Measuring a V-Belt for an old Wood Lathe

[Lionelgee]

Hello All,

To get the correct sized V belt for a wood lathe do you just get a dress maker's tape measure and measure around one set of in-line pulleys? Or do you subtract or add a rule of thumb measurement to ensure V-belts are tight or loose enough? If so what would the addition or subtracted amount be?

I just bought an old no name brand wood lathe for a economical price from a local auction place = in as is condition. The lathe did not come with a V-belt. Any belt measuring tips and tricks would be greatly appreciated.

I will finish my cup of tea and go outside and examine the lathe more closely to look for a possible name manufacturer and take a measurement or two.

Kind regards
Lionel

[Slunnie]

The measurement is on the outside of the belt. Even if you're out by a little bit, you can tension or loosen the belt with that setup. Usually the motor swings with the weight of it causing enough load for the belt to grip.

[Fluids]

… and is it an A or B section belt is the second question ?

You can google the section sizing but if I remember correctly A is 1/2” and B is 5/8” measured across the back of the belt … the belt drives off the walls not the inside face … and again iirc use a piece of cord/string to measure around the valley of your two pulleys and add 1” for A section and 2” for B section.

Kev..

[p38arover]

A mob selling belts may have a belt measuring jig. I remember seeing one at KLR many years ago.

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[JDNSW]

Just add to that, all belt installations will have some way of adjusting tension. If, as suggested, this uses the weight of the motor to tension the belt, you need to prop it up to at least half the range of movement before measuring.

If it is unclear how your lathe belt is tensioned, perhaps some pictures would allow some of the experts here to help!

[Lionelgee]

Hello All,

Some torch light explorations revealed GMF Betts Electric Motors James N. Kirby. Still looking for the model number. Hopefully daylight will reveal it.

From some subsequent research it looks like it requires a 6 mm diameter round poly belt made in Australia.

GMF were an Australian company. From some of the auctions of similar GMF lathes my lathe could have been made in 1988.

I bought the lathe mostly for the bed. I was surprised to find out that the motor still works very nicely.

I got side-tracked by a chore, so I did not have much time to seek model numbers this afternoon, as first planned.

There is an Australian retailer of the replacement belts advertising on eBay ...https://www.ebay.com.au/itm/276436429457.

I might have just landed on my feet with the purchase of this lathe!

I will keep this post updated as I find out more.

Thank you everyone for your contributions - they are much appreciated.

Kind regards
Lionel

[p38arover]

Back in the Eighties, I used to race model boats. To start them, I used a round poly belt around the flywheel and driven by a hand-held starter motor.

I used to buy the poly belt off a roll, cut it to length, melted the ends over a gas flame, and then pushed the ends together. Then, with a sharp blade, trimmed off the excess melt.

The joints never failed.

[BradC]

I used to buy the poly belt off a roll, cut it to length, melted the ends over a gas flame, and then pushed the ends together. Then, with a sharp blade, trimmed off the excess melt.

The joints never failed.

No, that's pretty much the textbook method for joining a poly belt, although these days usually with an incredibly expensive jig and heater.

[Blknight.aus]

For an a section belt.

Set the tensioning system just under half way so it reads a shorter belt) using some 13mm rope run the belt.path and then join the rope somits almost correctly tensioned.
Remove and take it to a bearing, power transmission or farm general store. They will put itnon a belt measuring tool, it will likely.come.up between 2 sizes get the smaller one.

If it's b section set the tensioner to just over half way.

Most places will be understanding if you bring back the belts unused because the adjustment was wrong.

Typically the correct adjustment for the belts I'd with the tensioning system at the first 1/3 point of travel.

I check with a deflection measurement of 3x the belt depth at the center of the shortest run.

[scarry]

We go to the bearing shop,as they sell belts.

Give them PCD of both pulleys,and adjust motor until center of adjustment.
Then measure distance between center of shafts.

That should be pretty close.

Obviously knowing section of belt,Z,A,B,SPA,etc,also helps.