What steel to use for expander?

[Lance Boyle]

Yep bare concrete, 5” with rebar. It didn’t flex much.

I will see if I can grab some scrap belt. I actually have to talk to the quarry guys for some gravel.

Even more good wisdom.

[country gent]

You will need a special set of mics to measure threads , some what expensive and a pain to set up and use as they are only good for a certain range of pitches. Mitoyo made a set o-1 with interchangeable anvils. You can use thread wires 3 wires of a set dia and a chart with the constant to convert. Wire sets are cheaper but require some math and coordination to use. holding three wires 2 in bottom threads 1 in top of threads takes some practice. Unless truly needed we used wires and measured the matching part or existing part. Made the new thread the same.

We did a lot sitting on a tall stool. Not really sitting but a sort of propped up standing. Feet were on the floor and butt was on the stool sort of leaning against it . Mills Shapers grinders we sat and ran them. ( One young Female apprentice had a box to stand on so she could reach the bridgeports head and on the big lathes see over the tool post). The last shop I worked in had wood block floors and were much easier to stand on. We used metal belting in one shop rubber mats are comfortable but can snag feet up when lifting or moving.

[Lance Boyle]

I know that test fitting in something, like in a stock nut, is a hack and liable to be off spec, like it was.

I had my machinist friend demonstrate the thread measuring wires in his shop. I have not picked up a set yet.

I burned myself there, I backed away the compound and the live center and was test fitting the die body. I completely over looked the little lock ring that ended up not fitting.

Learning curve!

My set up was good practice for setting up barrels when I get appropriate experience. I used the four jaw chuck, the live center, and used the spider screws on the spindle’s left. Dialed in all three to indicating less than a thousandth. My gunsmith friend, where I used to live, taught me how he set up through the headstock with a four jaw for barrel work on his old Sheldon.

My feet and back are mostly better today but I need a pad for sure.

Ps the box step isn’t a bad idea. The grizzly lathe stand on my leveling feet is a touch tall to see around the tool post. I am only 5’3”.


ETA on the plus side I am happy to not be able to see any runout when threading the expander into the die, straight and no excessive slop. My factory expander stems have enough slop to wobble and can be locked off center if you don’t set up with due care.