Removing steel screw from brass

[bluedog225]

there’s always one. This is the group head from the little espresso machine I’m trying to repair. I managed to get all the other screws out with my favorite solution of automatic transmission, fluid and acetone. This one is blind and stuck.

I know if I try and drill this out, I’ll make a mess of it. I’d like to dissolve it out. The candidates are alum, battery acid, and Clorox. All warmed and outside.

As far as I can tell, the alum will be the safest for the brass and generally fine to work with. But I’d like to hear from anybody who has experience doing this.

Thanks

 

[PCustoms]

I would NOT use chemicals as that part appears to be plated.

Drilling is really the correct option IMHO

 

[bluedog225]

I don’t think it’s plated. Just cast and milled. Could be wrong.

 

[larry_g]

Don't abandon the idea of drilling and tapping a new hole just adjacent to the existing one if the mating part can be drilled in the new place also.

 

[The Cobbler]

did you try to heat around the screw ?
I also agree with relocating the screw.

 

[Jim greengo]

Easy out,left handed drill bit?

 

[bluedog225]

Tried the alum. Supersaturation. Boiled for several hours. Left overnight wrapped in blanket.

A hot plate would have have been ideal. No got.

Good progress. About done.

 

[bluedog225]

 

[kerrynzl]

did you try to heat around the screw ?

Brass has a higher coefficient of thermal expansion than steel.
So heating is the way to go.

It also contracts more when cold, I have successfully removed press-in brass bushes by putting the whole component in the freezer so the brass shrinks more than the steel

 

[Beerhippie]

I've heard of the alum trick for removing broken/seized ferrous fasteners from non-ferrous metals, but this is the first example I've seen. Very impressive!

That's going in my bag o' tricks!