RJH Linisher Drive Belt

This is my first post on the forum, so apologies if I've picked the wrong section. I've recently acquired a 3 phase RJH Linisher which works well, save for a slightly (well, actually very) worn drive belt. In the belt's current state I am struggling to measure it up to order a replacement. I wonder if anyone has one of these machines who knows the correct drive belt size / profile, or if not, could offer some guidance on how to measure from the pulleys the correct size to order? I am assuming from the pulley I could estimate the drive belt width and depth and then run string between the two pulleys to give me the correct length. Does that sound right? I am also aware that the belt will have stretched over time. My current belt:

That sounds about right James. As I discovered the other day, the piece of string idea results in a belt that is a bit short.

I wanted a belt for the coolant pump on a Senior Major Mk2 milling machine. Using the piece of string measurement, a 33 inch belt was required but when I obtained one it was clear that a 35 would be more suitable.

You definitely need a new belt!

Brian

Edited By Brian H on 14/07/2020 17:48:07

Hi James

You may find this calculator useful

Belt Lengths and Ratios

The string method can be used if you measure the OD of the pulleys minus 8 mm for "A" section belt.

Calculate both driver and driven diameters. Add together and divide by 2.

Measure the shaft centres and multiply by 2.

Add the Totals of Half Diameters and the 2 shaft centres will give a close approximate belt length

Eric.

Edited By oldvelo on 15/07/2020 03:42:11

If it a Vee belt, dimensions for the belts and pulleys are quoted in various places, such as Machinery's handbook.

That belt is so far gone that it could be a round cord type belt!

If it is/was a V belt, measuring the pulley groove width / depth is the way to go. This will tell you if the belt should be Z, A or B section.

Howard