Hi and Welcome to the forum!

Please post a picture and there will be many of us here than can tell you what you've got. You can also post the eBay item number and we may be able to find it there.

Mark

There was a period when the Rogers USA swivos had no stamps. Can't recall the dates. I noticed that the swivo arm currently on Ringo's OBP set in the Grammy museum had no stamp. But a photo would help.

Sounds like a later model, made from approx 1970-on. Came in around the time of the cast collet noses, and that's when they dropped the Pat Pend legend on those as well.

That's not a rivet holding the parts together, it's called a 'split pin' and is pressed in. It can also be driven out to disassemble the unit.

Thank you for weighing in, here are some photos.

That's a Rogers arm. And as stated, it has a split pin holding the piece together. If you drive out the split pin, you can unscrew the two pieces for repair or cleaning.

You also only need 2 locking screws on the holder. I can see 3, and suspect there are 4 there. The 4 hole idea was to allow positioning of the 2 necessary screws to be able to get to any 2 holes when setup. They push the internal ball against the housing to hold the top arm in place. This provides a lot of surface area for friction to keep it tight. Using all 4 holes with screws only provides 4 small ends of the screws to hold the arm in place. Much less surface in contact with the ball, resulting in overtightening, and tears up the ball.

If you have an issue with holding the arm in position, drive out the split pin, unscrew the base and check the condition of the ball.

Exact-a-mundo to the above...

Thank you kindly for your knowledge! This forum is fantastic. Is there anyone out there making the collet for Swivomatic hardware?