In The Shop: Fire Is My Friend
Oct 21, 2011
I was trying to get a big hub off a tapered shaft. I was in a hurry, the customer was in a hurry, and I didn't have time to use any sophisticated mechanic tricks. I tried a gear/wheel puller, and had applied what felt like several tons of torque to the puller without budging the hub. The customer looked a little concerned as I drug my acetylene torch hose out of my service truck. I handed him a water-filled fire extinguisher and told him to put out any fires that developed, and applied heat to the hub. I had barely burned away all the paint from the center of the hub, hadn't even got it to dull red, when there was a loud "bang" and the hub popped free and nearly fell off the end of the shaft.
I looked at the customer and he said, "Now, THAT was impressive." We finished removing the hub, made the rest of the repairs, and he was soon back in the combine combining corn. Everybody was happy, and once again my torch was the go-to tool that avoided lots of extra work.
Heat is the secret ingredient when it comes to removing stubborn gears, pulleys or hubs from shafts. I usually start with a gear puller, 'cause sometimes I get lucky and things come apart with merely the puller. But if the components turn stubborn, I put a fair amount of torque on the gear puller and leave it under tension while I apply heat to the gear, pulley or hub.
If the gear, pulley or hub has a straight-bore, it can be a slow process, where I heat, then crank on the puller, then heat some more, then crank on the puller. Straight-bores often require significant heat and patience to pull things apart.
Tapered-bore assemblies, however, are almost fun. Nine times out of ten, if you put a lot of tension on the puller, all you have to do is get the gear, pulley or hub warm to the touch and there will be a bang or pop and things are ready to take apart nearly by hand.
So, if you're using pry bars and hammers to try and pound or drive a gear, pulley or hub off a shaft, put down the hammer, install a puller, and apply heat to the focus of your frustration. Fire, or more specifically, "heat" can be your best friend when metal components refuse to separate.