12 ms·
Ditch the Torch and Use Induction Heat to Break Free Rusted Bolts
- 082349872349872 3y agoMight also be useful in the opposite direction, installing a preheated bolt to freeze up as it shrinks?
- millebe 3y agoThis wouldn’t work. The primary reason heating and cooling bolts works for their removal is because they expand anisotropically due to constraints and then shrink uniformly. If you remove a bolt in this way and measure it with a micrometer, you will find the cross section has permanently narrowed and the bolt has permanently elongated, an ever so slight amount. Assuming you managed to install a preheated bolt, it would become looser as it cooled down.
- millebe 3y agoNow if you tried this with a hot bolt and equally hot nut, the bolt would contract along its length, but the threads would get looser so it’d probably still be a net loss for clamping load. Rivets, on the other hand, are commonly heated and forged so that both ends have a head, and then as they cool the clamping load increases. This was very common a hundred years ago, but my understanding is that bolted joints provide a more predictable clamping load and that is why they are so dominant today.
- rolph 3y agoperhaps you mean preheated [nut?] this is something ive seen done with new trailer ball being installed. heat the nut and crank it on the ball threading, but not too tight or the nut will crack. >> really the original title messed up a bit. they say bolt, but are clearly depicting a nut as the subject. hot-nut.jpg [JPEG] [https://hips.hearstapps.com/hmg-prod/images/1-0001-hot-nut-64d2849f11595.jpg?crop=0.636xw:0.954xh;0.151xw,0.0459xh&resize=980 https://hips.hearstapps.com/hmg-prod/images/1-0001-hot-nut-6...:*]
- 082349872349872 3y agoyes, my bad; as in TFA's picture
- jaredhallen 3y agoLooks cool, but pretty much only practical for nuts. If a bolt was threaded into anything of size, I guess you could heat up the head of the bolt. Maybe it would transfer down the length of the bolt sufficiently? Doesn't seem likely though.
- jaredhallen 3y agoLooks cool, but pretty much only practical for nuts. If a bolt was threaded into anything of size, I guess you could heat up the head of the bolt. Maybe it would transfer down the length of the bolt sufficiently? Doesn't seem likely though.