Yahnozha

Not necessarily *bad*, just different, but you have to consider the part that your trying to burn out a bushing. On a stamped piece of metal (ie: lower control arm, trailing arms etc on our cars) the metal is actually work hardened thru the metal forming process, making it a stronger piece.

Now annealing is a controlled process, but applying significant heat to an object tends to soften the metal. To what extent in an uncontrolled environment like this? Who knows. But burning out bushings on a cast steel/iron I beam on a 75' Ford Truck, I doubt your gonna affect that any.

Peter

Okay, now I'm somewhat confused. Typically, if you heat something,
like a bolt and then try to drill it, it breaks carbide bits. Same with trying
to drill something like an SS bolt.

I had also thought that the reason the bolt 'work hardens' while
attempting to drill it was because of the heat generated, and if
you go slower, using a little more lubrication, it doesn't generate
as much heat, and therefore doesn't 'work harden' as much.

From what you're saying, this is basically false. The metal should
soften up when it gets overheated. For some reason, even drilling
mild steel, it always seems to harden, or maybe it's just that the
drill bit is getting dull?

Peter

__________________
'91 SE-R track slut w/ VE
'02 G20 Sport
'95 Yamaha FZR 600 RIP
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peter.serwe@gmail.com

Peter

I am ASSuming you mean a relatively standard propane plumber's
torch. Oxy-propane generates a significant percentage of the
heat oxy-acetylene generates. The only reason I never used
propane or even MAPP torches is that I was never patient enough
to want to wait the 1/2 hour per bushing it seemed to take. I
remember trying it with a MAPP gas torch, and it didn't seem to
want to even begin to slag the rubber. Which is great for the
metal, but sucks if you want to get it done!

I know that I never had the control arms actually glowing with the
torch, the main benefit of the oxy-acetylene torch is that it's a
*highly* directed heat. With LP, or MAPP, I always found
that the gas didn't have the force behind it to really push the
soft rubber out of the way.

Peter

Yahnozha

Well drilling and flame produce two different results. Drill a bolt, say with a HSS bit, will work harden the part due to the heat AND friction, its the high friciton, high heat that work hardens the hole that you are trying to drill. Carbide should easily cut thru this unless you have a chunk of drill bit broken into the part you are trying to drill.

You also have to consider when drilling you are centralizing the heat and it cools quickly, thats another reason its work hardening, becaues its a local temper.

All and all you should always go slow and use proper lubrication

SentraDude

PITA!!!! Tomorrow I'm off to the Junk yard to pick up another LCA because I cut too deep into the outer sleeve and into the LCA, and that stupid sleeve still didnt come out!... Does anyone have any pictures or new techniques to remove that stupid steel sleeve??!

Peter

Yeah, cut them with a sawsall, 3 pieces, coerce lightly with
screwdriver/hammer, or a chisel and hammer.

Peter

SentraDude

I might have to try it that way.. I only made one cut and it didnt do squat I was able to peel the sleeve back a tiny bit but it still didnt move.. I'll try more cuts but now I'm afraid im gonna cut too deep again... That sleeve is in there solid & I dont think its rust because Im in PHX, AZ.

SENTRASER

Plenty of heat, propane torch doesn't cut it. I use an air chisel.

__________________
~Ryan
1992 NX2000 Hardtop
1989 B12 AWD wagon
1996 200SX SE-R Slowly geting the boost-treatment.
Update: the SR20 has VET+T now, and P11 forward gears

SentraDude

I would use the air chisel but ES makes it very clear not to score the metal around the busing... i guess just patience.. lol