The Great Bearing Removal Debate Continues
Jun 04, 2015
I've long been a fan of using an acetylene torch to cut apart bearings that won't slide off their shaft. Some of the younger mechanics consider my use of a torch as crude, messy, inelegant and dangerous because of the fire potential. They prefer to use air hammers equipped with pointed or chisel bits to remove bearings.
Their strategy is to insert the pointed bit into the bearing's seal, between the inner and outer race, then hammer and pry to pop that seal out. With the seal removed, they use either the pointed bit or chisel bit to blast one or more of the ball bearings from between the races, then use the chisel bit to crack/break the outer race. Once the outer race is out of the way, they either use a die grinder with a cutoff wheel to surgically cut the inner race so it can be removed, or they use the chisel bit and air hammer to crack or slide the inner race off the shaft.
When it works correctly, the air hammer procedure is quick and clean. But…it is risky. Using an air hammer on hardened steel races creates a high risk of pieces of shattered metal flying around the shop. One of the proponents of using an air hammer neglects to mention that he made a trip to the emergency room after a chunk of shattered bearing race penetrated his safety glasses, the prescription glasses he was wearing under the safety glasses, and lodged in his eye.
There are always safety concerns related to removing bearings, whether you use a torch or an air hammer. The torch risks fire and collateral damage to the machine. Air hammers risk flying shrapnel that can defy safety gear. In my case, I consider the location of the bearing being removed, the risks associated with the different removal procedures, and use the one I deem least likely to do me bodily harm.