Why induction heat bolts?

I

Iron Filing

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Hello,
I was browsing online and came upon induction heaters for bolts . The induction heater is advertised as being able to help you heat bolts so that you can unscrew them.

Now heating something up generally expands it's size. Therefore, it seems to me that heating up a bolt would only make it more difficult to screw in or unscrew.

So, what am I missing?
Why induction heat bolts?

Thanks!
 
Expanding the diameter of a bolt will help break the corrosion; possibly allowing your favorite flavor of penetrating oil to act a little faster. You get the same effect heating fasteners with a torch. Inductive heaters would be safer around flammable stuff.
 
Iron Filing said:
Hello,
I was browsing online and came upon induction heaters for bolts . The induction heater is advertised as being able to help you heat bolts so that you can unscrew them.

Now heating something up generally expands it's size. Therefore, it seems to me that heating up a bolt would only make it more difficult to screw in or unscrew.

So, what am I missing?
Why induction heat bolts?

Thanks!
Click to expand...
When I was wrenching, I had one.
Used on exhaust nuts at the manifolds, much safer than a torch that close to undercar insulation.
Helps soften threadlockers that manufacturers and idiots use.

Also, a 3/8 x 4 bolt with a nut on the end, you can hold the head with the nut red hot.
 
When I was a pro on the heavy tracks, I kept a big butane torch in my kit. Easier to put a li'l heat on it than to damage tools, equipment, and self by reefing on a bar. When the 12k hydraulic impact doesn't break it loose, heat always does.
 
Iron Filing said:
Hello,
I was browsing online and came upon induction heaters for bolts . The induction heater is advertised as being able to help you heat bolts so that you can unscrew them.

Now heating something up generally expands it's size. Therefore, it seems to me that heating up a bolt would only make it more difficult to screw in or unscrew.

So, what am I missing?
Why induction heat bolts?

Thanks!
Click to expand...

It's not the heating in and of it's self, it's the differential heating. If you're freeing up frozen stuff, you heat from the "outside" to loosen the joint. Sure the inside gets pretty hot, but the outside might be glowing red.

Or simple heat cycling to break up the rust/corrosion. Heating a bolt head on a bolt that's screwed into something is a recipe for disaster. But heating said bolt, then letting the whole assembly cool can be enough to break up the rust just enough for you to get a little wiggle out of the bolt, at which point time and patience will get it to come out the usual way, instead of in chips and pieces.

Torches and fire are the "usual" method. Induction heaters are just another method of the same practice. They have been a spectacular tool, because they are controlled, there is no flame, and the heating mechanism (black magic) is very good at heating preferentially from the outside of whatever you put it around. You can (with a good handle on how they work, how heat flows, etc) you can use them to heat things that you wouldn't dare go near with an open flame. They are very much a niche tool, but in terms of cost, risk, maintenance, safety gear, training/knowledge/skill, they're very approachable if that niche might fit into a home shop where maintaining torches isn't practical. Or a hobby shop. Or for a different use, and with a good sense of humor (you'll burn up a few leads learning), you can heat small round rod red enough to hand bend custom shapes and such. Loosen stuck nuts and bolts. Warm metal to remove stickers. All kinds of uses.

Overall they're quite a useful tool, but realistically the chances are that whatever you're doing, they're gonna bail you out big time now and then, and make your day here and there, but they'll probably spend most of their life in the case.
 
As always , sometimes heat works , sometimes it don't . That's why we have torque extenders . Map gas / oxy / etc ...................when it's stuck , it's stuck ! Its what keeps us guys in employment . :)
 
We have an inductive heater at work, use it quite a bit. Doesn't cause cars to be giant balls of flame so It has become my go to for stuck parts, torch next. With the torch you can be assured that it cant be stuck if it's liquid. :cool: Spendy but worth it.
 
Another bonus is there's a strong self-regulation in steel.

Below red hot, magnetic steel has two loss mechanisms: eddy current heating AND magnetic hysteresis losses. Above red the crystal structure flips and it becomes non-magnetic. That means MUCH slower heating.

Sent from my SM-G715A using Tapatalk
 
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