understanding timing belt specs.

[Anthony KnightsParticipant @anthonyknights16741]

I currently have a belt drive on my lathe which uses a timing belt marked 1.5 x 100. The 100 refers to the number of teeth on the belt, but I am unable to match the 1.5 to any dimension relating to the tooth size or pitch. To confuse the issue, all the pulley/belt suppliers I have looked at on the internet specify their products by tooth pitch. Can any body help me to match the 1.5 figure to a tooth pitch so I can order a new pulley. The other alternative is to just order two pulleys and a belt of about the right size and change the lot.

Thanks in advance Anthony.

[Anthony KnightsParticipant @anthonyknights16741]

[bernard towersParticipant @bernardtowers37738]

try googling toothed belt specs there's a lot of info on there

[KWILParticipant @kwil]

Looking at your albums, it appears your lathe is a Clarke cl300m, is this correct?

[Michael GilliganParticipant @michaelgilligan61133]

I can’t remember the exact explanation, Anthony … but the strange specification of your belt has something to do with circular pitch.

There was quite a recent thread here which mentioned it.

MichaelG.

Edited By Michael Gilligan on 18/10/2022 13:09:04

[JasonBModerator @jasonb]

Many of the imported machines use a "module" type pitch so yours is likely to be 1.5 x pi = approx 4.7mm pitch. The chinese web shops may well have them.There is a seller called Ali who will send it Express delivery for a few quid

My X3 for example uses a 2×65 which is 6.3 pitch x 65T

Edited By JasonB on 18/10/2022 13:12:30

[peak4Participant @peak4]

Posted by JasonB on 18/10/2022 13:09:58:

Many of the imported machines use a "module" type pitch so yours is likely to be 1.5 x pi = approx 4.7mm pitch. The chinese web shops may well have them.There is a seller called Ali who will send it Express delivery for a few quid

My X3 for example uses a 2×65 which is 6.3 pitch x 65T

Edited By JasonB on 18/10/2022 13:12:30

Here you go, this site suggests a 4.71mm pitch, which seems to be 1½ mod
https://www.zzr-parts.com/modulus-synchronous-timing-belts/1-5-x-100-teeth-replacement-drive-synchronous-timing-belts/

Bill

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 18/10/2022 13:08:38:

I can’t remember the exact explanation, Anthony … but the strange specification of your belt has something to do with circular pitch.

[…]

.

Sorry … I was in a hurry and didn’t express that very well

What I meant was:

the strange specification of your belt has something to do with it not referencing circular pitch

MichaelG.

[Anthony KnightsParticipant @anthonyknights16741]

Well thank you people for your contributions. I have now established that the 1.5 figure means a tooth pitch of 4.7mm. I also have links to suppliers of belts with this pitch. I did say in my original post, that I was after some different sized pulleys. I have been back on the internet and cannot find any suppliers of pulleys with this pitch. Plan "B" is to order 2 pulleys + a belt with a 5mm pitch. Plan "C" is to turn a flanged bush to fit the motor spindle and attach an existing pulley I have, after boring it out. I'll try plan "C" first as it will be cheaper.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Anthony Knights on 19/10/2022 09:02:02:

.

I have been back on the internet and cannot find any suppliers of pulleys with this pitch.

.

I suspect this standard is the Betamax of the toothed-belt world

MichaelG.

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