Cheapest custom backplate?

[loudaslife]

What are the cheapest options for a one-off backplate for Cherry switches? Basically I want a modified Planck layout with an extra row for numbers.

I contacted Jack Humbert, the person who designed and sells Planck kits (really nice guy). His supplier has a MOQ of 10 pieces for any custom work, and I don't think enough other people would be interested. The DIY resources thread here mentioned Big Blue Saw, Front Panel Express, and eMachineShop, but the lowest estimate from any of them was $70 + shipping. I'm still waiting on estimates from a local waterjet shop, but I'm 90% sure it'll be as expensive or worse.

It seems that unless I do a multilayer recessed mount (like the Ergodox), the only viable materials would be aluminum or steel. Since the MX switch housing is designed specifically for a 1.5mm plate, metal is the only thing sturdy enough at that thickness. I wouldn't mind doing some of the work by hand, but I don't have the tools to accurately cut metal that thick. My CAD file is already stripped down to the most basic functional design, just squares cut out of a rectangle, so I can't cut any more costs in machining time.

I'm also waiting on quotes for laser cutting, since 1.5mm metal is right at the outer edge of doable for most machines. I'm not sure if that would be any cheaper than waterjet or milling though. Any thoughts?

[Moralless]

Your main option to get a cheap custom plate is to just keep requesting for quotes to any lasercutting/ waterjet shop you can see and just going with the cheapest one.

You're not limited to just steel and aluminium. Acrylic is also a viable option for a plate and most likely also the cheapest, you just have to get it cut at a higher thickness than you would with a steel or aluminium plate (I forgot what thickness, I want to say 5mm but I'm not too sure) and all you have to do is to hot glue the switches onto the acrylic plate. The reason why acrylic plates aren't as widely used as steel or aluminium plates is due to their flexible nature, this wouldn't really be a concern for a keyboard as small as the Planck even with the extra row.

[heedpantsnow]

Let us know what you decide.  Good luck!

[jacobolus]

If you're going to hand wire it, a 1/16" layer of laser-cut acrylic sized so the switches clip in works great, as long as you back it by a thicker piece of acrylic with holes cut a bit bigger (e.g. 1/4" is very rigid and sturdy).

[jdcarpe]

One-offs are expensive. That's just a fact.

If all you're wanting is a 12x5 matrix, maybe you can find a broken Tipro for cheap and cut the plate down to the size you want.

[CPTBadAss]

A local makerspace or library may have shop machines that you could use. I'd check that.

[heedpantsnow]

One-offs are expensive. That's just a fact.

If all you're wanting is a 12x5 matrix, maybe you can find a broken Tipro for cheap and cut the plate down to the size you want.

This is actually a really good idea.  Buy a cheap donor board, harvest the switches and cut the plate.

[loudaslife]

If you're going to hand wire it, a 1/16" layer of laser-cut acrylic sized so the switches clip in works great, as long as you back it by a thicker piece of acrylic with holes cut a bit bigger (e.g. 1/4" is very rigid and sturdy).

This is a great idea. Since the thicker backing layer won't be visible or require much precision, I could probably get away with cutting it by hand on my scroll-saw. I could maybe just make it out of the same model-grade plywood I'm planning to make the case from.

If all you're wanting is a 12x5 matrix, maybe you can find a broken Tipro for cheap and cut the plate down to the size you want.

Well, I still want the 2x space bar is the problem. I'll keep looking, but I don't think there are layouts with just a single 2x key and a surrounding grid of 1x keys. Still a good idea though.

A local makerspace or library may have shop machines that you could use. I'd check that.

I've never heard of a Library having shop equipment. I wish ours did. My town isn't very big, so our makerspace doesn't have any automated equipment aside from a couple of 3d printers. I know at least 1 highschool and several colleges with laser-cutters and mills, but there's no easy way to use them without actually being in a class or personally knowing one of the staff.

[dorkvader]

I would say any price under $100 is excellent (especially if you do all the finishing yourself. Took about 5 hours to sand the plate.. Don't be afraid if everyone quotes you higher though.

[loudaslife]

get it cut at a higher thickness than you would with a steel or aluminium plate and all you have to do is to hot glue the switches

After putting a lot more thought into the whole project, I think this will be the easiest option. Now, my next question.

Can I use the same switch hole template for this method? I'm assuming that the standard 14mm by 14mm square won't work, since the plastic "clips" will continue to push against the inside edge of the hole and possibly pop the switch back out. Or will it?

[jacobolus]

Can I use the same switch hole template for this method? I'm assuming that the standard 14mm by 14mm square won't work, since the plastic "clips" will continue to push against the inside edge of the hole and possibly pop the switch back out. Or will it?

The plastic clips won’t properly clip in, but that’s fine. The clips will bend out of shape, making them less effective if you want to transplant the switches into another keyboard, but if you’re gluing them you probably aren’t too worried about that.

[Findecanor]

You're not limited to just steel and aluminium. Acrylic is also a viable option for a plate and most likely also the cheapest, you just have to get it cut at a higher thickness than you would with a steel or aluminium plate (I forgot what thickness, I want to say 5mm but I'm not too sure) and all you have to do is to hot glue the switches onto the acrylic plate.

You would have to glue them because above 1.7 mm the switches won't be able to snap onto the plate - they will only be force-fitted in.
An alternative would be to make two or more plates of 1.5 mm thickness and glue them together in a sandwich with the holes slightly different at the top layer from the lower layers.
However, if you use Cherry MX Clear and want to allow the keycaps to be changed then you might want to use glue in either case because the MX Clear's stems are a bit tighter than others - it is very hard to pry off certain keycaps from them. (PBT DSA for instance)

If all you're wanting is a 12x5 matrix, maybe you can find a broken Tipro for cheap and cut the plate down to the size you want.

Well, I still want the 2x space bar is the problem.

I was to about to suggest a POS (point-of-sale) keyboard too. There are more POS manufacturers than Tipro. Access-IS for instance.
POS keyboards often come with 2×1 keys that span two switches, and those are almost as stable as a regular key. You could remove the spring from one of the switches, but it is otherwise common to have more resistance in the space bar.
Cherry's own keyboards use special switches in the space bars that are the same as the other switches except with a stronger spring. these are the MX Green, Grey and Dark grey variants.

As a matter of fact... You might not even need to build a custom keyboard. POS keyboards in sizes close to what you are looking for already exist, and they often have NKRO and are very programmable.
I have a broken Access-IS AKE072965/1 that is 12×6 layout that I had planned to salvage switches from, but just the cost of posting it (from Europe) could exceed what you might be able to get a working one for on eBay in the US.

[The_Beast]

I would say any price under $100 is excellent (especially if you do all the finishing yourself. Took about 5 hours to sand the plate.. Don't be afraid if everyone quotes you higher though.

Depends on the people you know...

[loudaslife]

you might want to use glue in either case because the MX Clear's stems are a bit tighter than others - it is very hard to pry off certain keycaps from them. (PBT DSA for instance)

It'll probably be PBT DSA on Reds, but I would go the extra mile and glue them regardless of the caps or switch. Hot-glue is easy to undo if need be.

My plan at this point is to do the whole thing, plates and case, out of laser-cut 1/8 plywood. The material itself is dirt-cheap, and relatively fast (cheap) to cut. I also really love the look of laser cut wood, something about the burnt edges is aesthetically pleasing to me. Another pro is that I have far more woodworking tools at home if I need to modify it. This plan still hinges on if the Laser doesn't end up being too expensive, still waiting on reply emails for that.

For the structure, the top 2 layers will both be the switchplate, for a full 1/4" of support. Might be a tad on the overkill side for such a small keyboard, but I want dem solid feels. Then, an empty shell layer for routing wires and diodes. The bottom will just be a solid rectangle. I'll have to do some creative chiseling afterwards to get the Teensy 2.0 to fit, but I'm sure it'll work out. 1/2" thick is pretty acceptable. I still need to work out how the stabilizers will mount, but that's hard to do without one here to measure.

[tjweir]

One-offs are expensive. That's just a fact.

If all you're wanting is a 12x5 matrix, maybe you can find a broken Tipro for cheap and cut the plate down to the size you want.

Ha, I did not think of this, and I have a 128 Tipro plate doing nothing. 

Problem solved, thanks JD.