IBM Model F107 - New Foam

[hammelgammler]

Hey ho,

I'm currently in the process of restoring my F107, and as for now I changed the layout to ANSI, but after I put everything back together, I realized that the barrels in the middle row (where the return key is) have a huge amount of wiggle to them.
The ones in the first rows are fine though.

So after I put it together, I threw a stabilizer in for the return key, and when pressing return on the left side, under the stabilizer, the key doesn't click, only when I press it really far down. It's just not right.
I really don't know if that's because of the kind of huge amount of wiggle the barrels have, or maybe because of something else. The second F107 has some amount of wiggle too in the middle row, but my F122 doesn't have any wiggle at all.

Maybe I need a new foam for them? And if I do, where can I get some in Germany? The threads I saw were only for the US market, but do I really have to import some kind of foam from America? There has to be something similar in Germany.

If any of you have a clue where the problem is, please let me know.

Best regards,
David

[snoopy]

I used 'Moosgummi' on both of my F62. Worked very well and feels good.

[tigpha]

Hi hammelgammler, I have reasonably good results with 2mm neoprene foam.

I have noticed that Model F front and back plates have a tendency to separate down the centre, when they are pressed together at the edges by the fixing hooks. The result is similar to what you describe. I tried to replace the foam with 3mm polyethylene foam, and that was too stiff, I may have slightly bent the plates apart.

I think it may be caused by the perforations in the front plate, for the barrels to pass through, making the front plate slightly less stiff than the back. I may try to tighten up the fit by increasing the curvature of the front plate, but I'm not rushing into that experiment. I will first find out if I am able to get a replacement plate laser-cut and folded before risking destruction...

[fohat]

Very shortly I will be posting an abbreviated build log for my F-107, but attached are a couple that might help.

Except for the XT, and possibly the AT, I have come to believe that the Model Fs suffer from variations in curvature between the inner plates after being taken apart and put back together. Obviously, the thicker and stiffer the foam, the greater the problem.

I have concluded that in just about any Model F reconditioning job, a small number of bolts somewhere near the centerline of curvature is a huge help. They really tighten the whole thing up considerably. Obviously, be cautious to avoid traces when you drill your holes!

See the attached photos of my 3 bolt locations. One near the bottom left of Tab, one at the right end of Right Shift, and one near the bottom right of Page Down. On the shot of the plate, you can see the holes, and you can see the screw heads poking out on the one with the keys installed.

[seebart]

Hmm very interesting fohat. I have only ever dis- and reassembled one Model F being a 3104 Terminal board but I had some problems with the plates when lining them up for reassembly. It worked out in the end but I had to use force and slightly bend two of the hinges which really bothered me at the time. Of course I did not drill at all. Anyway yours looks like a phenomenal job.

http://deskthority.net/keyboards-f2/ibm ... hilit=3104

[fohat]

Hmm very interesting fohat. I have only ever dis- and reassembled one Model F being a 3104 Terminal board but I had some problems with the plates when lining them up for reassembly. It worked out in the end but I had to use force and slightly bend two of the hinges which really bothered me at the time. Of course I did not drill at all. Anyway yours looks like a phenomenal job.

Thanks. I will put together some photos. I desperately wanted to do a "true" metal case and so I took it to a metal shop for shot blasting to get a matte textured finish. I did not want to polish it shiny and have to maintain that perfection long-term.

The guys at the shop could not get an even texture and consistent color, because, according to them, it is not really a good aluminum but rather a "very soft" alloy that would always leave a blotchy and uneven finish. Whatever.

Rustoleum has some really nice metallic paints these days, so I did the front inner plate in "hammered copper" and the outer case in "oil rubbed bronze"

I wanted something closer to IBM's "industrial" but that "oil rubbed bronze", although dark, is exquisite.

[hammelgammler]

Wow fohat, you did a really great job with that F107!
Thank you very much for you pictures. I think I will try a 2mm "Moosgummi"-Foam first, and see if the problem is gone.
But the bolt-mod is a great idea, I think this is even better with it. But I don't really have the tools for that...

[Hypersphere]

@fohat: Did you consider powder coating the case? Would this work better than paint on the soft cast aluminum?

[fohat]

After spending $65 on the shot blasting I just didn't want to pay something on that same order yet again, even though there was a powder coating shop just a couple of hundred yards (meters) away from the metal shop.

This is already by far the most expensive keyboard that I have owned, and I am about worn out.

Also, to be honest, I have not been overly impressed with the powder coated photos that I have seen.

I know all about powder coating, and we sell some powder coated products at my company, but most of them are glossy and that is absolutely not what I want for my keyboard.

[fohat]

double post, sorry

[fohat]

But the bolt-mod is a great idea, I think this is even better with it. But I don't really have the tools for that...

I have a hand-held drill (decades-old, heavy, with a cord) and all you need is a fresh sharp bit. If it is a "wood/plastic/metal" bit from the hardware store it will wear out rather quickly, but drilling 3 holes should be no problem. I believe that I used M3x12 machine screws and nuts.

I put the PCB on the back plate and drill from the PCB side where there are no traces. Afterwards, I attach front plate and drill back in the other direction.