Thread: bandsaw is suddenly bogging down - help!

Drive belt?

I just went out and had a look. I don't know the name of it but it looks to be made of nylon, and has three ridges that fit of course into three grooves on driveshaft and lower wheel.

The back ridge of the belt is ever so slightly worn. Could that be the whole problem? Seems like a fairly small departure from normal to cause such a large change in performance.

Dave

I would check the drive belt as suggested , if that is not excessively worn / stretched, then I suspect that the motor is in need of some TLC.

I have a suspicion that the carbon brushes may be worn, this means that they probably have enough length to run the machine , in a no load situation, however under load they do not have sufficient pressure on the commutator to transfer the current to windings,.

Jeff
vk4

How do I check the motor? I've got no experience pulling apart motors or electrical devices.

Dave

I guess you should send it to a qualified workshop. However over the year I have opened up many power tools and cleaned the commutator and refitted new brushes. It is not rocket science and quite safe if done on a bench with the power cord disconnected. I haven't repaired an electric motor as such but the principal should be the same. Good luck.

Whitewood

Did you also check the the drive belt was sufficiently tensioned as well and that it isn't slipping? At a guess I would imagine it should only have about 5mm to 10mm deflection when pressed with your finger.

Pretty sure that you'll find that the motor in your machine doesn't have brushes in the motor.

Yeah I checked the tension - and you're right, it was abouta smidge less than 10mm deflection with a moderate finger push.

I'll try and check for any brushes.

INDUCTION , motors without brushes , are generally used for machines , such as bench grinders.

Motors on ,saws , lathes ,pedestal drills etc, are generally a brush motor, this has to do with weight, and costs in manufacturing, it has only been in the last couple of years that I have seen/heard of , panel saws and the like being built with INDUCTION motors.

If you do not feel confident to disassemble the motor , TAKE IT TO A TOOL REPAIRER,
for a moderate fee they will check the motor and quote on repairs.

My 2 cents worth.

Jeff
vk4

Maybe a silly question but.... the other blade that you tried... the one that was cracked... was it new or 2nd hand?

I've only ever used new blades. It was second hand in the sense that I used it for a while, stored it then got it out again, but only I have used it. I might have got stepped on or bend in the drawer or something. The importsnt point is the current blade is fine.

I just tried to take the motor apart to check the brushes. On the back of the motor there's a cage that encloses an impeller that colls the motor, mounted on a shaft that must run right through the motor. I took the cage and impeller off. Then I took three bolts out that hold the plate that's on the back of the motor plate on. This plate came out about 1/4 inch and would come no more. It spun almost as if it was on a bearing. So I put the bolts back in.

I went to the front of the motor, where there are three screws holding the front plate on. I could not get them undone. I stopped trying so I didn't ruin the head of the screws. I put it all back together, and am thinking I will take it to the washing machine repair man or something in Fyshwick.

Is there somewhere else in Canberra that people would recommend? I sort of need it back up and running ASAP.

Dave

It's alright, everyone can stop panicking.

It's working again. The solution is a little embarassing, but I will out with it because this may happen to others.

Where I thought 10mm drive belt deflection was tight enough, turns out it was not. After reassembling the saw, I really tensioned the drive belt up. I leaned hard on the motor before tightening up the last bolt. 5mm of belt deflection.

Now it's back to chewing through ironbark with little trouble, tight corners, fast feed rate, no problems.

Thanks for all the ideas and whatnot, it is much appreciated.

Dave

DJ Wins (acco)
Very first post, got it in one.
Good to hear on track again.

Originally Posted by yeoman

Now it's back to chewing through ironbark with little trouble, tight corners, fast feed rate, no problems.

Good stuff

Get a new belt as I would say that this one is nearly at the end of its life and probably glazed.

Clean the pulleys before fitting it.