How thick can a Cherry MX plate be?

[njbair]

I'm thinking about milling my own unibody aluminum numpad. Thing is, I can't get very thin on the plate part because I'm milling it. This would be a hand wired pad (at least for now) so I really need the plate to do its job well.

AFAIK, the limit on thickness is probably 1/16" (1.5mm), because that's about the size of the gap on the little plate clips.

Does anyone here have first hand experience and can weigh in on this?

[nubbinator]

AFAIK the limit is the thickness of the bottom half of the switch if you use Cherry PCB stabilizers and it's 0.06" if you use plate mounted stabilizers.

[njbair]

Hmm maybe I can leave some extra stock in between each row to add some rigidity. Take advantage of the fact I'm milling, and end up with a super solid numpad.

[VinnyCordeiro]

From Cherry MX datasheet:


Answer: 1.5 ± 0.1 mm (1.4 mm to 1.6 mm)

^{PS: imperial system sucks}

[nubbinator]

From Cherry MX datasheet:
(Attachment Link)

Answer: 1.5 ± 0.1 mm (1.4 mm to 1.6 mm)

^{PS: imperial system sucks}

That's assuming no top plate SMD stuff.

[jacobolus]

1/16" is too thick. I’d recommend using 17 or 18 gauge steel, if you can.

If you’re milling aluminum, I recommend milling from the bottom, and having most of the plate be thicker, but milling down to 1.5mm thickness right at the points where the plastic clips will go. Likewise you want a 1.5mm area for costar stabilizer clips to grab.

[njbair]

1/16" is too thick. I’d recommend using 17 or 18 gauge steel, if you can.

If you’re milling aluminum, I recommend milling from the bottom, and having most of the plate be thicker, but milling down to 1.5mm thickness right at the points where the plastic clips will go. Likewise you want a 1.5mm area for costar stabilizer clips to grab.

This is probably how I'll end up doing it. There would be way too much chatter if I tried to mill the whole surface down to 1.5mm, even on something small like a numpad.

[FrostyToast]

The limit for how thick a cherry plate would be is 5mm. If you do this you can't have front mounted smd components.
Sprit made his acrylic plate 5mm.
If you want to do this though you need to cnc a little notch at the top of the plate on the backside so the switch can properly clip in.

[njbair]

So anything thicker than 1.5mm is really depending on the PCB to hold the switches in place, as that's the max for the little retention clips on the switches. I had assumed this was the case for boards like the Ergodox and other acrylic layer boards, but it's nice to know for sure.

I'm kind of starting to like the idea of a thick unibody aluminum top plate, but that would require a PCB. Hmm. Maybe I should do this right and design a PCB/case and post an IC.

[Giorgio]

To reduce noise and vibrations, wouldn't it be possible to add a second, bigger plate, under the first one? The holes of the switches would be bigger, to allow the switches to clip into the first one.

[njbair]

To reduce noise and vibrations, wouldn't it be possible to add a second, bigger plate, under the first one? The holes of the switches would be bigger, to allow the switches to clip into the first one.

This will be a solid piece, but I could accomplish the same thing by milling a wider pocket (like a counterbore) on the back side.

[Giorgio]

I'm planning to use a laser cutting service that quite surely doesn't offer such luxury :-)

I've seen some drawing from a guy that did exactly what you are saying, I will search for those if you are interested. Maybe they were on deskthorithy

To reduce noise and vibrations, wouldn't it be possible to add a second, bigger plate, under the first one? The holes of the switches would be bigger, to allow the switches to clip into the first one.

This will be a solid piece, but I could accomplish the same thing by milling a wider pocket (like a counterbore) on the back side.

[Giorgio]

Maybe it was this
https://geekhack.org/index.php?topic=65747.0;nowap

[jacobolus]

If you’re making a plate out of steel, then there’s no reason to add a second plate below. If you’re making a plate out of acrylic, then two sheets stuck together works great. For MX switches, try to get 1.5mm for the top sheet, as 1/16" is slightly too thick. For Alps switches, a 1/16" plate works okay but you’ll want to cut the holes slightly larger than standard in the top sheet. If you’re going to hand wire, then I recommend using 1/4" or 6mm or similar for the bottom plate. If you have a PCB, then stick with 1/8" or 3–4mm.

Regardless, try to get a test plate cut with holes of several sizes, so you can figure out exactly which works best.

[technomancy]

So anything thicker than 1.5mm is really depending on the PCB to hold the switches in place, as that's the max for the little retention clips on the switches.

It's not uncommon to use hot glue to hold the switches in place for hand-wired boards that use thicker plates. Bit tacky but it gets the job done.

[Melvang]

1/16" is too thick. I’d recommend using 17 or 18 gauge steel, if you can.

If you’re milling aluminum, I recommend milling from the bottom, and having most of the plate be thicker, but milling down to 1.5mm thickness right at the points where the plastic clips will go. Likewise you want a 1.5mm area for costar stabilizer clips to grab.

1/16" will work

1.4 - 1.6 = 0.0551181" - 0.0629921

For aluminum

16g = 0.0508"
15g = 0.0571"
14g = 0.0641"

Here is my source
https://www.unc.edu/~rowlett/units/scales/sheetmetal.html

[Joey Quinn]

1/16" is too thick. I’d recommend using 17 or 18 gauge steel, if you can.

If you’re milling aluminum, I recommend milling from the bottom, and having most of the plate be thicker, but milling down to 1.5mm thickness right at the points where the plastic clips will go. Likewise you want a 1.5mm area for costar stabilizer clips to grab.

1/16" will work

Can confirm, my MA42 uses a 1/16" plate and it works great.

[jacobolus]

Any thickness “works”, especially if you solder everything down to a PCB, or add some hot glue. But 1/16" is thicker than ideal for the plastic clips on MX switches to properly snap to their original shape. 1.5mm is better if you can find it.

As with anything, do your own tests, don’t just rely on narrowly interpreting published datasheets.

[Giorgio]

Just wondering if it could make a difference in terms of noise. There is a lot of difference between a metal switch tester and a keyboard, I wonder if the keyboard can be made more silent adding a plate.

If you’re making a plate out of steel, then there’s no reason to add a second plate below. If you’re making a plate out of acrylic, then two sheets stuck together works great. For MX switches, try to get 1.5mm for the top sheet, as 1/16" is slightly too thick. For Alps switches, a 1/16" plate works okay but you’ll want to cut the holes slightly larger than standard in the top sheet. If you’re going to hand wire, then I recommend using 1/4" or 6mm or similar for the bottom plate. If you have a PCB, then stick with 1/8" or 3–4mm.

Regardless, try to get a test plate cut with holes of several sizes, so you can figure out exactly which works best.

[njbair]

Just wondering if it could make a difference in terms of noise. There is a lot of difference between a metal switch tester and a keyboard, I wonder if the keyboard can be made more silent adding a plate.

If you’re making a plate out of steel, then there’s no reason to add a second plate below. If you’re making a plate out of acrylic, then two sheets stuck together works great. For MX switches, try to get 1.5mm for the top sheet, as 1/16" is slightly too thick. For Alps switches, a 1/16" plate works okay but you’ll want to cut the holes slightly larger than standard in the top sheet. If you’re going to hand wire, then I recommend using 1/4" or 6mm or similar for the bottom plate. If you have a PCB, then stick with 1/8" or 3–4mm.

Regardless, try to get a test plate cut with holes of several sizes, so you can figure out exactly which works best.

A switch tester doesn't have PCB underneath the plate, and the cutouts are usually slightly on the big side just to make sure everything fits. So switch testers tend to be much more rattly than a real board. Switches on PCB-only boards don't rattle, but the boards aren't very rigid. A PCB/plate sandwich is the best of both worlds. The only downsides of adding a plate are that it makes desoldering the switches much more difficult (or impossible, depending on the plate) and it adds cost. But you can effectively change any MX switch type to another type by changing the stems and springs, so there's really no need to desolder. And if cost is a big concern you wouldn't be building your own board. So a plate really makes sense probably 99% of the time.

[mkawa]

Max 16ga

[mkawa]

Oh and keep in mind that lasers tend to leave flash that thickens the edges of a cut. With 80mil thick and 2-3mil cut accuracy I've seen good results, but any tighter or thicker and it would have been pinching the switches. Alum in particular has a tendency to blow out under a laser. Those results were titanium unalloyed