Seized stainless screw into aluminium

On my steering pedestal I could't get one of the m10 bolts out of the base. After a week of cursing I had sheered the bolt head off. Couldn't get plusgas into the thread. Eventually i drilled a tiny pilot hole parallel to the bolt between the bolt thread and the base. This allowed plusgas into the threaads and the bolt came out with molegrips on the stump. I also used heat from a gas soldering iron with the flame jet nozzle fitted. Seemed to help get fluid in after repeated heating/cooling.
 
Boiling water onto the ali not the SS

The Ali will expand just a bit faster than the SS as they warm up.. that cracks the oxide powder.

Do not use a blow torch as it is too fierce and the head difference will be lost..

You may need a couple of dowsings

Good luck
 
Thanks for all the suggestions but it's the small (3mm?) seized Allen grub screw in the S/S insert that is the problem. My concern is what mess wil be left if I start drilling, the paint is still perfect on the shelf -- I guess a larger insert will be required...?
 
TQA said:
As G12 says heat [ the ali not the screw ] then use an impact driver initially with the correct allen key but a torx one sixe up as the next resort.

I have dismantled many an old m/c engine this way. An impact driver is your friend.
Click to expand...

But a mate who comes around with his cordless electric impact driver is better still IMHO.
Great bits of kit.

I also suggest heating with hot air gun and then applying penetrating oil.
It penetrates a bit better at 150degC.
Another trick is heat a hex drive bit in a gas flame.
Thermal shock is the name of the game.
 
GandJ said:
I have exactly the same problem -- heat has moved things before but the size and location means probable damage to the pristine paint work -- have you been successful?
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Yes I was. I used a slightly large Torx bit and a very big screwdriver so lots of grunt could be applied. I knew that possibly i was going to shear the head off and was prepared to drill it out, so i just forced the bit into the hole and gave it some wellie!
 
For a small diameter screw - no brute force. No WD40 (the only stuff I found in UK that works is 3-1). Real penetrating oil might be, haven't seen any good one though.
Proven way times past was to soak in diesel fuel and heat (carefully! ;) ). Devise some way to keep a pool of diesel (or similar) on the screw, heat all so it's warm but not in flames :D and wait. Few days...
Then, if it's still not turning, pour boiling water on it and try again immediately.
 
Apply as much torque with your Allen key as you think safe and hold, rapidly and continuously tap the Allen key as if trying to drive the key further into the hex whilst an assistant pours boiling water over the fixing if it's small or applies dry heat if larger.
 
boguing said:
Ammonia - or whatever it's called in liquid form - is alleged to break down the Alu Ox.

Easyouts are great, but once you have broken one you are in a whole world of trouble.

I'd leave it soaking in Ammonia, then hit it with a hammer and drift to make sure the chemical bond is broken, finally using the Allen key again.
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You can use a solution of Alum to dissolve ferrous items stuck in non-ferrous ones, a great fix for broken taps in castings so could work if you can get something like a blueTak/plasticine/putty dam built around the screw and fill that; see http://www.tap-die.com/contents/en-uk/d296_Tip_Remove_Broken_Tap_Drill_Reamer_Tap_and_Die_Co.html and http://www.homemodelenginemachinist.com/f25/dissolving-broken-tap-aluminum-brass-233/

Also agree that ACF50 is good stuff
 
A cordless drill with an adjustable torque clutch makes a good delicate impact driver. Alternating forward and backwards at a high clutch setting (not locked) has worked a treat in the past.
 
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