V belt size.

[davebParticipant @daveb17630]

I bought 2 replacement V belts for my lathe, 1 X B32 and 1 X B33. When I tried to fit them, both were too long. I measured them (inside), the B32 is 34", the B33 is 35". I spoke to supplier on phone, he pulled one from stock and measured it, said it was correct. Seems a bit odd that I could get 2 belts incorrectly marked. I cut off the old belt (B32), it measured about 32 1/2 end to end. Could be me but this doesn't seem right. Just to add something extra to a day which was already going downhill, the single phase motor which has always been reasonably quiet has started resonating with the stand and creating a very loud, very annoying hum, slackening off the fixing bolts on one side stops it but it's not really a solution. Dave

[davebParticipant @daveb17630]

Shouldn’t they be the marked size?

[davebParticipant @daveb17630]

I returned the V belts to the supplier, he telephoned me this morning to say that he had checked the supplied belts and they were within spec. It seems that the Chinese belts are marked with the actual length and the British made items are 50mm longer than the marked length which is because the Chinese measure the inside length and the British measure the outside length (?) Still makes no sense to me but the supplier has kindly sent me 2 replacement belts, B30 and B31 which should fit.

While I've got the thing in bits, I may as well fit the 3 phase motor and inverter, looks a lot easier than sorting out the vibration problem. Dave

[peak4Participant @peak4]

I found this rather helpful page the other day, after reading your first post, but didn't get chance to link to it at the time and then subsequently forgot.

Edited By peak4 on 23/02/2017 16:26:12

[davebParticipant @daveb17630]

Thanks peak4. Page is helpful but describes something that makes no sense to me and obviously not to the Chinese either. I can't see any point in marking something with it's length and then making it a different length altogether. Oh well, we live and learn. I'll hazard a guess that the people who dreamed this up are now employed by the ISO at seven figure salaries with full health and pension benefits. Wait for the new 6mm slot drills that cut 7mm slots. Dave

[Brian OldfordParticipant @brianoldford70365]

There is no mention about Z section (10mm/3/8" wide) belts there. However there is a calculator for them at http://www.beltingonline.com/vee-and-wedge-belts-213/help-identifying-v-belts-591/z-section-592/z-section-standard-600/

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