I have a few extras of the original knobs (complete with insert and set screws) for the control panel on the Universal I and III power carriage presses. If you are missing a knob or have a damaged one let me know. I could sell them, but would prefer to trade for any of these parts I need for my Universal IIIs:
Auto Frisket tower spring X-3550
Washup Tray X-17380
Sheet Side Guide B-26
Metal Feedboard Edge
Vibrator Crescent M-184
Adjustable Bed Scale X-6637
Adjustable Bed Scale X-6638
Cycle Start Button
Roller Dust Cover Retaining Magnet
Gripper Lever Elbow

And just so you know, these are standard General Radio knobs available as new old stock from some of the finer folks selling American tube radio parts.

Daniel Morris
The Arm Letterpress
Brooklyn, NY