Bolt drilling tips (1 Viewer)

[Malleus]

Yes, they are the M8x1.25 square weldnuts inside the frame for the bumper extension brackets. I'm going to replace the weldnuts later, with hexagonal pilot projection nuts.

 

[half k cruiser]

And for anybody that might read this, make your life easier by

1. giving the bolts a good soak in 1:1 acetone atf mixture
2. put the impact on and give them a quick shot to tighten before trying to back them out.

I have had quite a bit of success with the above technique. Usually the only time I break bolts anymore is when I don't have time or tools to do it right.

 

[TossYoda]

Does anyone heat the broken bolts with a oxy-acetylene torch (seconds, 5 or less usually) and spray down with water then turn? I've had some luck with this.

 

[bigredmachine]

What I should have done was add heat and some penetrant to the mix, but because of the plastic part of the headlight was still in the way and I didn't want to melt that and because I was worried about botching the paint, I thought I could cut a corner and that was a bad decision.

even just a little bit of heat can be your friend. if you haven't gotten it out yet can you punch out the bolt and just make it a through bolt instead of a bolt going into cut threads?

 

[Warpigg]

Does anyone heat the broken bolts with a oxy-acetylene torch (seconds, 5 or less usually) and spray down with water then turn? I've had some luck with this.

I have heated things in the past with whatever is available, be it a propane torch(almost useless), a map gas torch or oxy-acetylene. And then I spray with wd-40 or pb blaster or similar product then try to break free what ever I'm working on and if it doesn't break free I heat and spary again and again till it does. I've done this quite a few times doing jeep knuckles since people around here don't use grease... I feel like if you used water you run the risk of hardening the part to much and breaking it. Granted the same could be said when using penatrating oil but oil has been known not to harden things as much as water.

 

[Pin_Head]

Heating definitely helps, but hot hot makes a difference too. If you heat the bolt to red hot (above 1400 F) with OA or MAPP, then the metal shrinks when it cools. This makes them come out easy.

An OA torch is also useful for getting broken bolts, drills, EZ outs and taps out. Turn up the oxygen pressure to 20 PSI and then heat the center of the bolt to red hot and then cut the acetylene and turn up the oxygen to burn out the offending part. If you have a steady hand, it won’t touch the threads. Wear goggles and stand aside because of the back wash.

 

[namsag]

So tell me about the torches. I have been using a propane torch, which sufficed to loosen my rear shock bolts. Is the MAP-Pro any better? Just pulling numbers off the internet, I see propane at 3600*F, and MAP-Pro at 3730*F, not much of a difference, a little less than 4% if my math is right. Does it really make that much of a difference?

 

[Pin_Head]

Don't confuse temperature with heat. There isn't that much difference in temperature between MAPP and propane, but the heat content difference is significant enough to make things like silver solder work with MAPP that don't work with propane. All of them burn much hotter with oxygen.

An OA torch is a versatile tool. Use it as a gas axe, a blue tip wrench, a heater or a welder.

 

[Malleus]

This is a recipe for annealing your frame. This is why I never use acetylene or MAPP gas, it gets too hot for the frame material.

 

[Warpigg]

I've never had to heat a part till it's red hot to get it out or whatever. If I am heating a part that hot I'm probably cutting it off

 

[Pin_Head]

This is a recipe for annealing your frame. This is why I never use acetylene or MAPP gas, it gets too hot for the frame material.

The frame is mild steel and not a hardened alloy so it doesn't anneal. You can weld on it and heat it all you want. Some car bodies are hardened alloy but not the 80 series.

I've never had to heat a part till it's red hot to get it out or whatever. If I am heating a part that hot I'm probably cutting it off

Don't confuse temperature and heat. An OA torch will raise the temperature of the bolt rapidly while the threaded hole in the frame remains relatively cool. Steel shrinks when you raise the temperature above the A1 phase transition temperature (about 1,400 F) and then let it cool. The shrinking makes it come out easy. Heating with a propane torch for 2 minutes puts more heat into the frame than 15 seconds with an OA torch.

 

[bigredmachine]

Is the MAP-Pro any better

map also puts out more btu's so it will heat quicker.

 

[Malleus]

The frame is mild steel and not a hardened alloy so it doesn't anneal. You can weld on it and heat it all you want. Some car bodies are hardened alloy but not the 80 series.



Don't confuse temperature and heat. An OA torch will raise the temperature of the bolt rapidly while the threaded hole in the frame remains relatively cool. Steel shrinks when you raise the temperature above the A1 phase transition temperature (about 1,400 F) and then let it cool. The shrinking makes it come out easy. Heating with a propane torch for 2 minutes puts more heat into the frame than 15 seconds with an OA torch.

Annealing has nothing to do with hardened alloys. It's a process of relieving stress using heat to rearrange the microstructure present in all metals. Or at least it was when I went to school. Rolled sheet steel, such as that used in the 80 series frame, has inherent stress in it due to the bending operations. These stresses impart a great structural strength to the section than would normally exist. Heating the rolled section beyond 600°F will anneal the frame and weaken it.