working lathe).
A spindle drive shouldn't need positive registration, so
you don't really need toothed belts.
--
John Kasunich
***@fastmail.fm
andy pugh
2016-06-02 13:45:11 UTC
Permalink
Post by John Kasunich
Unless this is a mighty slow lathe, I don't think chain is the
appropriate drive mechanism.
Silent chain has been used on a number of lathes historically:
http://www.lathes.co.uk/southbend/page12.html

And the cam-chain in my motorcycle runs up to 14,000 rpm.

A conventional roller chain might well not be as smooth as one might
like in a lathe application, though.

I haven't posted this here yet:

This is my current project, which is using motorcycle cam-chains to
drive the ball screws as an experiment.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
John Kasunich
2016-06-02 14:40:52 UTC
Permalink
Post by andy pugh
Post by John Kasunich
Unless this is a mighty slow lathe, I don't think chain is the
appropriate drive mechanism.
http://www.lathes.co.uk/southbend/page12.html
That South Bend installation had a recommended motor speed
of 900 RPM. Gene's lathe uses a motor that I think runs 4000 RPM.

My Van Norman mill used a silent chain from the 1/4 HP 1800 RPM
feed motor to the input shaft of the feed gearbox. Pulley and chain
were both worn and the chain would climb out of the teeth and
skip. There was enough meat on the large pulley that I could turn
off the silent-chain teeth and re-cut XL timing belt teeth. I put an
off-the-shelf XL pulley on the motor and back in service.
Post by andy pugh
And the cam-chain in my motorcycle runs up to 14,000 rpm.
Fully enclosed and oil lubricated. And properly engineered for
the task.
Post by andy pugh
A conventional roller chain might well not be as smooth as one might
like in a lathe application, though.
http://youtu.be/woU927Tqoo8
This is my current project, which is using motorcycle cam-chains to
drive the ball screws as an experiment.
How fast do the ballscrews turn?

I don't doubt that a chain could be made to work, but on a lathe
as small as Gene's I think it is far from the ideal solution.
--
John Kasunich
***@fastmail.fm
andy pugh
2016-06-02 14:54:04 UTC
Permalink
Post by John Kasunich
That South Bend installation had a recommended motor speed
of 900 RPM. Gene's lathe uses a motor that I think runs 4000 RPM.
Granted.
Post by John Kasunich
Post by andy pugh
And the cam-chain in my motorcycle runs up to 14,000 rpm.
Fully enclosed and oil lubricated. And properly engineered for
the task.
Indeed. But also good for around 450 million revolutions, and counting.
(based on the current milage of 105,000 miles and assuming it was done
at 70mph and 5000rpm)

Somewhere between the two might be a place for a lathe drive.

Clearly belts are not working, so what else is there?
Post by John Kasunich
How fast do the ballscrews turn?
Nothing like as fast, about 1000 rpm.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
John Kasunich
2016-06-02 16:48:26 UTC
Permalink
Post by andy pugh
Clearly belts are not working, so what else is there?
Clearly the EXISTING belts are not working.

They were designed for the original motor and original motor controller,
and may well have been marginal for that application.

I'm 99% sure Gene has changed both motor and controller. I know he's
using Jon Elson's motor controller, with a much higher current rating.
I'm pretty sure he's also using a much stronger motor. I wouldn't be
surprised if he's doubled or even tripled the available peak torque.
Now he has to uprate the drivetrain to match.

I've seen toothed belts used to transmit 100HP (big belts on big pulleys).
Certainly belts can do the job if sized properly. Industrial sized lathes
(including yours I think) usually use a combination of belts and gears.
Chains are very rare in lathe drivetrains.
--
John Kasunich
***@fastmail.fm
andy pugh
2016-06-02 17:00:49 UTC
Permalink
Post by John Kasunich
Clearly the EXISTING belts are not working.
Indeed, and the problem that is trying to be fixed is to transmit 3 x
the torque using a drive system inside the same envelope as the
existing (inadequate) belt.

I agree that chain drive would be inferior to a properly-designed belt
drive. But it seems that a properly-designed belt drive is not an
option.

My solution to a very similar problem on my cheap Chinese lathe was to
throw away the belt cover and fit dual V-belts.
https://picasaweb.google.com/108164504656404380542/CNCUnsorted#5437112986322828066

I am merely trying to suggest solutions that meet the rather bizarre
boundary conditions applied to the problem. The real solution is. of
course, to buy the Sheldon he keeps talking about and re-cycle the
Chinese lathe as ballast.
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-06-03 04:15:37 UTC
Permalink
Post by John Kasunich
Post by andy pugh
Post by John Kasunich
Unless this is a mighty slow lathe, I don't think chain is the
appropriate drive mechanism.
http://www.lathes.co.uk/southbend/page12.html
That South Bend installation had a recommended motor speed
of 900 RPM. Gene's lathe uses a motor that I think runs 4000 RPM.
My Van Norman mill used a silent chain from the 1/4 HP 1800 RPM
feed motor to the input shaft of the feed gearbox. Pulley and chain
were both worn and the chain would climb out of the teeth and
skip. There was enough meat on the large pulley that I could turn
off the silent-chain teeth and re-cut XL timing belt teeth. I put an
off-the-shelf XL pulley on the motor and back in service.
Post by andy pugh
And the cam-chain in my motorcycle runs up to 14,000 rpm.
Fully enclosed and oil lubricated. And properly engineered for
the task.
Post by andy pugh
A conventional roller chain might well not be as smooth as one might
like in a lathe application, though.
http://youtu.be/woU927Tqoo8
This is my current project, which is using motorcycle cam-chains to
drive the ball screws as an experiment.
How fast do the ballscrews turn?
I don't doubt that a chain could be made to work, but on a lathe
as small as Gene's I think it is far from the ideal solution.
Progress report:

First, I cannot write gcode that really does what I want. I wanted to
bore a 10.004 hole to fit my homemade 10mm shaft as the new pulleys come
with only a 1/4 bore. So I planted a 1/4" tool in the hole, clamped it
down and touched the machine off at x0y0. I had to keep asking it for a
bigger hole which I did about 5 times before I managed to get a 10.010
hole, which fit the shaft until it ran into the burrs from the
previously tightened set screws. So its in and turning the chuck but
the bigger pulley is forceing to design a different method of setting a
wedge in the jackshaft frame that I can use to tighten the belt until it
sounds like froggy's magic twanger. That is to prevent the frame from
lifting under a heavy cut, giving the belt slack enough to jump teeth.

The increased diameter also means the angle bracket I put on the lathes
casting to help hold the housing for the spindle electronics is going to
need shortening about 5/8" and a new hole drilled for the screw. Piddly
stuff but it still takes time.

And I just found the jackshaft bearing thats doing all the grumbling
recently, so once the wedge problem is solved, I"ll pull it back out and
replace that bearing as I bought 4 of them. Its taken quite a beating
two or 11 times changing this darned pulley. I've lost track of how many
of the OEM plastic pulleys I've burned up.

At that point, since machineing that wedge will be a bit of a project, I
decided my back was done for the day, and since its almost midnight, its
beer thirty too. And maybe even a bowl of ice cream.

I got two stout neighbors and one supervisor, to help me pull the
fiberglass tonneau cover off my GMC, so once I get it unloaed, I can
load up a bandsaw I sold to an old friend in TN, and deliver it, spend
the night since I've not seen him in person for about 15 years, then
come back about 100 miles, rent a trailer from a local u-haul big enough
to carry the bigger lathe I'm buying, and pull it home. And I'm not at
all started on clearing out enough detrious to make a place for the
lathe.

Don't get old folks, it eats into your productive work time when it hurts
to pick up 30 lbs these days. Its a right bummer. Takes too much time
to rig a skyhook with a trolley and use a multisheave come-a-long to
move something I could have picked up and walked off with 5 years ago.

:( But I keep plugging along. Take care everyone.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Gene Heskett
2016-06-02 19:16:42 UTC
Permalink
Post by John Kasunich
Post by Gregg Eshelman
There's bound to be some roller chain size between that and bicycle
chain, which would be ideal for your application.
Unless this is a mighty slow lathe, I don't think chain is the
appropriate drive mechanism.
It sounds like part of the problem is a spindle pulley that
is too small. That hurts twice. First, it reduces the lever
arm and requires more belt pull per ft-lb of torque delivered.
Second, it reduces the belt wrap and number of teeth engaged,
which increases the load per tooth even more.
Bigger pulleys help in other ways too. A big spindle pulley
provides some flywheel effect which can reduce chatter
and relieves the motor/belt of the worst shock loads.
A larger upper pulley that drives the lathes head countershaft is not
possible as it runs into the rear of the spindle at about 1 more cog.
Post by John Kasunich
I've never seen this lathe, only tried to parse Gene's written
explanations. So I have no idea what the real limitations are
as far as pulley size, belt width, etc.
Basically its such a poor design that I an biting the bullet and buying a
bigger one, which I am trying to make a hole for in the detrious on my
garage floor right now, and which I need to get tuit.
Post by John Kasunich
A photo or two of the spindle area would help. What are the
real constraints on pulley size and drivetrain configuration?
Motor rated power (hp or watts, at a particular speed)
Motor rated speed (at which it develops rated HP)
Motor speed range when used with the drive in question
Desired spindle speed range
From that information, you can use online resources to
determine the proper type and size of belt and the proper
pulleys to design a reliable drivetrain. Once you know what
you need, then you figure out how to make it fit.
This chart is a good starting point.
http://www.sdp-si.com/D265/HTML/D265T006.html
Given the rated HP and the speed of the faster pulley it
shows you which belt families can handle the power.
Doing it any other way is bass-ackwards IMHO.
It sounds like the existing belt is an XL series. According
to the chart, the maximum power for an XL belt is about
1/2HP at 3450 RPM, about 1/3HP at 1750 RPM. And that
assumes properly chosen belt widths (not 3/8") and pulley
sizes. If you've increased the motor beyond those limits
(or even close to them), there is simply no way it is going
to be reliable.
Another option instead of timing belts is multi-groove
V-belts (J series). They have the advantage that you can
make your own pulleys (if you have a working lathe).
A spindle drive shouldn't need positive registration, so
you don't really need toothed belts.
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
John Kasunich
2016-06-02 21:18:24 UTC
Permalink
Post by Gene Heskett
Post by John Kasunich
It sounds like part of the problem is a spindle pulley that
is too small. That hurts twice. First, it reduces the lever
arm and requires more belt pull per ft-lb of torque delivered.
Second, it reduces the belt wrap and number of teeth engaged,
which increases the load per tooth even more.
Bigger pulleys help in other ways too. A big spindle pulley
provides some flywheel effect which can reduce chatter
and relieves the motor/belt of the worst shock loads.
A larger upper pulley that drives the lathes head countershaft is not
possible as it runs into the rear of the spindle at about 1 more cog.
When I wrote that I was unaware that this lathe had gears inside
the headstock and that the belt was driving the shaft with the
gears rather than driving the spindle directly.

I think your "bigger better lathe" approach is the right one. But
if for some reason I was stuck with the 7x lathe, I would ignore
the countershaft with its plastic gears and put a nice big pulley
on the back of the main spindle....
--
John Kasunich
***@fastmail.fm
Gene Heskett
2016-06-03 04:34:22 UTC
Permalink
Post by John Kasunich
Post by Gene Heskett
Post by John Kasunich
It sounds like part of the problem is a spindle pulley that
is too small. That hurts twice. First, it reduces the lever
arm and requires more belt pull per ft-lb of torque delivered.
Second, it reduces the belt wrap and number of teeth engaged,
which increases the load per tooth even more.
Bigger pulleys help in other ways too. A big spindle pulley
provides some flywheel effect which can reduce chatter
and relieves the motor/belt of the worst shock loads.
A larger upper pulley that drives the lathes head countershaft is
not possible as it runs into the rear of the spindle at about 1 more
cog.
When I wrote that I was unaware that this lathe had gears inside
the headstock and that the belt was driving the shaft with the
gears rather than driving the spindle directly.
I think your "bigger better lathe" approach is the right one. But
if for some reason I was stuck with the 7x lathe, I would ignore
the countershaft with its plastic gears and put a nice big pulley
on the back of the main spindle....
I have considered that, John, unforch no one makes a "J" format
polygroove pulley big enough to be usefull as 4" seems to be about tops.

I already am using the OEM 5 groove that comes on the motor as part of
its huge fan/flywheel, which is about a 1" pitch diameter, and running
over a 3" pulley that matches and that turns the jackshaft tht carries
the pulley that burns up the belt, and if its the plastic OEM pulley,
its burned up too. I'de love to use it as the horsepower ratings of that
belt setup kick the best of the cogged belts about 3 drainages over. I
even started to make a pulley, but can't buy the tooling to do it right
anyplace. To do it right, I'd need a 1" thick piece of 7078-T6 about 7"
in its narrowest dimension, and some vcmt tooling. And I'd machine a
360 slot plus index encoder slot setup inside the outer rim too. So if
this doesn't help enough to suit me, I'll be online looking for some alu
to make that pulley with. But I'll have to make it on the bigger lathe
as this one swings about 4" smaller than that needs.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
andy pugh
2016-05-31 08:30:11 UTC
Permalink
Post by Gene Heskett
For want of a better project to keep me out of the bars tonight, I went
out and extracted the stripped belt off the toy lathe just now, find it
well labeled as a 130XL037, 3/8" wide, 65 tooth belt. It appears that I
had already replaced the ultra teeny drive pulley that stripped the last
belt easily had already been replaced with a 15 tooth model.
I see that the T5 style (steel reinforced) belts are available up to 32mm wide.
Perhaps try those instead?
--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916
Gene Heskett
2016-05-31 12:12:01 UTC
Permalink
Post by andy pugh
Post by Gene Heskett
For want of a better project to keep me out of the bars tonight, I
went out and extracted the stripped belt off the toy lathe just now,
find it well labeled as a 130XL037, 3/8" wide, 65 tooth belt. It
appears that I had already replaced the ultra teeny drive pulley
that stripped the last belt easily had already been replaced with a
15 tooth model.
I see that the T5 style (steel reinforced) belts are available up to
32mm wide. Perhaps try those instead?
Width and diameter of the upper pulley are determined by clearance to the
spindle shaft itself. So I'm stuck with the XL, 3/8" wide.

But I believe I have it grokked using that belt calculator link that was
posted here last night. A 140XL037 belt and a 26 tooth double flanged
pulley on the bottom should be very close to the same center to center,
and will engage 5 more cogs on the lower pulley, from 7 to 12. I like
as that will slow the motor by reducing the step down from nominally 2.1
to about 1.2/1. That will put more pressure on the backgears which will
be in low more of the time. But those nylon gears are all metal now, and
should stand up to that.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
John Thornton
2016-05-31 10:31:07 UTC
Permalink
I assume a 1/2" belt won't fit the spindle so have you tried the kevlar
belts? McMaster 51514T315 <http://www.mcmaster.com/#51514T315>

JT
Post by Gene Heskett
Hi all;
For want of a better project to keep me out of the bars tonight, I went
out and extracted the stripped belt off the toy lathe just now, find it
well labeled as a 130XL037, 3/8" wide, 65 tooth belt. It appears that I
had already replaced the ultra teeny drive pulley that stripped the last
belt easily had already been replaced with a 15 tooth model. So even
with about 7 cogs fully engaged, this motor still had the cojones to
strip the teeth off the belt. So I am thinking out ordering a 140 or
even a 150 (75 cogs) belt and a bigger lower drive pulley which should
get more cogs engaged. That will of course raise the spindle speed and
probably make me run on low backgear more often, but this motor has the
cojones to do that so I am not worried too much.
So my question is, if I buy a 150 cog belt, and the existing lower pulley
has 16 cogs now, and I add 10 more to the belt, making it 75 it sounds
as if I would need to add another 5 to the almost half circle that would
be engaging the belt on each side, so the 16 cog pulley now would turn
into a 26 if I want the center to center distance to remain within say
2mm's of what it is now. That seems to me like if I tension it to about
high C, that ought to be able to survive that 1 hp motor long enough to
at least finish one job, bearing in mind there is a 3/1 stepdown between
the motor, and the shaft turning this lower pulley.
Is my math somewhere near correct? And would I be better off paying the
price of one of the white poly/kevlar belts as opposed to this black one
with a few strabds of kevlar in the backing and teeth that look like a
glass reenforced black rubber? I'll check McMaster-Carr, but I can get
this belt for about $4/copy from the prople that used to be GoodYear.
Comments anybody? Or did my mental math blow it, like its been known to
do several times before?
Cheers, Gene Heskett
Gene Heskett
2016-05-31 12:54:40 UTC
Permalink
Post by John Thornton
I assume a 1/2" belt won't fit the spindle so have you tried the
kevlar belts? McMaster 51514T315 <http://www.mcmaster.com/#51514T315>
JT
That one is $23.62/copy in 3/8 by 70 cogs. The one next to it called
dust-free at $4.76 (1679K126) looks interesting. And for some reason
its cheaper than the regular fiberglass & neoprene XL ??

5 belts, 2 pulley's ordered. The pulleys will need bored out for the
bigger 1/2" shaft. Other than the time to setup and locate the center of
the cogs, shrug.
Post by John Thornton
Post by Gene Heskett
Hi all;
For want of a better project to keep me out of the bars tonight, I
went out and extracted the stripped belt off the toy lathe just now,
find it well labeled as a 130XL037, 3/8" wide, 65 tooth belt. It
appears that I had already replaced the ultra teeny drive pulley
that stripped the last belt easily had already been replaced with a
15 tooth model. So even with about 7 cogs fully engaged, this motor
still had the cojones to strip the teeth off the belt. So I am
thinking out ordering a 140 or even a 150 (75 cogs) belt and a
bigger lower drive pulley which should get more cogs engaged. That
will of course raise the spindle speed and probably make me run on
low backgear more often, but this motor has the cojones to do that
so I am not worried too much.
So my question is, if I buy a 150 cog belt, and the existing lower
pulley has 16 cogs now, and I add 10 more to the belt, making it 75
it sounds as if I would need to add another 5 to the almost half
circle that would be engaging the belt on each side, so the 16 cog
pulley now would turn into a 26 if I want the center to center
distance to remain within say 2mm's of what it is now. That seems
to me like if I tension it to about high C, that ought to be able to
survive that 1 hp motor long enough to at least finish one job,
bearing in mind there is a 3/1 stepdown between the motor, and the
shaft turning this lower pulley.
Is my math somewhere near correct? And would I be better off paying
the price of one of the white poly/kevlar belts as opposed to this
black one with a few strabds of kevlar in the backing and teeth that
look like a glass reenforced black rubber? I'll check
McMaster-Carr, but I can get this belt for about $4/copy from the
prople that used to be GoodYear.
Comments anybody? Or did my mental math blow it, like its been
known to do several times before?
Cheers, Gene Heskett
----------------------------------------------------------------------
-------- What NetFlow Analyzer can do for you? Monitors network
bandwidth and traffic patterns at an interface-level. Reveals which
users, apps, and protocols are consuming the most bandwidth. Provides
multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make
informed decisions using capacity planning reports.
https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Todd Zuercher
2016-06-01 16:12:11 UTC
Permalink
Sorry Gene, but I have to say this. As much as we've heard you complain about how worthless your lathe is, perhaps it is (or well past) time to cut your losses with that thing and move on with something a little more up to the task.

----- Original Message -----
From: "Gene Heskett" <***@shentel.net>
To: emc-***@lists.sourceforge.net
Sent: Wednesday, June 1, 2016 11:58:27 AM
Subject: Re: [Emc-users] drive belt for 7x12 NOT OEM
Post by andy pugh
Post by Gene Heskett
that lower pulley in the OEM version is abs plastic, and
I've burned up at least a 12 pack of them puppy's along with the
belt, which strips its even lower profile teeth, and by the time I
can hit the big yellow button, the pulley is burned to an
unrecognizable mess with the cogs all smeared against each other.
Have you considered the use of bicycle chain?
Even #25 is too big Andy. I have a roll of it with 4 or 5 feet left. I
think the same would apply to your r1's timeing chain too, in this
cramped space.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
_______________________________________________
Emc-users mailing list
Emc-***@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
Gene Heskett
2016-06-01 18:42:40 UTC
Permalink
Post by Todd Zuercher
Sorry Gene, but I have to say this.
Don't be sorry Todd, I am well aware of the need, and in between
honeytdo's and my back playing out and screaming for another pill, I am
working on making room in the garage for the cure, with a Sheldon
nameplate on it. But I also have to round up a 1 ton rated or better
crane to set it in place with when I get back with it on a u-haul
trailer sometime next week. But at the instant, no place to put it
exists. So first stop is Lowes for a set of shelves about 7' high with
at least 7 or 8 shelves so I can sort, this hand in the trash trailer
and that hand on a shelf for later use by a confirmed packrat. But first
I have to clear in front of a single shelf and worktop 2' x 4' $20 thing
and convert it to trailer filler once I've moved about a thou in clamps
of various ancestry off its single shelf. With my back, thats all of 2
days work for me. Too bad I can't replace it for the same price as this
lathe. :(
Post by Todd Zuercher
As much as we've heard you
complain about how worthless your lathe is, perhaps it is (or well
past) time to cut your losses with that thing and move on with
something a little more up to the task.
----- Original Message -----
Sent: Wednesday, June 1, 2016 11:58:27 AM
Subject: Re: [Emc-users] drive belt for 7x12 NOT OEM
Post by andy pugh
Post by Gene Heskett
that lower pulley in the OEM version is abs plastic, and
I've burned up at least a 12 pack of them puppy's along with the
belt, which strips its even lower profile teeth, and by the time I
can hit the big yellow button, the pulley is burned to an
unrecognizable mess with the cogs all smeared against each other.
Have you considered the use of bicycle chain?
Even #25 is too big Andy. I have a roll of it with 4 or 5 feet left. I
think the same would apply to your r1's timeing chain too, in this
cramped space.
Cheers, Gene Heskett
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
BRIAN GLACKIN
2016-06-01 18:50:28 UTC
Permalink
Gene,

I have a 3 ton engine lift you can have to maneuver things about, but I
doubt you want to trek clear across PA to the Philly area to get it.
Post by Gene Heskett
Post by Todd Zuercher
Sorry Gene, but I have to say this.
Don't be sorry Todd, I am well aware of the need, and in between
honeytdo's and my back playing out and screaming for another pill, I am
working on making room in the garage for the cure, with a Sheldon
nameplate on it. But I also have to round up a 1 ton rated or better
crane to set it in place with when I get back with it on a u-haul
trailer sometime next week. But at the instant, no place to put it
exists. So first stop is Lowes for a set of shelves about 7' high with
at least 7 or 8 shelves so I can sort, this hand in the trash trailer
and that hand on a shelf for later use by a confirmed packrat. But first
I have to clear in front of a single shelf and worktop 2' x 4' $20 thing
and convert it to trailer filler once I've moved about a thou in clamps
of various ancestry off its single shelf. With my back, thats all of 2
days work for me. Too bad I can't replace it for the same price as this
lathe. :(
Post by Todd Zuercher
As much as we've heard you
complain about how worthless your lathe is, perhaps it is (or well
past) time to cut your losses with that thing and move on with
something a little more up to the task.
----- Original Message -----
Sent: Wednesday, June 1, 2016 11:58:27 AM
Subject: Re: [Emc-users] drive belt for 7x12 NOT OEM
Post by andy pugh
Post by Gene Heskett
that lower pulley in the OEM version is abs plastic, and
I've burned up at least a 12 pack of them puppy's along with the
belt, which strips its even lower profile teeth, and by the time I
can hit the big yellow button, the pulley is burned to an
unrecognizable mess with the cogs all smeared against each other.
Have you considered the use of bicycle chain?
Even #25 is too big Andy. I have a roll of it with 4 or 5 feet left. I
think the same would apply to your r1's timeing chain too, in this
cramped space.
Cheers, Gene Heskett
Cheers, Gene Heskett
--
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
Gene Heskett
2016-06-01 23:06:26 UTC
Permalink
Post by BRIAN GLACKIN
Gene,
I have a 3 ton engine lift you can have to maneuver things about, but
I doubt you want to trek clear across PA to the Philly area to get it.
Thanks for the offer Brian, but I believe I can source one about 2 houses
down the hill, when I asked him to do a long block swap in my GMC around
2 years back he had no trouble producing one big enough to handle that
305, ready to run, like it was a tooth pick. I just haven't asked him
yet, and it might cost me a small daily rental. Thats no biggie. And
he's a good neighbor to have around. He watches real good. In fact, all
of my neighbors are sweethearts. I have lived in neighorhoods where 30
minutes after the last light goes out somebody is shaking the doorknobs
quietly. Thats spooky, and could get somebody offed if they came in by
way of a prybar under an unlocked window.

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
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