Flat belts

As usual I'm sure someone will know the answer. Yesterday a joiner friend of mine asked me how to close the crocodile clips when shortening a flat belt in order to keep the adjustment, as he's just acquired a large wood turning lathe which has a flat belt from the motor to drive the spindle, which is a bit on the sloppy side. He seemed surprised that I didn't know, I explained that by the time I entered engineering totally enclosed V belts were pretty much the accepted thing. I suggested off the top of my head that they might have to be hammered shut, but I suspected the best option would be closing them under a press, as I said, I expect someone will come up with the definitive answer.

If they're the sort of clip with a joining pin across then the instructions that I had suggested squeezing the teeth into the belt in a vice with the two halves of the connector joined by the pin. The danger of doing each half separately is that you then cant get the pin in, and have to take it apart and start again. I don't think the clips take too kindly to repeated removal and re-fitting, they usually come in a longish length and you cut off enough to do the belt.

Having got the clips onto the belt then you beat them down with a hammer and block as needed to get as smooth a joint as you can.

Totally agree with Keith, when I were a lad I watched the injinere doing exactly that sometimes with a vice held by an assistant to join the belt in place if it was easier than having to dismantle 14 foot flywheel pulley or the lineshafting.

There's actually a special tool for it, well probably several.

I was hoping to find a good on-line photo to link to, as the one I have in the cellar is suffering from a water leak a few years ago. I couldn't see anything much via Google images, so you'll have to make do with some snapshots of my rather rusty

Mastabar Belt Lacer.

If anyone needs a better quality photo, I can probably supply something higher quality another day, when I've given it a good wire brushing.

Paint will have to wait until much later.

If you're near Sheffield and need the use of one, just let me know.

Edited By peak4 on 17/04/2016 22:16:02

Edited By peak4 on 17/04/2016 22:16:34

Edited By peak4 on 17/04/2016 22:16:50

Hi Mick, flat belts for machine pulleys were usually joined with the wire type clips in the photo below and as peak4 has shown, were closed in a tool in his photos.

The tool in peak4's photos however, was probably a more expensive one. Mastabar also did a simple machine like the one below.

In this one you could do four different sizes. You simply cut off the required number of clips needed for the width of the belt, bearing in mind that each group of clips at each end had to be offset so that the ends of the belt would be in line with each other. You would then load up the clips for one end into the correct set of slots, first by removing the pin with the eye on the left hand side and then putting in the clips and replacing the pin back to retain the clips in the correct position. With a bit of experience and if the width of the belt would allow, you could do both ends at the same time.

Once you had all your clips retained, you would rip all the paper out that holds the clips together for loading into the tool. You would then push the belt end into the open clips as far as it would go and then close the hinged part of the tool whilst keeping the end of the belt in place.

Then when you were ready, you would clout the hinged part with a big hammer and one end would be done, you just repeat the process for the other end, remembering to offset it in the correct direction. The tool in peak4's photos would be the same procedure, but of course you don't need a big hammer.

Regards Nick.

P.S. instead of offsetting each end, you can also use one less clip in one end and the belt ends would be placed in the centre of each group of clips.

Edited By Nicholas Farr on 18/04/2016 00:26:30

How big is the belt? Your joiner mate might be better off to scrap the old belt and fit an endless Poly-V belt, as used for car alternator drive belts etc.

I run these on the the old flat belt pulleys on my Drummond lathe and am very pleased with the result. Far superior to the old leather belts or the more modern nylon with leather lining flat belts.

Small lathe sized belts, e'g 1" wide can be sewn together using copper wire and an awl . I did ones years ago and it lasted several years in a hobby enviroment. Another way is an old car timing belt running on the back of the belt.

On my 1929 vintage lathe I've simply scarfed the ends to give about 25mm overlap and glued together using PVA wood glue with the joint clamped between two pieces of metal. So far it's lasted 2 years of regular use with no signs of letting go, but then i don't run a lot of tension on my flat belt out of respect for the age of the bearings in the headstock. The low tension also provides a good safety feature if something goes wrong, as the belt will slip long before any damage is done.