Atari ST connectors (was: Atari SIO bus connectors found)

[Tony Duell]

> I've come to the conclusion that most people who have success with 
> tap extractors buy really cheap taps that break if you look at them 
> crosseyed.  A good tap, when it breaks is impossible to remove with a 
> tap extractor.

Good tapes are, of course, hard and thus brittle.

Most of the time tape break for one of 4 reasons : 

1) Applying a sideways force (not just a torque) to the tap. Often by 
using a ppoor tap wrench

2) Not clearing ou the swarf often enough. The old rule was '1 turn 
forwards, them half a turn back (to clear the swarf)' With practice you 
can feel when it's gettign too stiff, I normally remove the tap 
completely every few turns (peaticularly on blind holes) to clear the 
hole out/

3) Using a blunt tap

4) Haivng too small a hole to tap.

I suspect a tap extractor would work for case (1), but the sort of person 
to have a tap extractor is also the sort of person to use the right tap 
wrench and apply an even torque to it.

> 
> A very slick way to remove a steel bolt or tap that's sheared off in 
> an aluminum casting (e.g.  a hard disk body) is to use nitric acid 
> and a little heat--the acid doesn't bother the aluminum but eats 
> enough of the steel to loosen it for removal.  I've heard that alum 
> (I don't know what sort, probably amonium) also works.

I've heard EDM can work for this, but I've never tried it. The though of 
discharing large capacitors charged to 50V or so is a little 'interesting'

-tony