DIY plate dimensions

[DonnyD]

Officially MX switch is 14mm square( where plate meets switch). But on swillkb builder, it makes 13.9995 to me. Is it too small difference to fit snugly ? I think its needs to be smaller, like 13.98 or something close to that so switch fit snugly. I measured with digital calipers and it showed about 13.95-13.98. Should I make about 13.98, leave 13.9995 ir just 14mm and trust in little clips on the switch itself ? Keyboard will be handwired, so no additional stability from the PCB. Maybe those who built plate will now better, idk really...

[Findecanor]

Some builders glue their switches in place to prevent them from being pulled out.

One thing I tried was to mount each switch in the plate, open them up and place a small plastic card inside the clips on the pin side, thus preventing the clips from being pushed inwards. This made one side of the the switches much harder to get out. I did this while also lubricating them so it was not much extra work.

[DonnyD]

I am not planning to open them up, so I guess I will make 13.98 hole and try that. If its too small, some filing always an option. If not, hot glue will help.
Would be great if someone could precisely measure some mass-produced plate switch mounting hole.

[xondat]

14x14mm is snug. Swill only does that because it uses floating point to work out the plate.

The clips are more for vertical fitment, so make sure the plate is 1.5mm.

Work with a place that will make stuff to nice tolerances. 14x14x1.5 works perfectly.

[DonnyD]

Okay, thanks !! So I will make 14mm square and wont be bothered with uneven numbers I am building plate from scratch, so 14mm will help a bit. Should I share my plate when I am done (Tada68-based plate) ?

[pngu]

Hey, I quickly grabbed my calipers to measure the very snug XD75 plate I have floating about and it reads 13.94, I guess that's within the margin of error to 14.00 for both my admittedly cheap calipers, the measuring method and the laser cutting job. Make sure you account for kerf (the breadth of the cut) with the laser cutting service of your choice!

[DonnyD]

Plate will be cnc machined, so should I leave 14mm or lower to 13.96 or smth ?
I will be making cnc machined case with built in plate (reverse from traditional case; pcb would go from bottom of the case (if there would be psb)). So my plate would be 3mm with cutouts for switch clips (photo in my another post, but whatever).
When cutting with cnc manufacturer accounts kerf, i think/hope

[pngu]

It's probably best to inquire with the machine operator and tell him that you have very low tolerances and need these exact measurements. The datasheets for MX switches list a tolerance of +/- 0.1mm but the switches 100% will not sit snug in 14.1mm cuts.

I just grabbed my calipers again, the cuts of a QPad MK50 plate measure 14.02mm and the switches sit VERY loose compared to the XD75.

The cuts on an old Wyse terminal are 13.96 and the switches still come off when taking off keycaps, but the switches themselves are otherwise mounted firmly.

That's all the input I can provide, bear in mind that my calipers themselves aren't lab-grade and in doubt it's probably better to trust swill's tool or look at others' handwired keebs made using it.

Edit: There's also inconsistency among switch manufacturers. Gaterons and Kailh BOX switches (atleast those that I have available) seem to be slightly larger and thus sit more firmly than OG Cherries.

[DonnyD]

I am using Cherry MX, so in theory it should be more consistent. I think i will stick to 13.95 and tolelarce of +-0.1mm.
Much thanks for information, it was very helpfull !!!

[emenelopee]

If you're using Cherry MX, I wouldn't worry about the 0.00x mm rounding (which would be well beyond any meaningful fabrication tolerances for either the plate or switches), and just make sure you use PCB mount switches. The combination of plate and PCB, once soldered, would give you plenty of snugness, and the PCB mount pins will take care of any rotation that imperfect plate holes may not cover.

Having said that, I would err on the side of <14mm as the clips can spring close but not widen. My plate holes were a smidge too large so I painted the chassis to close them a little by a few heavy coats of spray. Kailh switches don't have PCB mount pins which is generally a pain as PCBs are at a much higher tolerance than steel plates and much better for alignment.