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geekhack Projects => Making Stuff Together! => Topic started by: bmmcwhirt on Sun, 03 December 2017, 05:57:21

Title: IBM Model M SSK Boltmod issue, need advice.
Post by: bmmcwhirt on Sun, 03 December 2017, 05:57:21
I did a boltmod on one of the SSK I have. Everything went fine but after putting things back together there are two places where the keys now are too close. switching around the key bases made little difference, but I want to know if this is a common issue that the tolerances were that far off? Do I just need to swap them around till I find a combination that works or did I do something wrong?

Thanks in advance.
Title: Re: IBM Model M SSK Boltmod issue, need advice.
Post by: E TwentyNine on Sun, 03 December 2017, 08:08:52
Bolt modding does nothing to the layout of the barrel plate, just snugs it down better to the backplate.  Your keys should be exactly where they were.

Which keys and how bad?
Title: Re: IBM Model M SSK Boltmod issue, need advice.
Post by: fohat.digs on Sun, 03 December 2017, 09:22:09
"Too close" to what?

If the internal assembly is shifted off-center a bit, perimeter keys can rub against the case opening. The internal assembly can be jiggled a bit as you put them back into the case.

And if key caps are rubbing against each other, the bottom edges of the skirts can be lightly sanded.


Title: Re: IBM Model M SSK Boltmod issue, need advice.
Post by: bmmcwhirt on Thu, 07 December 2017, 09:19:43
There are keys that touch each other. The M/N is the worst as often pressing one presses moth keys down, that's how bad it is.

Title: Re: IBM Model M SSK Boltmod issue, need advice.
Post by: E TwentyNine on Thu, 07 December 2017, 09:28:34
There's no instance where that should happen.  Have you tightened down the bolts unevenly, causing the barrel plate to warp?  Make back off a bolt or two and watch how the keys move?

Beyond that, fohat's idea to trim the bottoms slightly is the simplest approach.
Title: Re: IBM Model M SSK Boltmod issue, need advice.
Post by: bmmcwhirt on Thu, 07 December 2017, 10:22:56
Two things, I think there are some lax tolerances there. The big problem was the metal plate had a slight bow. It wasn't visible and unless you put it on a table arc up and look closely at the edges you would never know. It was just slightly enough to make that difference. Between straightening the bow and swapping keys then getting a different M cap things seem to be just fine.