deskthority

I'm slowly coming back from the 2025.
Still very tired but can do stuff for maybe an hour-two a day.
Here's what I found so far:
1) Brother model M and IBM model M stem internal cavities are identical - despite 5 mm length difference and significantly different stem appearance.
2) Buckling spring ...

I'd cut off the protruding part with a sharp knife - leaves space to later fasten those back later with a short self-tapping screw.

MG Chemicals 843AR.
I resin-printed a flipper, cured, and then painted as thinly as I could. Ideally, I think, would be to paint before curing and then covering with a thin layer of liquid resin, to prevent conductive stuff from flaking off.

They work. Printing from normal plastic and painting with silver conductive paint also works.

After a slight delay, I modelled and printed a first working Brother Buckling Spring unit (it's scratchy as hell because layers, but it clicks).

brother.jpg

It really looks like BBS is force-buckling: the stem pushes on the flipper, slightly rotating it, triggering buckling towards rotation ...

Some care needs to be taken pulling off keycaps - look at the photos of the switch stem to better understand which direction to pull.
Otherwise, beamspring is easier to assemble/disassemble than model F.

Also, beamspring is not protected from debris ingress - people used saran wrap for a membrane ...

I guess so - no other place to go, really. You should, however, remove all keycaps before attempting reassembly.

Can anyone give me hope of fixing this without taking the keyboard apart again? :roll:


I don't think so. But if you, when assembling it, lay the top plate not on the table, but on some supports that will leave barrels hanging, and use clamps like https://www.amazon.com/dp/B097P8L5TV (get the ...

Not saying the Classic or Hybrid were bad, they just didn't feel as tactile. It might just be how the rubber ages too. I've heard they stiffen with age and that probably affects the tactility. Of course my Hybrid didn't feel as tactile as my Classic. So, there are differences between their new ...

AndyJ wrote: 12 Mar 2025, 00:55 Actually, older (some 1920s-1930s) Cadillacs had pinstriping. So did some European luxury cars. All done by hand.

Yeah. Damn car dealers use them to bump the price $100-$200-whatever. Totally not worth the money but you literally can't opt out. This and painting tires black.

worst case you have a dead GPIO - in which case you'll likely need to replace controller. But yes, far more likely it's a bad solder joint.

Debris under the keys? Or inside the switches even?
My T420s lived thru 3 keyboards - all of them eventually stopped registering a key or two - and eventually cleaning them with canned air (CAREFUL, high-pressure air can rip off your keycaps!) stops working for some reason.

If laptop is still under ...

One can't "AI" without a "keylogger" and can't sell a new keyboard without "AI" - so we'll soon find "keyloggers" (real or imaginary) in every mass-produced keyboard. Like "FULL NKRO" before and "hall effect switches" and "8K" today.

Also that guy is dumb as a cork - keypress statistics isn't a ...

There's not much value in the replica - only high initial price. I disassembled one of those and internally, QC is nonexistent. I'm actually surprised there are no reports of broken USB cables yet.

I can repair it for cost of the parts - but I'm in Seattle, so shipping might be expensive. PM me if ...

OK, I've got to measuring my fleet of Fs.
XT: R290
AT: R290
F122: bottom plate R290 (or slightly smaller), top plate even smaller than R290. NOTE: F122 is the only one that doesn't close with barrels not populated. So this is likely on purpose, to create more pressure in the middle of the plate ...

Yes please! Photos, tech drawings - whatever you are comfortable sharing. This is pretty interesting project and truly herculean effort.

Borrowed that 5576.
Just drove back from California. Hands are too shaky to make any measurements (also I'm basically waiting for the nervous system to understand that trip is finished and let me sleep) - so the measurements will follow in couple days - but for now, here's a sneak peek:
PXL ...

How did you build the case and what's that thing in the middle - relay? Also, is it wired or wireless, and if wireless - how did you implement the antenna?

idollar wrote: 20 Feb 2025, 11:56 I feel that every day the keyboard gets better.

When you have chance to disassemble - please find the places that are shiny/worn. Might provide insight into what contributes to the feel.

This is a set of convex and concave curvature gauges, R290 to R330. R315 is there because value calculated from the whole backplate gave me R315.
PXL_20250219_040552976.jpg

Turns out, the keyboard part (R2 to R6) is R310, and the upper part is >R330, may be >R400 - at least on my model M ...

[*] The plastic barrel plate had big holes where the screws had to come in. They would not create any pressure, leaving the plastic barrel plate lose at this very point. I used some filament and heat, applied with a cheap solder, to first fill the hole to then drill (with a dremel) a new hole ...

These flippers are less conductive than the original ones. I had to reduce the threshold in the Leyden Jar firmware. I am typing with activation offset of 7 (instead of the 20 which I have been using with my "regular" FSSK.

Congratulations! I specially approve of the extra step you took to ...

..I tried photogrammetry to make a 3d scan of the flipper, but developers nowadays are too lazy to write anything without CUDA, so I failed. If anybody wants to help - I can send you the photos and you can use colmap (I hope) to create the model.
I only got to "point cloud" step, which is basically ...

Batch 3 was ruined by washing in the hot water on internet advice. So here's batch 4:
batch3.png

numbers are elevation at rest, in degrees.
5 is whisper-quiet, but also almost linear feel. The spring is buckling, don't get me wrong, but almost imperceptible, even with original barrel+stem. Rarely ...

I have two real IBM Model F boards, but I never did use them as my primary keyboard, one being for my IBM 5150 and the other being that annoying AT layout, so it's perhaps not fair to compare them. They are both awesome though, and the reason I was interested in the F104 in the first place.


If ...

Built to last months, not decades

LOL. But let's just wait until those beam springs accumulate 50k keypresses, that storm will be way larger.

@mbarszcz, can you post a photo of the keycap insides? There are 4 "corners" of each keycap which actually stabilize the keycap within the barrel, I ...

pull all the key caps off.
Make sure flippers move freely inside their barrels and don't protrude outside of the barrel into the area that will be occupied by PCB - it's quite easy to dislodge them and either break them or simply wedge them into the barrel so they can't move.
Then use however many ...

I accidentally silent buckling spring. Sadly, it's LINEAR.
Turns out, tactility turns out to be generated by flipper dropping on PCB and vibrating the hell out of the whole mechanism.
PXL_20250204_013712766.jpg

You may notice there's a window where the spring SUPPOSEDLY hits the barrel. SURPRISE ...

TIL "Alps buckling spring" is a thing: https://www.paulbramhall.uk/bits-n-bobs/keyboards/1990-alps-sm-101/spring-forward-with-the-alps-sm-101-exploring-a-rare-and-uncommon-buckling-spring-keyboard/
Shorter spring is a benefit - I was able to shorten the barrel to 15mm in height, but cherry MX switch ...

I looked at Elegoo Saturn 4 Ultra. I would not go for it.
Me neither, knowing what I know today! But alas, missed my return window with surgery and all that. I'll make it work, just disappointed.

I personally do not like also the two level build plate. Cleaning resin from it must be a pain ...