[topgun]

A couple of points:
1) Why not machine it out of 1018 steel? Tormach can handle steel.
2) Why do you want to push the pin out? I made one for my team and it's set to push the pin out enough so you can break the chain while leaving the pin in. Then you have a pin ready to push right back in. This is much more secure than any connecting link you would use.
3) I used an injector pin for the part that is actually pushing against the chain pin. These are very hard and won't mushroom out, plus you can get them sized to fit thru the pin hole.
4) Make sure you have enough leverage available on the handle to actually move the pin. We used a shcs so we can put a long allen wrench in it or even use a drill with a hex bit.