physics of a flat belt and pulleys?

[Walter A]

Regarding multiple splices, I ran a few old planers back in the 1960s with leather belts and multiple splices. It was pretty noisy. Also since belt guards were seldom seen pretty spectacular when one let go.
Glad I made it through those times.

 

[fciron]

Um, I didn't buy a leather belt. I bought a Super Grip belt from McMaster. Those have a cotton core and rubber casing on both sides.

metalmagpie

Doesn't matter what you bought or how many times you say it. We're talking about leather belts here.

Did you know they stretch and they have to cut chunks out of them from time to time?

;-)

 

[Joe Michaels]

Metalmagpie:

You are correct about the rings on the lineshafts. These were wire rings that were on the lineshafts to try to prevent a buildup of oily sludge. In a woodworking mill, moreso than a machine shop, the rings helped keep the shafting clean. What is always interesting is how the rings move up and back along the running lineshafting. As the loads on the lineshaft change, so does the shaft deflection and the rings move accordingly. Usually, the rings kind of see-saw up and back along the line shafting, but as machine tool loads come on and off the lineshafting, the rings really get to moving along the shafting. It's an interesting indicator of how the shafting reacts to changing loads.

 

[john.k]

Ive got a Jones and Shipman drill with the flat belt drive turns round the corner from the back cone speed change ,to spindle ......several people have told me "it wont work ,its impossible"....but it does work.....the strange thing is it only works in one direction.....in the opposite direction ,the belt just falls off........and the other strange thing is the spindle drive is self tensioning,it climbs up the pulley to about half way,by which time its quite tight....and easily drives 3/4 drills in steel.......came from the Qld railways wood shop,not a mark on the table ,as it had a thick block of wood bolted to it....cost $1 on tender ,and had a Rohm chuck,which the railways guy loading it stole......Right in front of me.

 

[SAG 180]

So ideally the belt material has some stretch and wider than it is thick, round or square cross section belts won't work on a crowned pulley.

 

[john.k]

One thing millenials cant grasp with belts,is running belts crossed over.....this was once very common in woodworking for two reasons....it increases the pulley contact ,and it makes the belt self cleaning in heavy woodchips or sawdust.