Modifications:IBM Model M:Nut and Bolt Mod
This articles covers the so-called "nut and bolt mod" or "bolt mod" for the IBM Model M keyboard. It entails replacing the plastic rivets that hold the keyboard mechanism together with machine screws and nuts. You will need
- Flat head screw driver
- Small Philips screw driver
- 4mm socket
- 5.5mm or 7/32" nut driver
- Sharp chisel
- Drill press, hand drill, or Dremel
- 1/16" (#52 or metric 16) drill bit
- M2.0 x .40 tap (optional)
- 87 x M2 Screw, 8mm Length, .4mm Pitch (McMaster Carr 92005A029)
- 87 x M2 Nut, .4mm Pitch (McMaster Carr 90592A004)
- 87 x M2 Washer (McMaster Carr 93475A196)
If the end goal is just to replace some broken rivets, it is possible to do this without completely disassembling the board. There are some risks that, should they occur, will require full disassembly to rectify. It is important to keep the barrel frame snug against the back plate at all times. Use a small clamp if you have to. If you let the two separate, the hammers will fall out of their rockers (especially if the key caps are still in place).
Also note that once some rivets start to break, more usually follow.
Follow the steps below until step N. You can use the chisel to even-out any broken rivets that are sticking up, but don't slice rivets that appear fine. Use your fingernail to check the integrity of seemingly in-tact rivets and prepare those as well. Then proceed to step M.