Thread: Getting some bearings onto a shaft

For belt tightness there is adjustment built into the motor mount. Still not enough, though. I can confirm the outside measure of the belt is 585mm, so I’m thinking the belt is probably too wide for the pulleys and thus probably sits closer to the circumference of the pulley then it should.

The pulley doesn’t have a shoulder so drilling and tapping is out. Any other suggestions just to get me through the Xmas period? Epoxy cementing it on, perhaps, would that do?

In the new year I will buy a better pulley.

Just read your last post. The belt shouldn't sit on the inside diameter of the pulley, it's driven by the friction on the sides. You can drill through the body of the pulley, you don't need a flange. If using a cut off bolt as a grub screw a high tensile one would be preferred.

Originally Posted by Arron

For belt tightness there is adjustment built into the motor mount. Still not enough, though.

I assume the adjustment is slots in the motor mount - can these be extended, filed out a bit longer?
Some photos would help/.

I can confirm the outside measure of the belt is 585mm, so I’m thinking the belt is probably too wide for the pulleys and thus probably sits closer to the circumference of the pulley then it should.

The pulley doesn’t have a shoulder so drilling and tapping is out. Any other suggestions just to get me through the Xmas period? Epoxy cementing it on, perhaps, would that do?

I doubt it would hold even for a few minutes - and then you would have to get it off cleanly off you wanted to reuse the shaft.
Photo of the pulley would help.

Originally Posted by aldav

Just read your last post. The belt shouldn't sit on the inside diameter of the pulley, it's driven by the friction on the sides. You can drill through the body of the pulley, you don't need a flange. If using a cut off bolt as a grub screw a high tensile one would be preferred.

Originally Posted by Arron

Is there a sneaky Trade-secret fix for this, a way to get an aluminium pulley to grip a slightly undersize shaft and stop slipping?

A few centre punch marks around the shaft. Around the outside centre punch marks the metal is pushed up making the outside diameter of the shaft larger. This works well for shafts into bearings but may not have enough grip for the pulley.

Ok, so I drill straight through the pulley. I’ve never successfully drilled and tapped something before - but nothing to loose I guess.

Re the motor mounts, Bob, the way they work in this case is that one side of the mount articulates around a pin, and on the other side moves in and out along a threaded shaft with a couple of lock nuts. The motor therefore swings in and to the right, and out and too the left. However if it swings very far the belt rubs against the spring tension device of the clutch lever - which I don’t want to butcher because I may one day want to put the motor back into the walking foot sewing machine if my cheapie servo motor gives up. In the sewing machine the belt goes the other way so is not near the spring tensioner.

I can, of course, move the entire motor closer to the shaft using a few blocks of the right size. I was a bit reluctant to do that because it means cantilevering the motor out from the frame. As the motor is very heavy, and the frame is rubbish pine, I don’t see it as a long term solution - but it does indeed look better then my other short term alternatives.

The other alternative is to move the shaft closer to the motor. The only issue there is that it’s starting to be a bit far from the front edge and hence uncomfortable and back strain. Still, ok for a temporary thing.

So tomorrow it’s:
Pull the pulley off, drill and tap a hole for a grub screw.
Drill the shaft to accept the grub screw.
Make some mounting blocks to move the motor closer to the shaft, or maybe shaft closer to motor.
Fit the belt.
And I’m done the motor/electrics side of things.
Surely I can’t screw that up.

Thanks for all your help everyone.

Cheers
Arron

You don't have to drill the shaft, just create a flat on it for the grub screw to tighten on to.

Originally Posted by Arron

Ok, so I drill straight through the pulley. I’ve never successfully drilled and tapped something before - but nothing to loose
Surely I can’t screw that up.

Watch this video and then practice on some scrap.

Originally Posted by aldav

You don't have to drill the shaft, just create a flat on it for the grub screw to tighten on to.

Ok, that is good to know as a flat will give me some vertical wriggle-room.
Thanks

You can also buy a length of link belt that you can customise to your requirement.

I did a bit more work this morning.

This is what it looks so far. I haven’t actually fixed the pulley to the shaft yet as I can’t find a tap and die set.
I’ll be able to remove the three pieces of plywood and attach directly to the frame once I source a right-size belt.
Then I will need to drill the shaft near the top and fit a roll pin which functions as a key to stop the turntable (the actual work surface) from slipping. The turntable will simply have a rather deep half inch hole which slips over the shaft and a couple of slots to engage the roll pin.

Plus I need to rightsize various bolts, nuts and screws where I didn’t have the right size on hand.

The horizontal shaft at the bottom centre is for speed control. It simply actuates on the clutch lever.

Any comments on anything I might have overlooked are welcome.

9DE6F6AB-B2BE-4861-85BE-44AA17750133.jpeg

And here it is with the top on. It’s very heavy which is not a negative at all.

I Still need to cut the splash guard down a bit. Then I need to make a turntable, which is just a simple wood turning job. Finally I need to turn up some ‘bats’ which sit on the turntable and are interchangeable - or maybe buy some modern silicon ones. Then I’m done.

A39631EA-91C8-490F-BCE4-C805204906DC.jpeg

Cheers
Arron

What speed does the motor turn? You need 0 to about 300 rpm on the head of the wheel.

I agree with Pagie re what’s the motor speed. Looks like close to a 1:1 ratio setup at the moment so the wheel will turn at the same speed as the motor. If there’s no speed control on the motor you will need a bigger pulley on the shaft if the motor turns faster than 300 rpm.

There are three methods that you might use.
1 - Take an old bearing and remove the inner race. Use some emery cloth and make the race inner diameter large enough so that it slides easily over the shaft. Put your new bearing on the shaft followed by the inner race. Use a hammer and something like a screwdriver (slot) to drive the inner race against the bearing to seat the bearing where you want it.
2 - With the new bearing off the shaft, put the shaft in the freezer over night. Hopefully the new bearing will slide into place easily before the shaft warms up to ambient.
3 - Take the shaft and bearing to an automotive shop that has the ability to remove and replace (i.e. repair) axel bearings. They probably have the hydraulic ram that can seat the bearing for you.