So I finally got some time and made a new vertical shaft. Dan had a good hack to fix it if the nut on the bottom of the shaft pulls out. But if someone wants to retain the spring action, as it was original, here’s what I did (I doubt anyone on the forum is going to make one of these for themselves, but someone may choose to hire it done at a local shop.)
The slot isn’t pictured in the original one, but it’s there, it’s against the table (photography isn’t my strong suit).
I made the replacement out of a piece of 3/4" dia. 18/8 stainless round rod, because that’s what I had on hand. Really a piece of 5/8" square stock common 1018 steel would have been easier. Stainless is a lot harder to machine.
I made the replacement bar a little bigger because I didn’t like all the original slop between the casting which rides up and down on the bar. It took several attempts to get a good fit, as I kept machining the bar smaller and smaller till it fit tight. I also had to file a small chamfer on the corners to get a good fit. The original was about .510" dia.(I say about because the original wasn’t even square). The replacement I made at .525".
I made the slot tighter too. I cut it with a 3/16" end mill. The hole in the end for the spring is a simple 3/8" hole bored all the way down and stops just short of the other end.
For the roll pin which holds the spring in place, I just used a 3/32" in pin (and hole).
If you flip it around the other end looks like this:
I had to neck down the end of the replacement bar to fit in the base casting. The neck extends .100" past the shoulder. The dia. of the neck is .508" I had to file the corners just a bit and chamfer the ends to get it to fit in the base casting, and it’s a really tight fit at that. I had to tap on it with a hammer to get it to go in the base.
The tapped hole for the screw is an M6 X 1.00. I could have used an SAE tapered machine screw, but I just decided to reuse the metric screw which came with it originally.
(Just a quick word on tapping for anyone interested. Don’t use those cheap taps sold at the hardware store, unless you are going to tap something easy like aluminum. Otherwise they are prone to break. Once you break a tap off in a hole, you are up the creek without a paddle. Broken taps are nearly impossible to get out, unless you have some special tools. Stainless is even harder to tap. I used a brand new high quality sharp tap for this hole and was still putting quite a bit of torque to tap it. I was a little worried the tap was going to break.)
Here is the part back in the tool.
The part fits real tight and won’t break loose now, unless the bottom casting breaks.