The Mens shed has a 7.5HP motor with a 3 step (large diameter is 265mm) flatbelt pulley on it and they asked me If I would sell the motor. I thought it would be more saleable with the pulley take off so I said I would do it.

I removed the bolt that was holding the key in place and the key fell out Great, I though this is going to be easy
As you can see I had good side access to the pulley so I got my biggest wooden mallet made of Rock Oak and gave it a number of fair whacks while rotating the pulley.
The striking sound was like a large gong, but ZERO movement, AND I completely destroyed the mallet!
Original.jpg

So I decided to make a puller using some 12mm steel plate and 1/2" all thread rod.
Also Poured some diesel into the cavity above the shaft and left it ON.

Pulley.jpg
BUT again not even a squeak of movement.
Heated it with a MAPP and propane torches - nothing.
One issue I identified was that the big pulley is hollow and the main boss is inside that so it was very difficult to get heat direct onto the main boss.
I could just poke the MAPP torch up between the back of the pulley and the motor but didn't want to leave it in there too long as I was worried about overheating the motor.
What that photo doesn't show is how mangled/bent the all thread rod ended up - basically unusuable.

At this stage I decided to use my press.
Now the stand on my press is too short to fit the whole motor under so I firstly had to lengthen it.
Fortunately I had some HD 2" galv water pipe handy.
I set it up so the big pulley straddled those wooden blocks and cranked on the pressure.
At around 8 tons and heating with the MAPP and propane torches the outside of the big pulley emitted a mild crack and snapped off the boss.
SNappedPulley.jpg
Well I thought, now I can at least apply heat direct onto the boss.

I rang my Al boat builder Boilermaker/Welder BIL and he came around with an angle grinder with a 125mm tungsten carbide tipped saw blade especially made for chewing Al and he cut some vertical slots in the boss but of course he could not cut them all the way through to teh shaft or down to the base of the boss. It's slightly terrifying to watch him use it as tiny shards of very sharp Al go everywhere. He was fully PPEd while doing it - he uses this sort of gear all the time at work.

This morning made a custom boss/pulley support (S in photo below) from some 125 x 75 x 12 mm angle.
Support.jpg

At around 9.5 tons while heating with the MAPP/Propane torches there as a medium BANG and the motor moved down a couple of mm.
Then after that about 2 tons was need to fully remove the boss.

Below you can see how clean the shaft is - so not corroded.
It even looks like some diesel got down there.
The chewed side of the boss was done so the boss could nestle closer into the side of the support and be more directly under the press.
Boss1.jpg

Here you can see how large the Boss is.
The bore size is 35mm
Boss2.jpg

I reckon I've spent 20 hours on this.
Attached Images




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