IBM Model M2 Bolt Mod

[hvontres]

I had an old Model M2 with busted Caps in the Garage that I ended up getting for free off E-bay a while back. After I inherited a full 1986 Vintage Model M, I wanted to try to fix it up to take to work. Unfortunately after I managed to fix the Caps, I also found some membrane damage and in the process of trying to fix that, I ended up pretty much bricking the membranes. But now I am embarking on what I am refering to as project MF-2 which in theory will convert this to some kind of capacitive setup....

My first mod involves making the board more serviceable by replacing the plastic clips with brass inserts and using button head screws coming in form the bottom.

The first step involves melting the inserts into the clip pockets. This is fairly simple. I just used a 600F soldering iron and slowly melted them into the plastic. The inserts I ended up using are about 4.6mm in diameter. A slightly bigger insert would probably be better
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After the insert were in, I broke off the clips and then used a 3.2mm (1/8") endmill to put a hole in the lower part of the case at each clip location. I probably should have used a 4mm, but I didn't have one on hand. I ended up centering the endmill over the edge of the stub of the clip. This pretty much puts you on center with the square pocket in the top part.
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I am not sure a drill would work for this operation, since the remaining part of the clip and the little rectangular cutout from the mold will probably make the drill walk too much. This makes this a bit of an advanced operation.

After that, I just screwed the two halves together using some 8mm long button head screws. I used those to get the full diameter head with a low profile to minimize interference.
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Unfortunately, one of the screw holes ends up going right through the center of the label.

There is still a fair bit of flex in the case, probably similar to a generic OEM rubber dome. However, there is no appreciable squeak.

I hope this helps somebody out there out with yet another project they didn't think they needed 

[funkmon]

You may be the only person in the world who has bolt modded a Model M2. That's awesome man! I hope the keyboard works!

[hvontres]

I'm sure at one point there was only one bolt moded model M as well 

Unfortunately, the bolt mod was the easy part.... now I need to figure out a way to repair/replace my mangled membrane. I tried some simple experiments with a capacitive sensor today, but so far no luck yet... I guess I'll need something a little more sophisticated than clear plastic and copper tape.

[fohat.digs]

When restoring obsolete workhorses, buying 2 (or more) to get the parts to build one is often the best plan.

[hvontres]

I'm not sure trying to get a second M2 is worth it at this point. After all, the original ended up being free after I got a refund due to the bad controller. There is one up on Fleabay for $60 right now, but it sounds like the membrane is also bad on that one. After some searching this afternoon, it looks like a Logitech Deluxe 250 might be a good membrane donor. I'll know in a couple of days. And as an added bonus, it would give me a usb controller as well.  Too bad all of the crappy HP/Dell keyboards moved the F keys closer. I have a couple I wouldn't mind sacrificing...