Posted by Greg Coffin [172.68.34.45] on Saturday, April 13, 2024 at 21:03:47 :
In Reply to: Bolt removal in aluminum housing, need help posted by Greg Coffin [172.68.34.47] on Friday, April 12, 2024 at 13:05:30 :
Thanks for the feedback guys. I was able to get all the bolts out yesterday, using various methods.
Two of the bolts came out using the welded nut method. The key seemed to be to moderately heat the casting and work the bolt back and forth. After welding the nut to the bolt, I could feel the slightest movement with gentle pressure on the wrench. Heating the casting allowed the bolt to back out more and more, then I had to reheat the casting. The first bolt came out in 5 min, the second took about 15 minutes. The threads in the casting cleaned up pretty good with a 1/2" tap. The threads in the second hole are a little rougher, but still serviceable.
The last bolt was an ordeal. When I drilled the bolt the hole was not centered, which came back to haunt me. I enlarged the hole as much as I could without nicking the threads. Then I used a metal blade for a saber saw and a handle adapter and slotted the inside of the bolt from the center toward the threads, slots at 90 deg to each other. I got a quarter of the bolt removed with a punch, then I slotted the remainder of the bolt in half and collapsed it with a punch. As I cut the slots I could see when I got to the root of the threads, so I didn't damage the casting. It took about an hour+ to do the slotting, but it worked.
My backup plan was to bolt a steel plate to the winch and use a mag-drill to bore out the hole, and hopefully save the threads. If not, a Helicoil would be used to restore the threads. I'm glad I didn't have to go that route.
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