Small horizontal mill ID, celtic knot logo?

Rainbows,

a bit late, just got home but I'd say u got a bargain........

Clogs

Rainbows

A belt drive version of the conventional small lathe back gear layout works well and isn't stupidly hard to configure. Basically two shaft system. One input/output power shaft and one outrigged shaft to carry the back belt pulleys. I did one many years ago and the only mildly tricky part was sorting out the direct drive / back belt drive selection. I used a pin system like the usual small lathe. These days I'd work a bit harder to sort out a dog clutch. Ordinary Vee belts back in those days. Poly-vee would have made life much easier as being simple to make and able too e much smaller.

Basic system is 4 pulleys two large and two small. Small pulleys drive the large ones. Much easier if they are identical pairs but it can be done with different sizes. Fix one pair together at a suitable spacing and either mount on a free running shaft or sit bearings inside the pulleys and use a fixed shaft. 6 of one, half a dozen of t'other really but overall I figure a fixed shaft is probably marginally easier. Especially if a bit of cut'n try engineering is envisaged.

The other large pulley is fixed to the power shaft and its corresponding small pulley is free running on suitable bearings. Drive goes either direct to the power shaft or to the free running small pulley. I put my basic speed reduction pulley in the middle on a free running bearing and pinned it to either the large pulley for direct drive or the small one for back gear. It worked but was somewhat inelegant and arranging access to the drive pin was bit tricky. Mainly due to not thinking the whole thing through properly in the first place. These days I probably use a dog clutch.

Clive.

Ah thats a good idea, I imagine that a poly vee belt with quite a few ribs can transmit quite a lot of torque. Will have a google around to try and find max torque, and check feasibility.

Well it would kind of work but not well. For 100 RPM on a 50mm pulley the kW per rib is like 0.01-0.02. Don't think 100 rib belts are in common manufacture. If I were switching between a very high speed and a medium speed it would work great but not here.

Edited By Rainbows on 10/09/2017 22:22:00