I machined the "milled" jackcup today. Fender used these up until end of 1952 I believe. Maybe even into early 53'.
This is not a copy of an actual cup, but a close facsimile. (as close as my eyes can see!) What the heck!... it only holds the jack...right?
I made it out of 303 stainless. One of the easiest machining grades!
I started with a 2" length...
The diameter was 1.2" so I had to turn it down to 1" dia. ( I could have started with 1" , but I didn't have any in-house...and I'm cheap!)
I held it in a three jaw chuck to turn one end so it would fit into a 1" collet.
The reason I don't finish the part in the 3 jawed chuck is because of the knurling operation. A LOT of side load is applied in that operation and it might not be secure in the chuck!
after the 1" dia is turned I place it in a 1" collet and turn the other side to 1" also. I then center drill the blank...
It's now ready to for the 3/8 drill.