From Wayne's Dusty Box of Words
- Cap Iron screw: 5/16-18 BSW
- Frog screws: #12-20
- Tote & Knob bolts: #12-20
- Tote Toe screw: #12-20
- Frog Adjusting Plate screw: #12-24
- Frog Adjusting screw: 1/4-24 American/Unified;
- Brass Adjusting nut: 9/32-24 American/Unified (left-hand thread);
- Lever Cap screw: 9/32-24 American/Unified.
- Much of the rest on planes is also #12-20
If you do a lot of restoration, it's probably worth your while to track down a tap & die in #12-20. It's pretty rare, but you do come across them occasionally.