KG wrote in
:

Another suggestion is to mount 2 drills in a lathe, place the center
punched pin between them and slowly turn it. One or both drills will
intermittently grab and give you a hole that you may use an easy out
in to allow you to drill out the other end. Please let us know what
works.


The double cutter approach seems to be the favorite. I had originally
been thinking of doing this in a mill, but upon further reflection, I
agree that a lathe is easier. I don't have to make a fixture for the
cutter on the "bottom" end, I can just put it in a collet. I also have
full visibility on both ends to see how things are progressing.

With all this in mind, I took a few measurements. The pin is smaller
than I thought, it's 6 mm in diameter. The dimple is too shallow to
allow using even a 90 degree countersink, so I'm left with drill bits or
end mills. I think a pair of 1/4" ball end mills might work, but
something smaller would be better. The swaging isn't perfectly
centered, and I want a little margin so I don't end up cutting into the
link. I only need to get the swaged part thin enough that I can easily
press out the pin without distorting the link.

A pair of 13/64" ball end mills should do it. That works out to 0.203",
compared to 0.236" for 6 mm.

Time to go shopping.

Doug White