I don't get out to the tools often lately. A few months being banned from cutting tools because of some health concerns (and a few more yet to go before I'll be allowed) forced me to do this one with a little more surreptitiousness (just being sneaky with my tools).
I picked up a beam compass from my wife's uncle (none of his kids wanted it). It was missing a few parts, like the beam, so I ordered some 3/16" hex bar that fit, and sliced it where that bar was bent. I've had this in this state for a year or so, and had an inkling to create some extension tubes to be able to break this down into the smaller size, as well as merge the bars together.
I started with a 3/16" hex broach in 3/8" stainless tubes, first on the 3-ton arbor press, and then realizing that this wouldn't have the capacity to push it through the tube, switched to aluminum tubes and even moved to the 20-ton hydraulic after the 3-ton arbor failed to push the broach through.
When that broach was flexing in both presses, I gave up, and switched gears. Since I had a 3/16" pilot hole for the broach, I opted to cut interrupted threads in the hex bar (#12-24 was the right measurement for the peaks) on one end, and turned the other end round to 3/16" for a slip fit.
I still need to tap some set screw holes for both of these stainless extensions, and I might have to make some of the thumb screws (#5-44 seems standard on my old compasses, including this one, I might as well make it match - but I can't find them anywhere for purchase). And my wife caught me because I didn't get the cutting oil washed off my hands completely enough. (Trouble!) It sure felt good to get out there, as wobbly as I am. It does look like the theory is plausible, so I'm happy.
