Shortening a Model F space bar

AndyJ

04 Jan 2023, 20:35

Does anyone have any suggestions for shortening the space bar on an IBM Model F?

Given the front is smooth and the top is textured, the glue joint is probably going to be visible. I can live with that.

My "A" plan is to make a glue jig out of some Shapelock plastic; spray the space bar with non-stick cooking spray, press the Shapelock around it, and let it cool. Then use the modeler's saw I use for balsa wood to cut the space bar. It has very fine teeth and is very narrow, and should make a clean cut. Use the Shapelog jig to hold everything in alignment when I stick the pieces back together.

Cyanoacrylate super glue, or solvent glue? What kind of plastic is the IBM space bar?

Or is there a simpler way?

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fohat
Elder Messenger

05 Jan 2023, 01:46

Which Model F? The 122-key already has a Model M sized space bar, and can easily be adapted for the different wire.

If you are doing an ANSI-mod + Alts to an F AT, then you can also do a mod to use an M space bar while keeping the black "undercarriage" piece.

My guess is that adapting an M space bar could be easier and more durable than chopping down an F bar. Note that if you cut it you will probably have to address the stabilizer wire and tab issue anyway.

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digital_matthew

05 Jan 2023, 16:38

Just in case fohat's suggestions don't work for you, Model F spacebars are almost always made of PBT. XMIT made a post about gluing PBT caps here:

viewtopic.php?t=17135

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Muirium
µ

05 Jan 2023, 17:34

Meanwhile, if the mysterious F in question is an XT, then the only viable route involves changing that one variable…

AndyJ

08 Jan 2023, 09:46

PBT - thanks!

It's an F/AT. I have a Code key and spacebar from a typewriter, but together they're a bit longer than the space bar on the F/AT. I thought I would have to shorten the spacebar or trim the bezel, but the typewriter spacebar barrel is in an entirely different location. The M spacebar is shorter than the typewriter space bar and it will fit in the slot with the Code key, but that requires shifting the spacebar all the way to the right, so the barrel won't line up at all. The Code key lines up with the barrel for the alt key; it would need another barrel added to guide it.

I thought the Code key would be better than an M alt key to use as a backspace key, but it's looking like the smaller alt key might not really be a problem.

I decided not to go to Colemak after all, but I thought the left hand backspace was a fine idea. But I like the Control key on the center row; I'm used to it there. It turns out the left edge of the space bar is actually easier for me to hit with my thumb than the Control key with my little finger.

85mm F/AT space bar
138mm typewriter space bar
132mm M space bar

1.5u M alt key
1u F/AT backspace key
2u M backspace key
3u typewriter Code key

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