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#MISC Pulleys?
#MISC
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Looking?for pulley and belt suggestions.
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I have 3.10Nm stepper with a 8mm shaft.
My leadscrew is 3/4 - 8tpi.
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The stepper has been criticised as to small for that leadscrew and suggestion to use pulleys.
So where do I find a pulley with a 3/4 bore and a matching (smaller) 8mm bore?
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Most 3/4 bore pulleys use a 4L V belt.
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I wonder if I could use some round urethane belting? A 5-6 mm round belt might run in a 4L grove.
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Ralph?
-- Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer |
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Richard
The lead-screw on my lathe is about 20mm diameter and 3mm pitch so very
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close to yours. I run a 3Nm stepper on my system with a 2:1 drive. A 40 tooth HTD pulley on the screw and a 20 tooth on the motor using a 5mm pitch 15mm wide? HTD belt. Belt and pulleys should be easily available from a good stockist, though in fact I made my 20 tooth pulley. Do not even consider using round belting to drive a lead-screw if the ultimate aim is some sort of ELS. Richard On 19/04/2020 15:37, Ralph Hulslander wrote:
Looking?for pulley and belt suggestions. |
开云体育Check Amazon and eBay for HTD pulleys with 3mm pitch. ?
Remember that you have a lathe, so you can bore out a 12mm or 15mm pulley to 3/4” pretty easily. ?For my Emco lathe (8mm stepper, 19 or 20mm leadscrew) I found a stock set that worked without any modifications. ?
19mm is extremely close to 3/4” too, so keep an eye out for that size.
The stepper drive needs a toothed timing belt so that it won’t slip. ?The very low torque encoder can be done with a flat, V or round belt.
alex
From: [email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...>
Sent: Sunday, April 19, 2020 7:50:55 AM To: [email protected] <[email protected]> Subject: Re: [digitalhobbyist] #MISC Pulleys? ?
The lead-screw on my lathe is about 20mm diameter and 3mm pitch so very
close to yours. I run a 3Nm stepper on my system with a 2:1 drive. A 40 tooth HTD pulley on the screw and a 20 tooth on the motor using a 5mm pitch 15mm wide? HTD belt. Belt and pulleys should be easily available from a good stockist, though in fact I made my 20 tooth pulley. Do not even consider using round belting to drive a lead-screw if the ultimate aim is some sort of ELS. Richard On 19/04/2020 15:37, Ralph Hulslander wrote: > Looking?for pulley and belt suggestions. > I have 3.10Nm stepper with a 8mm shaft. > My leadscrew is 3/4 - 8tpi. > The stepper has been criticised as to small for that leadscrew and > suggestion to use pulleys. > So where do I find a pulley with a 3/4 bore and a matching (smaller) > 8mm bore? > Most 3/4 bore pulleys use a 4L V belt. > I wonder if I could use some round urethane belting? A 5-6 mm round > belt might run in a 4L grove. > Ralph > -- > Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill > press, 40 watt laser, Consew brushless DC motors and a non working 3D > printer > |
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I turned an adaptor for the end of the lead screw. Onto that I put the 40T pulley. The motor has a 20T pulley.
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John -----Original Message----- |
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Richard
There is no way I would ever use a flat or round belt to drive an
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encoder if I wanted an accurate pulse train that matched the rotation being sensed. Torque has nothing to do with it, we are solely interested in the accuracy of the drive ratio be it 1:1 10:1 3:1 or whatever. A flat or Vee belt cannot provide that accuracy. Richard On 19/04/2020 17:00, alexphredorg wrote:
Check Amazon and eBay for HTD pulleys with 3mm pitch. |
开云体育How does a toothed belt provide higher accuracy than a round belt between the encoder and spindle? ?Assume high quality bearings and essentially zero friction at the encoder side.
A timing belt is ideal, but in my case it wasn’t a good option and the round belt has been working well including with thread cutting. ?A timing belt for me either would have added the lash and noise of a gear train or would require
making a custom two part pulley that clamped around the narrow part of my spindle — that would potentially also add inaccuracies.
alex
From: [email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...>
Sent: Sunday, April 19, 2020 10:03:03 AM To: [email protected] <[email protected]> Subject: Re: [digitalhobbyist] #MISC Pulleys? ?
There is no way I would ever use a flat or round belt to drive an
encoder if I wanted an accurate pulse train that matched the rotation being sensed. Torque has nothing to do with it, we are solely interested in the accuracy of the drive ratio be it 1:1 10:1 3:1 or whatever. A flat or Vee belt cannot provide that accuracy. Richard On 19/04/2020 17:00, alexphredorg wrote: > Check Amazon and eBay for HTD pulleys with 3mm pitch. > > Remember that you have a lathe, so you can bore out a 12mm or 15mm > pulley to 3/4” pretty easily. ?For my Emco lathe (8mm stepper, 19 or > 20mm leadscrew) I found a stock set that worked without any > modifications. > > 19mm is extremely close to 3/4” too, so keep an eye out for that size. > > The stepper drive needs a toothed timing belt so that it won’t slip. > ?The very low torque encoder can be done with a flat, V or round belt. > > > > > alex > ------------------------------------------------------------------------ > *From:* [email protected] <[email protected]> on > behalf of Richard via groups.io <edelec@...> > *Sent:* Sunday, April 19, 2020 7:50:55 AM > *To:* [email protected] <[email protected]> > *Subject:* Re: [digitalhobbyist] #MISC Pulleys? > The lead-screw on my lathe is about 20mm diameter and 3mm pitch so very > close to yours. > I run a 3Nm stepper on my system with a 2:1 drive. A 40 tooth HTD pulley > on the screw and a 20 tooth on the motor using a 5mm pitch 15mm wide > HTD belt. > Belt and pulleys should be easily available from a good stockist, though > in fact I made my 20 tooth pulley. > Do not even consider using round belting to drive a lead-screw if the > ultimate aim is some sort of ELS. > Richard > > On 19/04/2020 15:37, Ralph Hulslander wrote: > > Looking?for pulley and belt suggestions. > > I have 3.10Nm stepper with a 8mm shaft. > > My leadscrew is 3/4 - 8tpi. > > The stepper has been criticised as to small for that leadscrew and > > suggestion to use pulleys. > > So where do I find a pulley with a 3/4 bore and a matching (smaller) > > 8mm bore? > > Most 3/4 bore pulleys use a 4L V belt. > > I wonder if I could use some round urethane belting? A 5-6 mm round > > belt might run in a 4L grove. > > Ralph > > -- > > Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill > > press, 40 watt laser, Consew brushless DC motors and a non working 3D > > printer > > > > > > > |
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Richard
You say a timing belt is ideal, so you recognise the advantages. I am
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surprised that you cannot fit a timing pulley on your spindle, can you not just replace the original gear driving the change wheels? Richard On 19/04/2020 19:14, alexphredorg wrote:
How does a toothed belt provide higher accuracy than a round belt |
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The gear teeth are cut directly into the spindle.? The spindle is also larger at the left end, where the drive pulley mounts.? There is a photo here:
and this shows the whole arrangement:
The orange belt is sitting at the edge where the spindle diameter increases from 40mm to 44mm.
There is a difference between ideal and "there is no way".? I'm still trying to understand why you think a timing belt is required.
alex
From: [email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...>
Sent: Monday, April 20, 2020 1:42 AM To: [email protected] <[email protected]> Subject: Re: [digitalhobbyist] #MISC Pulleys? ?
You say a timing belt is ideal, so you recognise the advantages. I am
surprised that you cannot fit a timing pulley on your spindle, can you not just replace the original gear driving the change wheels? Richard On 19/04/2020 19:14, alexphredorg wrote: > How does a toothed belt provide higher accuracy than a round belt > between the encoder and spindle? ?Assume high quality bearings and > essentially zero friction at the encoder side. > > A timing belt is ideal, but in my case it wasn’t a good option and the > round belt has been working well including with thread cutting. ?A > timing belt for me either would have added the lash and noise of a > gear train or would require making a custom two part pulley that > clamped around the narrow part of my spindle — that would potentially > also add inaccuracies. > > > > alex > ------------------------------------------------------------------------ > *From:* [email protected] <[email protected]> on > behalf of Richard via groups.io <edelec@...> > *Sent:* Sunday, April 19, 2020 10:03:03 AM > *To:* [email protected] <[email protected]> > *Subject:* Re: [digitalhobbyist] #MISC Pulleys? > There is no way I would ever use a flat or round belt to drive an > encoder if I wanted an accurate pulse train that matched the rotation > being sensed. > Torque has nothing to do with it, we are solely interested in the > accuracy of the drive ratio be it 1:1 10:1 3:1 or whatever. A flat or > Vee belt cannot provide that accuracy. > Richard > > On 19/04/2020 17:00, alexphredorg wrote: > > Check Amazon and eBay for HTD pulleys with 3mm pitch. > > > > Remember that you have a lathe, so you can bore out a 12mm or 15mm > > pulley to 3/4” pretty easily. ?For my Emco lathe (8mm stepper, 19 or > > 20mm leadscrew) I found a stock set that worked without any > > modifications. > > > > 19mm is extremely close to 3/4” too, so keep an eye out for that size. > > > > The stepper drive needs a toothed timing belt so that it won’t slip. > > ?The very low torque encoder can be done with a flat, V or round belt. > > > > > > > > > > alex > > ------------------------------------------------------------------------ > > *From:* [email protected] <[email protected]> on > > behalf of Richard via groups.io <edelec@...> > > *Sent:* Sunday, April 19, 2020 7:50:55 AM > > *To:* [email protected] <[email protected]> > > *Subject:* Re: [digitalhobbyist] #MISC Pulleys? > > The lead-screw on my lathe is about 20mm diameter and 3mm pitch so very > > close to yours. > > I run a 3Nm stepper on my system with a 2:1 drive. A 40 tooth HTD pulley > > on the screw and a 20 tooth on the motor using a 5mm pitch 15mm wide > > HTD belt. > > Belt and pulleys should be easily available from a good stockist, though > > in fact I made my 20 tooth pulley. > > Do not even consider using round belting to drive a lead-screw if the > > ultimate aim is some sort of ELS. > > Richard > > > > On 19/04/2020 15:37, Ralph Hulslander wrote: > > > Looking?for pulley and belt suggestions. > > > I have 3.10Nm stepper with a 8mm shaft. > > > My leadscrew is 3/4 - 8tpi. > > > The stepper has been criticised as to small for that leadscrew and > > > suggestion to use pulleys. > > > So where do I find a pulley with a 3/4 bore and a matching (smaller) > > > 8mm bore? > > > Most 3/4 bore pulleys use a 4L V belt. > > > I wonder if I could use some round urethane belting? A 5-6 mm round > > > belt might run in a 4L grove. > > > Ralph > > > -- > > > Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill > > > press, 40 watt laser, Consew brushless DC motors and a non working 3D > > > printer > > > > > > > > > > > > > > > > > > |
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Richard
Ok I see that you have some problems which you have dealt with in your
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own way. As far as I am concerned the only way I can guarantee a correct relationship between spindle position and encoder position is with a timing belt. Our attitudes obviously differ lets leave it at that. Keep safe Richard On 20/04/2020 15:47, alexphredorg wrote:
The gear teeth are cut directly into the spindle.? The spindle is also |
开云体育Perhaps do an experiment for all of us. Here's the premise. ? As long as the two pulley V grooves are identical in shape and depth and the same diameter of course and the belt is the same diameter over its entire length the encoder and the spindle should stay in sync. ? So with the lathe stopped place a ruler along both pulleys aligned with the center of each pulley axis and draw a line on each pulley from the center in the direction of the other pulley. ? Now if you were using toothed belts months/years later when you turn the spindle by hand until the lines point to each other a ruler will show they still line up. ? The question is, over a few minutes, hours, days will the lines on the non-toothed belt pulleys still line up?? ? If they do you won't have slippage. If they don't and it's in the minutes or hours then you can't trust their position accuracy. ? John Dammeyer ? ? From: [email protected] [mailto:[email protected]] On Behalf Of alexphredorg
Sent: April-19-20 11:15 AM To: [email protected] Subject: Re: [digitalhobbyist] #MISC Pulleys? ? How does a toothed belt provide higher accuracy than a round belt between the encoder and spindle? ?Assume high quality bearings and essentially zero friction at the encoder side. ? A timing belt is ideal, but in my case it wasn’t a good option and the round belt has been working well including with thread cutting. ?A timing belt for me either would have added the lash and noise of a gear train or would require making a custom two part pulley that clamped around the narrow part of my spindle — that would potentially also add inaccuracies. ? ? ? alex From: [email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...> ? There is no way I would ever use a flat or round belt to drive an |
开云体育That’s the test that I did John. I left it running for an hour and alignment was still good. ?Overall I think the accuracy is better than when running with a many stage gear train. ?It’s a lot quieter too.
This doesn’t account for any per revolution noise. For instance an ovalized pulley could have the same circumference and match after days of running, but would create bad threads. ?I did see this when I first made my belt and it
had bump where the belt was welded. ?
I’m open for ideas on how to do a timing belt on my lathe. I thought through a lot of options, but didn’t come up with anything that wasn’t a lot of work (like a two piece pulley or shimmed pulley).
alex
alex
From: [email protected] <[email protected]> on behalf of John Dammeyer via groups.io <johnd@...>
Sent: Monday, April 20, 2020 9:04:12 AM To: [email protected] <[email protected]> Subject: Re: [digitalhobbyist] #MISC Pulleys? ?
Perhaps do an experiment for all of us. Here's the premise. ? As long as the two pulley V grooves are identical in shape and depth and the same diameter of course and the belt is the same diameter over its entire length the encoder and the spindle should stay in sync. ? So with the lathe stopped place a ruler along both pulleys aligned with the center of each pulley axis and draw a line on each pulley from the center in the direction of the other pulley. ? Now if you were using toothed belts months/years later when you turn the spindle by hand until the lines point to each other a ruler will show they still line up. ? The question is, over a few minutes, hours, days will the lines on the non-toothed belt pulleys still line up?? ? If they do you won't have slippage. If they don't and it's in the minutes or hours then you can't trust their position accuracy. ? John Dammeyer ? ? From: [email protected] [mailto:[email protected]]
On Behalf Of alexphredorg ? How does a toothed belt provide higher accuracy than a round belt between the encoder and spindle? ?Assume high quality bearings and essentially zero friction at the encoder side. ? A timing belt is ideal, but in my case it wasn’t a good option and the round belt has been working well including with thread cutting. ?A timing belt for me either would have added the lash and noise of a gear train or would require making a custom two part pulley that clamped around the narrow part of my spindle — that would potentially also add inaccuracies. ? ? ? alex From:
[email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...> ? There is no way I would ever use a flat or round belt to drive an |
开云体育I'm guessing from this photo that the large driven step pulley comes off. That means it would be relatively easy to bore a hole in a larger diameter toothed pulley that allows you to place it right where you have your rubber belt.? And use an identically sized pulley on your encoder. ? So I believe it's possible but if what you have is working and you are happy with the results then leave it.? John ? ? From: [email protected] [mailto:[email protected]] On Behalf Of alexphredorg
Sent: April-20-20 9:15 AM To: [email protected] Subject: Re: [digitalhobbyist] #MISC Pulleys? ? That’s the test that I did John. I left it running for an hour and alignment was still good. ?Overall I think the accuracy is better than when running with a many stage gear train. ?It’s a lot quieter too. ? This doesn’t account for any per revolution noise. For instance an ovalized pulley could have the same circumference and match after days of running, but would create bad threads. ?I did see this when I first made my belt and it had bump where the belt was welded. ? ? I’m open for ideas on how to do a timing belt on my lathe. I thought through a lot of options, but didn’t come up with anything that wasn’t a lot of work (like a two piece pulley or shimmed pulley). ? alex ? alex From: [email protected] <[email protected]> on behalf of John Dammeyer via groups.io <johnd@...> ? Perhaps do an experiment for all of us. Here's the premise. ? As long as the two pulley V grooves are identical in shape and depth and the same diameter of course and the belt is the same diameter over its entire length the encoder and the spindle should stay in sync. ? So with the lathe stopped place a ruler along both pulleys aligned with the center of each pulley axis and draw a line on each pulley from the center in the direction of the other pulley. ? Now if you were using toothed belts months/years later when you turn the spindle by hand until the lines point to each other a ruler will show they still line up. ? The question is, over a few minutes, hours, days will the lines on the non-toothed belt pulleys still line up?? ? If they do you won't have slippage. If they don't and it's in the minutes or hours then you can't trust their position accuracy. ? John Dammeyer ? ? From: [email protected] [mailto:[email protected]] On Behalf Of alexphredorg ? How does a toothed belt provide higher accuracy than a round belt between the encoder and spindle? ?Assume high quality bearings and essentially zero friction at the encoder side. ? A timing belt is ideal, but in my case it wasn’t a good option and the round belt has been working well including with thread cutting. ?A timing belt for me either would have added the lash and noise of a gear train or would require making a custom two part pulley that clamped around the narrow part of my spindle — that would potentially also add inaccuracies. ? ? ? alex From: [email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...> ? There is no way I would ever use a flat or round belt to drive an |
开云体育The pulley does come off, but the spindle is 44mm where the pulley is mounted and 40mm for the exposed part. That is why I’d need to shim or make a two piece pulley.
That’s not a major project, but when what I have works there isn’t a lot of incentive either.
Alex
alex
From: [email protected] <[email protected]> on behalf of John Dammeyer via groups.io <johnd@...>
Sent: Monday, April 20, 2020 9:35:22 AM To: [email protected] <[email protected]> Subject: Re: [digitalhobbyist] #MISC Pulleys? ?
I'm guessing from this photo
that the large driven step pulley comes off. That means it would be relatively easy to bore a hole in a larger diameter toothed pulley that allows you to place it right where you have your rubber belt.? And use an identically sized pulley on your encoder. ? So I believe it's possible but if what you have is working and you are happy with the results then leave it.? John ? ? From: [email protected] [mailto:[email protected]]
On Behalf Of alexphredorg ? That’s the test that I did John. I left it running for an hour and alignment was still good. ?Overall I think the accuracy is better than when running with a many stage gear train. ?It’s a lot quieter too. ? This doesn’t account for any per revolution noise. For instance an ovalized pulley could have the same circumference and match after days of running, but would create bad threads. ?I did see this when I first made my belt and it had bump where the belt was welded. ? ? I’m open for ideas on how to do a timing belt on my lathe. I thought through a lot of options, but didn’t come up with anything that wasn’t a lot of work (like a two piece pulley or shimmed pulley). ? alex ? alex From:
[email protected] <[email protected]> on behalf of John Dammeyer via groups.io <johnd@...> ? Perhaps do an experiment for all of us. Here's the premise. ? As long as the two pulley V grooves are identical in shape and depth and the same diameter of course and the belt is the same diameter over its entire length the encoder and the spindle should stay in sync. ? So with the lathe stopped place a ruler along both pulleys aligned with the center of each pulley axis and draw a line on each pulley from the center in the direction of the other pulley. ? Now if you were using toothed belts months/years later when you turn the spindle by hand until the lines point to each other a ruler will show they still line up. ? The question is, over a few minutes, hours, days will the lines on the non-toothed belt pulleys still line up?? ? If they do you won't have slippage. If they don't and it's in the minutes or hours then you can't trust their position accuracy. ? John Dammeyer ? ? From:
[email protected] [mailto:[email protected]]
On Behalf Of alexphredorg ? How does a toothed belt provide higher accuracy than a round belt between the encoder and spindle? ?Assume high quality bearings and essentially zero friction at the encoder side. ? A timing belt is ideal, but in my case it wasn’t a good option and the round belt has been working well including with thread cutting. ?A timing belt for me either would have added the lash and noise of a gear train or would require making a custom two part pulley that clamped around the narrow part of my spindle — that would potentially also add inaccuracies. ? ? ? alex From:
[email protected] <[email protected]> on behalf of Richard via groups.io <edelec@...> ? There is no way I would ever use a flat or round belt to drive an |
