Model M: Bolt Mod vs. Screw Mod?

[Kavik]

I see a lot more posts about bolt modding Model Ms than screw modding them. I'm not sure if one method is just more publicized than the other or if one is inherently better.

What is your opinion on the two methods? Can I perform one method and then switch to the other if I don't like it? It seems possible to go to a bolt mod if I don't like a screw mod, but maybe not the other way around.... There doesn't seem to be nearly as much info out there on the screw mod method, but it looks simpler, less time consuming, and less tedious (no small washers and nuts).

I am typing this on a 1989 Model M that I bolt modded, so I do have some experience with that method (and enough parts left over for another). It only had a few broken rivets and didn't really need it, but it didn't feel as good as my other non-modded '89 M. After bolt modding it and adjusting the tightness of the bolts, it feels better, but I still don't know if I really like the feel as much as my non-modded M. I'm not sure if that's just because of the particular board or the method I used to fix it (I've heard each Model M has its own feel).

ANYWAY, I have a 1995 Lexmark Model M that I ordered from Unicomp last November. It was "new" old stock, but something like 50 rivets were broken (might have been because they did a really bad job packing it). I bought it purely because I thought the rivets would be 100% intact.... So it's been sitting against the wall in my computer room for months while I decide what to do with it - another bolt mod or a screw mod. My brother expressed an interest in having it, so now I finally have a reason to go through with fixing it.

Suggestions, advice, comments on the pros/cons of each method? Have any of you had experience with both?

[fohat.digs]

I have always done a complete tear-down and thoroughly cleaned every single part, then used the nut and bolt (actually they are M2 machine screws, of course) style mod.

If you are certain that the internals are clean, then maybe you leave the layers sandwiched intact and simply screw through one side. I always felt that the nuts gave me better control, but it would be a lot faster to just run screws in.

With a 1/16" drill bit and M2 screws, the holes are perfectly undersized for the threads to cut their way in.

[rowdy]

In most cases I'll just wash the case and give the internals a good brush down, if there aren't too many broken rivets.

My current project is bolt-modding and ANSI-modding a Model M 122.  Getting the bolts to fit was a horrendous experience.  Perhaps it gets better with practice, but I was seriously considering switching to a screw mod at several points.  This one I did need to completely disassemble in order to undertake the ANSI mod.

I have 5 Model M keyboards in all, 2 101 key, 2 SSK and 1 M122, and they all feel different.  The best by far is an original condition 101 key Model M - it has one missing rivet and feels fantastic across the board.  The worst is probably the older SSK which feels very gritty and somewhat inconsistent across the board, plus a couple of modifier keys stick a bit.

I've seen a video from Phosphorglow who did a screw mod.  He also put a sheet of coloured vinyl over the top of tbe barrel plate, and the screw mod may have been to help the vinyl sheet to lay flatter (no bolt heads sticking up).

[invariance]

Can I perform one method and then switch to the other if I don't like it?
It seems possible to go to a bolt mod if I don't like a screw mod, but maybe not the other way around....

As you say, you can go screw mod and if you don't like it, change to bolt mod.
Going from bolt to screw mod cannot be done because the screw mod relies on the posts being drilled undersized and the machine screw 'cutting' a thread into it.

I'm in the rooky league here as I have only performed one machine screw mod and no bolt mod, unlike fohat and rowdy - Hi guys, me again 

Part of the benefit of a machine screw mod is there aren't screw heads messing up the top of the barrel plate - great for ocd.  If you decide to try screw mod first, the procedure requires the screws to be inserted from underneath and when using your excess parts, the threads will be protruding through the top which will negate the 'clean look' benefit.  So, ideally you will need to purchase shorter screws.

The second consideration: bolt modding around the numbpad + and enter if required can be awkward as the screw fowls on the stabiliser.  There is no problem with a machine screw mod.  A workaround would be to screw mod at these problem points, even cutting down the oversized screws.

So, with the above considerations, if you decide to try the machine screw method first, source some M2 x 6mm (converting to about 5/64 x 15/64) and see what you think.

[3K]

Related question: When modding a board with nuts and bolts, what length do you choose for the bolts/screws?
I went with 8mm / 0,314961" and had big trouble putting on the nuts. (I stuck with a tutorial, which said 8mm are fine)

Now I ordered 10mm and 12mm screws, to test out what fits best.

[rowdy]

Related question: When modding a board with nuts and bolts, what length do you choose for the bolts/screws?
I went with 8mm / 0,314961" and had big trouble putting on the nuts. (I stuck with a tutorial, which said 8mm are fine)

Now I ordered 10mm and 12mm screws, to test out what fits best.

I've used M2x8mm bolts, and had an absolute bugger of a time getting quite a few of the nuts on.

The trouble is there is almost no space under the plate when it is fitted into the case, in fact there are little square cutouts in the bottom half of the case for just the plastic rivets to fit into.

So anything sticking out much further than an 8mm bolt is going to foul the case.

I've already encountered that where the front (space bar) edge of my plate won't go back in the case as the plastic is thinner so the bolts stick through much more.

[Kavik]

I ended up doing a partial bolt-mod today because my brother was coming over, and I just wanted to get it done and give it to him. I think I'll try a screw mod if I ever get another Model M that is missing rivets.

I only did a partial bolt-mod because most of the rivets around the alpha keys were still intact and not brittle enough to come off without deliberate force. This actually made the process quite a bit easier because I just drilled holes with the metal plate in place (without taking the sandwich apart). This allowed me to get a really good angle on all the holes and get the holes pretty close to center; I learnt from my last experience that center on the plastic doesn't necessarily mean it lines up with the plate's holes. I did have a problem with the drill bit walking on two of them because the rivet hadn't broken off evenly. I was able to smooth these over with the dremel ball end bit, but I'd already made a double hole on one of them by the time I thought of doing that (luckily I didn't mess up the membrane).

One disadvantage of not taking the sandwich apart is that, if any of the flippers get out of their grooves, it's harder to fix them. The numpad's 5 key got its flipper crooked, wouldn't click, and usually didn't register a key press. I had to undo the nuts I'd fastened there and use a flathead screw driver as a wedge between the plastic and metal plates while I straightened the flipper through the barrel.

Overall, I'd say the key feel isn't great, but I think that has more to do with the fact that it's a 1995 Lexmark board (Who knows? Maybe it would feel better if I just bolted the whole thing instead). My brother isn't a keyboard enthusiast, so I don't think he'll notice the difference; he just wanted a vintage keyboard for his new PC build I helped him with.

Related question: When modding a board with nuts and bolts, what length do you choose for the bolts/screws?
I went with 8mm / 0,314961" and had big trouble putting on the nuts. (I stuck with a tutorial, which said 8mm are fine)

Now I ordered 10mm and 12mm screws, to test out what fits best.

https://www.amazon.com/gp/product/B009OJZD0U/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B000NBGG36/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B000NHXO1M/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1


These are the exact items I ordered. As long as you get the holes drilled at the correct angles, they are long enough. Some people say you don't need the washers, but I think they help since the nuts sometimes go through the plate if the hole is too big or off center. They also give the job a more finished look.

EDIT: I forgot to say that another advantage of partial modding is that you get to leave the very bottom rivets in place, which you can't bolt because of the lip at the bottom of the barrel plate.

[fohat.digs]

There is no perfect answer. What I settled on for the last few that I have done was a hybrid affair.

For the very bottom (below the space bar) row I use M2x8mm screws coming up from the metal plate with washers but without nuts, since they would interfere with the ribs on the barrel plate (which can be trimmed easily, of course, if you want to fit nuts). Using a 1/16" drill bit is perfect for a slightly undersized 2mm hole.

For the next couple of rows I use 8mm screws with nuts (and washers if I can get them on), and for the remaining upper rows I ordered a bag of 9mm which makes the installation of washers easier.

If your holes are not drilled nicely plumb it is hard to get the screws through from the front if they hit metal rather than air. If you are not drastically off, you can usually back the screw out, then screw it back in with serious pressure on both sides to force it to find its way into and through the hole.

[dorkvader]

https://geekhack.org/index.php?topic=62226.0

I normally don't use washers anywhere because it always felt like a waste of time: the keyboard felt the same with and without and putting it together is much more annoying, so I omit them usually. On the very front row, originally the guide posted by ripster recommended driving in bolts with washers the opposite way. Nowadays I also omit this because it makes little difference on feel and makes assembly and fitment harder.

When you're putting it togethere use a frame like fohat recommends, or you can be lazy like me and use the case pieces to support everything. insert the flippies, put the plate on and get a few nuts on the middle, but keep them loose. then go around the keyboard adding nuts. FInally go through them and tighten down. just until you feel a tiny bit of resistence. repeat the process several times. I cannot stress enough how little torque is required here. Especially with older barrel frames you can easily crack them and a bolt mod will get better (and more even) pressure than the rivets had anyway.

[masilver]

I have run into problems with the typical bolt mod.  There is limited room between the plate and the bottom plastic of the keyboard and often the bolts and washers will cause the keyboard to have dead spots since they are too large too fit properly.

I've ordered waffle head M2x8 screws, which have a flat top and take up less room.  I screw these in from the bottom along with a washer.  I may or may not bolt up to 10 of the screws from the top.  (The rest are just too hard to get to).

I call it a reverse partial bolt mod.  It's been very reliable, although I don't really put my keyboards through much stress.

...Michael...

[Kavik]

I have run into problems with the typical bolt mod.  There is limited room between the plate and the bottom plastic of the keyboard and often the bolts and washers will cause the keyboard to have dead spots since they are too large too fit properly.

I've ordered waffle head M2x8 screws, which have a flat top and take up less room.  I screw these in from the bottom along with a washer.  I may or may not bolt up to 10 of the screws from the top.  (The rest are just too hard to get to).

I call it a reverse partial bolt mod.  It's been very reliable, although I don't really put my keyboards through much stress.

...Michael...

By dead spots, do you mean groups of keys that don't register? The 1995 Model M I partially bolt modded has some weird issue were it hits CTRL + F and then continually searches the page (as if it were holding the enter key). My brother and I can only reproduce it on his computer (and no others). I tried loosening the bolts a bit, but it kept happening, so my brother just stopped using that board.

[masilver]

That's not the issue I was seeing.  My Ctrl and Alt keys would stop working until I'd remove the keyboard from the case.  However, I think I remember hearing of stories similar to yours.  Did you try using the keyboard outside the case?

...Michael...