Thread: which pulley moves

I'm not sure what you mean but you shoud not have to undo any grub screws to change speed. Any chance of a pic or sketch?

If the motor and main drive are fixed pulleys the saw only has 1 speed.

Dunno why they bothered with a step pulley as an idler, maybe a previous owner fiddled with the machine.

Yep sounds like an after market addition to me. Doesn't matter which step is used on the idler, it wont change the speed.

Agree or they make two types one two speed and one single speed but use the same motor pulley assembly for both and possibly other machines as well. cause mass production means just that

Rgds

i took a pic and pulled the top pulley off looks like thats the one that can be moved (oops forgot to upload it) now i just need a motor ( what size should i go for 1hp??????) the old one is 3 phase

I've never had one of these BS but normally in an adjustable speed setup there is opposing stepped pulley. So for the to pulley I would think there should be a four step pulley mounted around the other way to the one on the bottom.

The problem with oving the top pulley all the time is that generally machinery is never designed like that. One would think that if the pulley was designed to move then there would be a retaining washer on the end of the shaft to stop the pulley from sliding off in case the grub screw wasn't tightened.
I have a feeling that this may be an aftermarket mod that someone has put on the machine and maybe it should only be single speed. The other reason I thknk this is that at best it would only have two speeds not four and I don't think any of the commercial machines have idlers on them as well.

I would think to get rid of the 4 step pulley and replace it with a suitable single pulley. Maybe a member with a similar machine could gie you some sizes?? But don't throw the 4 step pulley out as they are worth a bit to buy brand new. I just got two 5 step puleys for my lathe at around $80 each. Lucky I have access to the work account still

AFAICT, that's almost identical to my beast, except mine's had more TLC. A lot more, I'd say. Mine doesn't have a stepped pulley, the lower one is a slightly smaller version of the top one... driven by a 1PH heart. It's completely original, apart from a set of roller guides and a new tyre.

At a guess, I'd say someone's done a motor transplant (a 3PH with higher RPM) and went fossicking around in their scrap pulley bin until they found something to bring the speed back to something more usable. I doubt variable speed was a consideration at the time.

With only one stepped pulley it was never designed for variable speed. You'd need a fa fa fa fairly large amount of adjustment to tighten the belt with the setup you have.

Even on generic B/Saws, if they have multi-speed pulley arrangements, there's normally a belt tensioning knob which one releases, move the belt and re-tension. Two minute job, max.

i guess its not realy a problem unless blade changes are neccessary but at least it is possible . it appears that the top pulley can be moved sideways to cover all options the idler has plenty of room to go up and down . the motor end i can adapt to move if needed with a bit of imagination

G'day Tanii51,

Your b/saw is the same set up as mine, or looks to be anyway and mine has three speeds depending on what I want to cut etc.

I know your frustration of undoing the screws to change speed, so tomorrow what I'll do is take shot of the modification I made to make both replacing the pully with a new one and changing speeds much easier.

Hmmm some tinkerer has add a 351 clevo crank pulley from a Fairlane!

thank waldo much appreciated and harry where there a will there a way ( hmm a ford powered chevy fan )

G'day Tanii51,

Ok, here's the shots of my b/saw mod.

The first pic shows and I think this is what you are talking about, previously I had to loosen the screws to this member to either replace the pulley or change the cutting speed.

Pics 2 and 3 show the modification, a 1/4" steel plate which is welded to the b/saw frame which now acts as a hinge to which the 1HP motor is now bolted to. The weight of motor and the steel plate give more than enough weight to keep the pulley fully tensioned.

Hope his has helped you out.