deskthority

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Few stores in the US sell M2 screws, I order them on ebay from China. They are very cheap but plan on taking 3+ weeks to get them. If you are willing to pay considerably more, McMaster-Carr ships fast. https://www.mcmaster.com/Screws/thread- ... ad-screws/

A 1/16" bit (Imperial measure) seems perfect to me because it is slightly undersize for 2mm, so the threads can cut their way in.

dellmodelm wrote: 07 Mar 2023, 18:39 I'm in the process of getting tools together to screw mod a Model M keyboard. Right now I'm stuck on drill bit size. Can't seem to find a consensus. What's the size of the bit they use in this video?

dellmodelm wrote: 07 Mar 2023, 18:39 Also, where does one find "M2 machine screws" of the variety used by clickykeyboards.com in their mods?

It would be best to ask the author of the video to clarify this information, however, I don't think they are using Machine Screws. See this image they have on their website: https://www.clickykeyboards.com/#jp-carousel-12366 . Those are self-tapping screws, notice how thin the threads are!

In my opinion I would never use a machine screw to do a screw mod. What I mean by that is I would not drill a hole that is tight enough to rely on the threads of the machine screw to hold the barrel plate tight to the backplate. If using machine screws, always use nuts too, and drill the holes big enough so that the machine screw can enter into the holes in one linear motion without having to turn it. Yes, it's gonna be less convenient, because they won't just sit there on their own anymore, but convenience is not a good reason to kill a keyboard. Machine screws are not designed to be used as self-tapping screws, so we should never use them like that. Machine screws have thick threads, that would put a lot of radial stress on the plastic. Some nut&bolt mod guides recommend drill sizes that will result in a hole that is so small that there is mathematically no place for the displaced plastic to go (even if we ignore the bad shape of the threads on a machine screw), so the plastic probably ends up displacing in all directions, putting stress inside the barrel plate.

This is the type of problem that happens when you use machine screws, and a too small hole:

Small hairline cracks for, that grow over time, and eventually the barrel plate will start falling apart. I do NOT believe that this is because of overtightning. These radiating hairline cracks are because of the stress added to the barrel plate by a too big machine screw in a too small hole. The worst thing about them is that they can take years to show up making the bolt modder think that they did a good job, and endangering more keyboards.

Reminds me of this NSFW-ish meme: https://www.youtube.com/watch?v=5J3EElD5TuI

The only exception I can think of where machine screws would work without nuts, and smaller hole size, is if you actually spent the time to tap the holes with one of those tapping tools that actually cuts away the plastic to form threads, rather then push on the plastic to try to deform it into making threads.

Even with a self-tapping screw mod, pay attention to the drill size. The hole must be > the minor diameter of the threads. (the inner diameter). if it's not, then the plastic has nowhere to go and you're back to the same situation as above.

TLDR:

• Use self-tapping screws for a screw mod. Hole size must be > the inner diameter of the self tapping screw.
• Use machine screws for nut and bold mod. Hole size must be > the outer diameter of the machine screw, making it possible to slide the screw in linearly, easily, without screwing.
• Maybe? Use machine screws to do a screw mod with a smaller hole, but only if you tap the hole with a tool that cuts away plastic rather then just deforming it.
• Don't use machine screws as self-tapping screws!

fohat wrote: 07 Mar 2023, 22:53 Few stores in the US sell M2 screws, I order them on ebay from China. They are very cheap but plan on taking 3+ weeks to get them. If you are willing to pay considerably more, McMaster-Carr ships fast. https://www.mcmaster.com/Screws/thread- ... ad-screws/

A 1/16" bit (Imperial measure) seems perfect to me because it is slightly undersize for 2mm, so the threads can cut their way in.

Just for the record, in my opinion this is bad advice. See my other reply above. The same bad advice seems to exist on the geekhack wiki, we should try to correct it.

I always wonder how much credit is given to a keyboard with such a capital built-in design flaw.
Which by the way, as made obvious in this thread, is not as trivial as some may assert:

ArtyomTheMetroHopper wrote: 23 Dec 2022, 11:14

kbdfr wrote: 23 Dec 2022, 09:08

ArtyomTheMetroHopper wrote: 23 Dec 2022, 02:02[…] and even in a worst case scenario a bolt/screw mod just needs a power drill and some screws and your good to go.

Always funny how people say 'it's easy" when referring to something in which they are proficient, assuming it applies to everybody else.
For the vast majority of users, the "worst case" described here just means having to toss out the keyboard, because it is simply not functioning properly.
[…]

If someone has got hold of a Model M, they are most likely a keyboard enthusiast. If they are a keyboard enthusiast, they are most likely DIY inclined as a large part of the hobby centres around keyboard customisation and optimisation. Which is ESPECIALLY required for old boards.

A bolt/screw mod is just driving a screw into a circular bit of plastic, thats it. You have to try very hard to botch a mod like that.
[…]

I particularly appreciate the last line

kbdfr wrote: 08 Mar 2023, 08:06 I always wonder how much credit is given to a keyboard with such a capital built-in design flaw.
Which by the way, as made obvious in this thread, is not as trivial as some may assert:

I have said for years that the Model M's reputation for ruggedness is undeserved. One bad drop and you can have enough popped rivets to make it feel completely different in that spot. IBM went a step too far cheapening capacitive buckling spring. Nobody can convince me otherwise.

Same. The Model M is the wrong IBM board entirely. Its reputation is an accident of history. It was just where buckling spring happened to be when the modern layout was ultimately defined. Every other buckling spring was better, but Model M was there at the right time to take the glory.

?..

The proper tap drill size for M2 machine screw in plastic is 1/16" or no. 52, depending on thread pitch.

engr wrote: 10 Mar 2023, 05:40 The proper tap drill size for M2 machine screw in plastic is 1/16" or no. 52, depending on thread pitch.

Thanks, that's a very useful .pdf
But just to be very clear, that's the tap drill size, meaning, that you must use one of these tools to cut the threads if you use that drill size: I believe these tools cut away material rather than deforming material.

I don't think I've seen anyone perform a bolt mod with one of these tools. The geekhack bold mod wiki says using them is optional, and it's definitely not optional with a 1/16 hole size when using M2 machine screws.

If you plan to not use one of these tools, then you must go with something that is >= major diameter of the screw. Your .pdf recommends 2.1mm for Close fit, and 2.2mm for Standard fit.

pandrew wrote: 10 Mar 2023, 05:56 But just to be very clear, that's the tap drill size, meaning, that you must use one of these tools to cut the threads if you use that drill

The nomenclature is somewhat confusing; the tool that your picture shows is called a machine tap, but the procedure is that you first use an undersized drill bit called a tap drill, whose diameter is about 75% of the major thread diameter, and then follow it with a tap if you want to cut in the threads rather than let a screw cut them. However, if you drill into plastic, you don't have to use a tap, you can just drill a tap hole with a tap drill and then put in a screw, which will cut its own thread.

If you drill for a close fit or standard fit, the screws will not stay inside the plastic part and it will be more of a pain to assemble the whole thing together.

engr wrote: 10 Mar 2023, 06:14 However, if you drill into plastic, you don't have to use a tap, you can just drill a tap hole with a tap drill and then put in a screw, which will cut its own thread.

I very much disagree. Taps actually cut away the material, that is, they result in shavings removed from the hole after you use them. While self-tapping screws, only push on and deform the material they are screwed into. That's why self tapping screw thread profiles are thin (thread angle is small), and the threads are farther apart from each other (thread pitch is higher). It's a lot less comfortable to hold a self-tapping screw thread between your fingers (compared to machine screws), because the threads are like thin blades. This results in less material being displaced smaller distances (when compared to machine screws). Machine screws are not designed to do that, they are instead designed to support more weight. And screws in general don't cut away material.

Some very brittle plastics can't even handle self-tapping screws. For example I can't find any examples of self-tapping screws used for acrylic.

engr wrote: 10 Mar 2023, 06:14 If you drill for a close fit or standard fit, the screws will not stay inside the plastic part and it will be more of a pain to assemble the whole thing together.

Agreed that it's less convenient to use a clearance drill, cause it won't just stay in place when you haven't put the bolts on yet, however that doesn't make it any less damaging to use a tap drill sized hole without tapping the thread with one of these tools.

pandrew wrote: 10 Mar 2023, 06:35 Taps actually cut away the material, that is, they result in shavings removed from the hole after you use them. While self-tapping screws, only push on and deform the material they are screwed into.

Yes, self-tapping screws are better in that respect. My concern with them would be their compatibility with nuts because of the different thread and having a shank slot at the end.

A pilot hole, followed by a tap to form thread, followed by a machine screw would probably be an ideal solution from the standpoint of minimizing the risk of cracks, but it's also the most labor-intensive one.

engr wrote: 11 Mar 2023, 01:37 Yes, self-tapping screws are better in that respect. My concern with them would be their compatibility with nuts because of the different thread and having a shank slot at the end.

What do you mean shank slot? Do you mean like self-drilling screws like these?
I'm not talking about self-drilling screws, just self-tapping ones, like these.
Also when you use self-tapping screws you do a "screw-mod" not a "bolt-mod", so you don't end up using nuts at all. The screws go in from the bottom into the plastic and that's it.

engr wrote: 11 Mar 2023, 01:37 A pilot hole, followed by a tap to form thread, followed by a machine screw would probably be an ideal solution from the standpoint of minimizing the risk of cracks, but it's also the most labor-intensive one.

Yes. I have never seen anyone do this, probably because of how labor intensive it is. But that is the only context in which using a 1/16 hole with an M2 machine screw would be acceptable.

pandrew wrote: 11 Mar 2023, 04:00 What do you mean shank slot?

I meant these ones. Unfortunately, the terminology around fasteners has a lot of inconsistencies, with different sources using terms like self-tapping screws, thread-cutting screws, thread-forming screws, and self-drilling screws in different ways.

Also when you use self-tapping screws you do a "screw-mod" not a "bolt-mod", so you don't end up using nuts at all. The screws go in from the bottom into the plastic and that's it.

From what I gather, there are at least three different mods: a nut and bolt mod with clearance holes, a screw mod that ClickyKeyboards guy uses (with screw head on top of metal plate), and a screw mod that GH wiki describes, which calls for self-tapping screws, washers, and nuts.

engr wrote: 11 Mar 2023, 20:39 I meant these ones. Unfortunately, the terminology around fasteners has a lot of inconsistencies, with different sources using terms like self-tapping screws, thread-cutting screws, thread-forming screws, and self-drilling screws in different ways.

Oh interesting, I wasn't aware of the ones you linked. These sound like they actually cut away material to make the threads. If that is the case then these types of screws could be the safest and most convenient to use for screw-modding! I will try to source some in the future to try them out.

engr wrote: 11 Mar 2023, 20:39 From what I gather, there are at least three different mods: a nut and bolt mod with clearance holes, a screw mod that ClickyKeyboards guy uses (with screw head on top of metal plate), and a screw mod that GH wiki describes, which calls for self-tapping screws, washers, and nuts.

The GH wiki calls for machine screws, not self-tapping screws. See the actual link to the product here, and notice the shape of the threads. In the list of tools the GH wiki lists "M2.0 x .40 tap (optional)". I think i'd be okay with the GH wiki if it didn't say "optional", and instead said explicitly NOT OPTIONAL. As it is there have been multiple people who destoryed their barrel plates, because of following the GH wiki to the letter, and that is a big shame!

Anybody still have a working GH wiki account to fix this?

Muirium wrote: 08 Mar 2023, 14:20 Same. The Model M is the wrong IBM board entirely. Its reputation is an accident of history. It was just where buckling spring happened to be when the modern layout was ultimately defined. Every other buckling spring was better, but Model M was there at the right time to take the glory.

I would argue actualy having a layout that doesn't suck is a good reason to prefer an M over an F. Model Fs (Models F?) have layouts that range from ok to just plain bad. Same problem exists with beamspring keyboards imho.

daemonspudguy wrote: 13 Mar 2023, 00:29
I would argue actualy having a layout that doesn't suck is a good reason to prefer an M over an F.

I am inclined to agree. Fortunately, the 122-key terminals can be modified to something extremely close to straight-ANSI.

daemonspudguy wrote: 13 Mar 2023, 00:29

Muirium wrote: 08 Mar 2023, 14:20 Same. The Model M is the wrong IBM board entirely. Its reputation is an accident of history. It was just where buckling spring happened to be when the modern layout was ultimately defined. Every other buckling spring was better, but Model M was there at the right time to take the glory.

I would argue actualy having a layout that doesn't suck is a good reason to prefer an M over an F. Model Fs (Models F?) have layouts that range from ok to just plain bad. Same problem exists with beamspring keyboards imho.

I would rather use a board that feels good that I never have to repair than have a 100% modern ANSI layout that's inconsistent and scratchy.

F AT layout is perfectly usable for me, and the 4704 boards are really only missing dedicated f keys (which I basically only use in a preboot environment anyway) and/or num pad unless you have an F107.

Model Ms are scratchy? What boards are you using? My viewpoints on things like F keys is slightly warped because I need F11 to get into my BIOS's boot menu, and I need a numpad because playing games like System Shock without it is super terrible for the many keypads in the game.

Ms are scratchy _compared to Model Fs_. I've an NIB SSK, and have had many Ms of various models and vintages pass through my possession. None is as good as an F in the smoothness of travel or, of course, the sharpness of click. Fs are just so much nicer.

Compared to modern made MX switches, however, Ms aren't so bad.

As for Model F's layouts, I myself couldn't improve on my OG Kishsaver:



Not all Fs are dorky XTs, just most of them. And if you count Ellipse's modern remakes, maybe even that's changing now…

Out of the boards I have it seems to be more down to how well worn the keyboard itself is, I've had M's smoother than the average F and incredibly scratchy Model F's. However, I'll admit that my smoothest buckling spring board is my F AT, which is buttery smooth.

Muirium wrote: 13 Mar 2023, 16:31 Ms are scratchy _compared to Model Fs_. I've an NIB SSK, and have had many Ms of various models and vintages pass through my possession. None is as good as an F in the smoothness of travel or, of course, the sharpness of click. Fs are just so much nicer.

Compared to modern made MX switches, however, Ms aren't so bad.

As for Model F's layouts, I myself couldn't improve on my OG Kishsaver:

Spoiler:

Not all Fs are dorky XTs, just most of them. And if you count Ellipse's modern remakes, maybe even that's changing now…

Compared to Fs, yeah they're scratchier. As for layouts, I really don't know how people can survive without F keys, a numpad, arrow keys, a delete key, Print Screen, and the nav commands.

daemonspudguy wrote: 14 Mar 2023, 01:00 I really don't know how people can survive without F keys, a numpad, arrow keys, a delete key, Print Screen, and the nav commands.

We don't, they're all still there…



My Kishsaver doesn't have the front facing legends, but I've had the HHKB navigation layer burned into my muscle memory for many years now.

daemonspudguy wrote: 13 Mar 2023, 16:12 Model Ms are scratchy? What boards are you using? My viewpoints on things like F keys is slightly warped because I need F11 to get into my BIOS's boot menu, and I need a numpad because playing games like System Shock without it is super terrible for the many keypads in the game.

A square badge M from 86, one board from every year after up to and including 89 and a Unincomp Mini M. I prefer just about every other popular vintage switch (and a few modern ones) in terms of feel.

Never encountered an F that wasn't as smooth as butter yet, though my repro F77s needed a little wear-in I think. I've probably been lucky though in that all of my vintage Fs have all been in very good shape for their age.

F11 would normally be mapped to something like "-" on another layer, in the rare cases you need it. If I used F11 in a long string of other keys I might be bothered by this (which is why I think no dedicated arrow keys is a no-go for me) but since it is just two keys, that's fine. I type numbers with the number row, but I have pretty long fingers.

Print screen is kind of vestigial at this point. Windows+shift+s brings up the snipping tool so you can just select a part of your screen to immediately copy to your clipboard, and you're done. I do always have a dedicated delete key, especially since on my F ATs I always have num lock off anyway.

I don't use Windows, and just having a single print screen key is more convinient anyways. I also think that Big-ass enter plus 1 unit backspace is almost useless, and I had to use that layout for a long time because a lot of cheap keyboards have it for some reason, so the AT layout is definitely not my thing. The XT layout is an affront to humanity.

And I'm in the terminal enough times that not having arrow keys is not an option.

I press the arrow keys surely hundreds of times a day. And yet they're not dedicated keys. Spooky, eh?

daemonspudguy wrote: 15 Mar 2023, 01:35
not having arrow keys

Huh?
122-key terminal keyboards have a plethora of dedicated arrow and navigation keys, and can be mapped for more.

fohat wrote: 15 Mar 2023, 14:46

daemonspudguy wrote: 15 Mar 2023, 01:35
not having arrow keys

Huh?
122-key terminal keyboards have a plethora of dedicated arrow and navigation keys, and can be mapped for more.

I was replying to Muirium