Author Topic: Plate cutouts  (Read 16384 times)

0 Members and 1 Guest are viewing this topic.

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Plate cutouts
« on: Mon, 23 June 2014, 08:48:32 »
I would like to ask out the various cutout shapes I've seen in the various custom plates that have appeared on GeekHack. Below is a drawing with the 4 cutout shapes I have seen.



Here is my understanding of the differences:


         Allows Switch      Can Rotate Mounting
            Modding                  Direction *
---    -----------------     -----------------------
 1             No                       Yes
 2             Yes                      No
 3             Yes                      No
 4             Yes                      Yes


Is this correct?
It seems like the reliefs added to allow for modding would reduce the stability of the mounting, as the lateral reinforcement of the switch decreases. I.e. the switch might be more prone to wobble. Is this true?
Lastly, shapes 2 and 3 are similar, but 2 seems like it may be cheaper to laser cut (less time) at the cost of a bit of stability. Comments?


* for those that allow modding, this means allow rotation and preserve ability to allow modding.
« Last Edit: Mon, 23 June 2014, 10:55:16 by engicoder »
   

Offline strict

  • TKL Zealot
  • Posts: 1921
  • Location: PA
Re: Plate cutouts
« Reply #1 on: Mon, 23 June 2014, 09:25:13 »
There should be no difference between cutout #2 vs #3 in terms of stability. If you look at the sides of a cherry switch there is no plastic material positioned in a way that can utilize the metal "tab" that exists in design #3. Its just extra work for the laser cutter.

IMO, design #2 is the most optimal. The layout is such that almost every part of the switch housing that is designed to rest against the plate will be utilized while still remaining open on the sides to allow for switch modding. Of course design #1 covers the switch as completely as possible but the stability factor should be virtually identical between #1 and #2 due to the design of the switch housing.

I've never seen design #4 offered in my short time here but I can see how it would be useful if you were designing a custom PCB or hard wiring a board together. Outside of those two options, I see no benefit over design #2 or #3 since most PCBs can only have switches soldered in one specific orientation.

Realforce EK45 (Silenced)  |  Realforce 87UW (45g)  |  Realforce 87UWS (Variable)
Filco MJ2 TKL (Cherry Clears)  |  Phantom 87 (78g Gateron Clears)  |  Phantom 86 (67g Zealios)


Offline jdcarpe

  • * Curator
  • Posts: 8854
  • Location: Odessa, TX
  • Live long, and prosper.
Re: Plate cutouts
« Reply #2 on: Mon, 23 June 2014, 09:33:52 »
I've never seen design #4 offered in my short time here but I can see how it would be useful if you were designing a custom PCB or hard wiring a board together. Outside of those two options, I see no benefit over design #2 or #3 since most PCBs can only have switches soldered in one specific orientation.

I designed #4 to have "universal" direction for the holes, as a result of the GH60 Rev.A PCB prototype having 90-degree rotated switches in some locations. I had a few plates made with holes of that design, but I determined that there was just too much room for play, or wobble, within the switch hole that the design really wasn't optimal. Of course, if you use a PCB, and especially one with support for PCB mounting the switches (and use PCB mount switches), the wobble issue becomes moot. But then, at that point, why even use a plate at all?



OP, here is how your post looks on the Nostalgia (default) forum theme:

« Last Edit: Mon, 23 June 2014, 10:55:17 by jdcarpe »
KMAC :: LZ-GH :: WASD CODE :: WASD v2 :: GH60 :: Alps64 :: JD45 :: IBM Model M :: IBM 4704 "Pingmaster"

http://jd40.info :: http://jd45.info


in memoriam

"When I was a kid, I used to take things apart and never put them back together."

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Re: Plate cutouts
« Reply #3 on: Mon, 23 June 2014, 10:50:50 »
OP, here is how your post looks on the Nostalgia (default) forum theme:

Show Image


Oops...alpha error...I will fix that.
   

Offline jdcarpe

  • * Curator
  • Posts: 8854
  • Location: Odessa, TX
  • Live long, and prosper.
Re: Plate cutouts
« Reply #4 on: Mon, 23 June 2014, 10:55:08 »
There should be no difference between cutout #2 vs #3 in terms of stability. If you look at the sides of a cherry switch there is no plastic material positioned in a way that can utilize the metal "tab" that exists in design #3. Its just extra work for the laser cutter.

IMO, design #2 is the most optimal. The layout is such that almost every part of the switch housing that is designed to rest against the plate will be utilized while still remaining open on the sides to allow for switch modding. Of course design #1 covers the switch as completely as possible but the stability factor should be virtually identical between #1 and #2 due to the design of the switch housing.

Agreed. I picked up the design of the #2 hole from plates WFD had made, and I now use those hole cuts for all the plates I design.

The only advantage of design #3 is that people can look at an image (pic, drawing file) and instantly tell that it has the openings for the switch tabs. The design of the #2 holes is such that it's hard for people to tell at a glance that the switch holes have the proper cutouts, as the holes look similar to the Cherry-spec #1 holes.
KMAC :: LZ-GH :: WASD CODE :: WASD v2 :: GH60 :: Alps64 :: JD45 :: IBM Model M :: IBM 4704 "Pingmaster"

http://jd40.info :: http://jd45.info


in memoriam

"When I was a kid, I used to take things apart and never put them back together."

Offline dorkvader

  • Posts: 6284
  • Location: Boston area
  • all about the "hack" in "geekhack"
Re: Plate cutouts
« Reply #5 on: Mon, 23 June 2014, 11:52:10 »
#2 and #3 should allow 90 degree switch rotation, but you can't open it without desoldering, and (to my knowlege) have never been implemented in such a way.

Offline jdcarpe

  • * Curator
  • Posts: 8854
  • Location: Odessa, TX
  • Live long, and prosper.
Re: Plate cutouts
« Reply #6 on: Mon, 23 June 2014, 11:55:21 »
#2 and #3 should allow 90 degree switch rotation, but you can't open it without desoldering, and (to my knowlege) have never been implemented in such a way.

Right. That's why he put this at the bottom of the OP. :)

* for those that allow modding, this means allow rotation and preserve ability to allow modding.
KMAC :: LZ-GH :: WASD CODE :: WASD v2 :: GH60 :: Alps64 :: JD45 :: IBM Model M :: IBM 4704 "Pingmaster"

http://jd40.info :: http://jd45.info


in memoriam

"When I was a kid, I used to take things apart and never put them back together."

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Re: Plate cutouts
« Reply #7 on: Mon, 23 June 2014, 12:15:35 »
@strict @jdcarpe   Thanks for the feedback. #2 FTW  :D

   

Offline Findecanor

  • Posts: 4907
  • Location: Koriko
Re: Plate cutouts
« Reply #8 on: Mon, 23 June 2014, 15:07:47 »
Lastly, shapes 2 and 3 are similar, but 2 seems like it may be cheaper to laser cut (less time) at the cost of a bit of stability. Comments?
If you look at the sides of a cherry switch there is no plastic material positioned in a way that can utilize the metal "tab" that exists in design #3. Its just extra work for the laser cutter.
Yes there is. The side-tabs of #3 do touch the switch's sides, but the corners do it just as much. If the side-tabs were slightly wider than the norm, they would provide more stability than the corners.
Less gaps in the plate would mean less chance of anything falling through the hole down onto the PCB and creating a short and less dust buildup inside the keyboard.

Let me propose yet another shape: an H-shape without the tiny tabs in the corners would have just as many cuts as #2, be just as stable and provide not much more gaps than #3 but it would also allow rounder corners which could possibly make it even cheaper to CNC-mill.
Man must shape his tools lest they shape him
-- Arthur Miller

Offline jdcarpe

  • * Curator
  • Posts: 8854
  • Location: Odessa, TX
  • Live long, and prosper.
Re: Plate cutouts
« Reply #9 on: Mon, 23 June 2014, 15:21:42 »
This is Findecanor's suggestion:




Anyone want to make a plate and test it out?

I'm attaching a drawing file for anyone who is interested.
KMAC :: LZ-GH :: WASD CODE :: WASD v2 :: GH60 :: Alps64 :: JD45 :: IBM Model M :: IBM 4704 "Pingmaster"

http://jd40.info :: http://jd45.info


in memoriam

"When I was a kid, I used to take things apart and never put them back together."

Offline 0100010

  • Posts: 1127
  • Location: DFW, TX, US
  • Not Sure
Re: Plate cutouts
« Reply #10 on: Mon, 23 June 2014, 15:34:33 »
Doesn't the Cherry plate mount switch index off the corners though?

EDIT : I seem to remember that when playing with this model in Sketchup.

« Last Edit: Mon, 23 June 2014, 15:54:41 by 0100010 »
  Quoting me causes a posting error that you need to ignore.

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Re: Plate cutouts
« Reply #11 on: Mon, 23 June 2014, 17:37:59 »
Let me propose yet another shape: an H-shape without the tiny tabs in the corners would have just as many cuts as #2, be just as stable and provide not much more gaps than #3 but it would also allow rounder corners which could possibly make it even cheaper to CNC-mill.

This seems reasonable. I am going to look at the dimensions a little more carefully.

Most of the plates the community is making are laser or waterjet cut, so the cost is based on cutting time + materials. Cutting time is increased by distance and number of corners (laser cutter speed decreases for corners). As the distance is not largely different between the shapes, number of corners takes precedence. Here are the number of corners for each..


68835-0

Cutout      Corners   
---------   ----------
1                  4
2                 12
3                 20
4                 36
5                 12


As far as the side notch in #5 , I measure a switch top and the small tabs are 3/32 or 0.94 inches and the center area between the tabs is 0.25 inches. The drawing above reflects the dimensions, although I reduced the side notch in 5 to 0.24 inches to allow for clearance of the tabs on the switch top.
Working on a detailed drawing now.
« Last Edit: Mon, 23 June 2014, 17:50:51 by engicoder »
   

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Re: Plate cutouts
« Reply #12 on: Mon, 23 June 2014, 22:03:39 »
Anyone want to make a plate and test it out?

I'm working on a plate (hence the questions). I will give it a try.
   

Offline jacobolus

  • Posts: 3661
  • Location: San Francisco, CA
Re: Plate cutouts
« Reply #13 on: Mon, 23 June 2014, 23:02:04 »
Doing lots of modifications to switches without desoldering seems like a pretty niche use case to me (itís not like desoldering is especially hard), so personally Iíd just as soon stick with #1, unless making a keyboard aimed at geekhack folks.

As for cost, Iím guessing that on a laser cutter adding the little cutouts is a pretty negligible difference. Iím not sure about waterjet pricing.
« Last Edit: Mon, 23 June 2014, 23:04:03 by jacobolus »

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Re: Plate cutouts
« Reply #14 on: Tue, 24 June 2014, 06:44:32 »
Doing lots of modifications to switches without desoldering seems like a pretty niche use case to me (itís not like desoldering is especially hard), so personally Iíd just as soon stick with #1, unless making a keyboard aimed at geekhack folks.

Probably very true. I suppose its like NKRO, very few actually need it, but its so shiny. ;-)
   

Offline qwack

  • Posts: 310
  • Location: ISO FR
Re: Plate cutouts
« Reply #15 on: Thu, 26 June 2014, 10:09:25 »
This is Findecanor's suggestion:

Show Image



Anyone want to make a plate and test it out?

I'm attaching a drawing file for anyone who is interested.

I'm interested in a cutout that is simpler to machine, so I gave it a try. It's hand-made, so it's pretty rough, but I think it's enough to get an idea of the viability of the idea:







As intended, the tabs on the sides do provide some lateral support. They are 5mm wide, as per the specs you proposed, and I don't think they could be made narrower. 6mm would provide more support (not sure it's necessary though), but may be problematic if you want a milled plate with useable cutouts to open the switch.

Pure Pro w/MX Red - [review]

Offline 0100010

  • Posts: 1127
  • Location: DFW, TX, US
  • Not Sure
Re: Plate cutouts
« Reply #16 on: Thu, 26 June 2014, 15:21:10 »
How much rotational play is present with that switch?
  Quoting me causes a posting error that you need to ignore.

Offline qwack

  • Posts: 310
  • Location: ISO FR
Re: Plate cutouts
« Reply #17 on: Thu, 26 June 2014, 15:32:15 »
None at all.

Pure Pro w/MX Red - [review]

Offline trishume

  • Posts: 17
  • Location: Canada
    • My Website
Re: Plate cutouts
« Reply #18 on: Fri, 27 June 2014, 16:35:57 »
I laser cut a few of these cutouts onto some cheap eight inch hardboard/masonite to test them out, including the new H-shaped one. They are pretty loose though since hardboard isn't a very precise material for laser cutting, the burning made the cuts wider than I wanted. With the loose holes the one with both corners and tabs is the most stable, with the H cutout being the least stable.

I've attached some pictures although I'm not sure they will show much. The one with corners and tabs has very little lateral and rotational play unlike the others, but all the holes are very loose vertically since the board is too thick for the switches to snap on and not tight enough for a good friction fit. The switches don't fall out but you can't pull keycaps off of them without them coming out.

I used jdcarpe's CAD files for all three cutout types, cut on an Epilog laser with 15% speed and 100% power.

Takeaways:
- Hardboard is decent for prototyping plates, really cheap, but too imprecise for actual keyboards.
- Without tight tolerances,  the H shaped cutout doesn't hold the switches as well as the others.

Offline Findecanor

  • Posts: 4907
  • Location: Koriko
Re: Plate cutouts
« Reply #19 on: Fri, 27 June 2014, 16:47:23 »
Nah, well. Now we know that. Thanks qwack and trishume for testing!

I still think though that if the plate is made with high tolerances the top and bottom edges by themselves should prevent all twisting and the side tabs should only prevent the switch from being rocked sideways.
However, these are templates for DIY guys/"makers" and makers seldom get to do proofs before production - because we most often do one-offs - so fitness when the tolerances are loose is still important.
« Last Edit: Fri, 27 June 2014, 17:02:04 by Findecanor »
Man must shape his tools lest they shape him
-- Arthur Miller

Offline qwack

  • Posts: 310
  • Location: ISO FR
Re: Plate cutouts
« Reply #20 on: Fri, 27 June 2014, 17:16:35 »
I still think though that if the plate is made with high tolerances the top and bottom edges by themselves should prevent all twisting and the side tabs should only prevent the switch from being rocked sideways.

Yes, it basically comes down to that. I actually filed down the top and bottom edges to the right specs, which is why the switch sits perfectly tight in the cutout. It may very well be a different story if I widened it just a bit (I may try to see how much extra material removal is too much).

Pure Pro w/MX Red - [review]

Offline jacobolus

  • Posts: 3661
  • Location: San Francisco, CA
Re: Plate cutouts
« Reply #21 on: Fri, 27 June 2014, 18:42:29 »
I laser cut a few of these cutouts onto some cheap eight inch hardboard/masonite to test them out, including the new H-shaped one. They are pretty loose though since hardboard isn't a very precise material for laser cutting, the burning made the cuts wider than I wanted. With the loose holes the one with both corners and tabs is the most stable, with the H cutout being the least stable.
Why canít you just account for the width of the laser when you make your design? I donít think ďimpreciseĒ is the right word here. Or did you make a bunch of test cuts sending the identical shape to the laser and find that the result was different each time?

Offline trishume

  • Posts: 17
  • Location: Canada
    • My Website
Re: Plate cutouts
« Reply #22 on: Sat, 28 June 2014, 09:55:47 »
Why canít you just account for the width of the laser when you make your design? I donít think ďimpreciseĒ is the right word here. Or did you make a bunch of test cuts sending the identical shape to the laser and find that the result was different each time?

This might work. I just cut the pattern twice, both times ended up very similar. I might end up measuring the width with my calipers and adjusting the model if I end up with the same problem when I try it with acrylic.

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Re: Plate cutouts
« Reply #23 on: Sun, 29 June 2014, 07:57:52 »
I think the center portion on jdcarpe's model needs to be wider to create more contact area with the side of the switch.

I made some measurements and drew up the following. The left is the final dimensions. The right allows for 0.008 laser kerf in 1/8 acrylic (not sure if trishume's is same).

69397-0

@trishume  I am curious as to how the cuttings time compared for the three shapes you cut.
« Last Edit: Sun, 29 June 2014, 08:02:39 by engicoder »
   

Offline trishume

  • Posts: 17
  • Location: Canada
    • My Website
Re: Plate cutouts
« Reply #24 on: Mon, 30 June 2014, 08:22:26 »
I think the center portion on jdcarpe's model needs to be wider to create more contact area with the side of the switch.

I made some measurements and drew up the following. The left is the final dimensions. The right allows for 0.008 laser kerf in 1/8 acrylic (not sure if trishume's is same).

@trishume  I am curious as to how the cuttings time compared for the three shapes you cut.

I didn't measure the time (I should have) but I think all three were very similar, the laser has to move slowly enough to cut so it doesn't slow down much for turns.

I was using a 40W epilog laser on hardboard. I think the kerf was pretty high since the cut burned away material at the edges, it would probably be better with acrylic. I might try again with acrylic and with your new model as well, I originally used the model jdcarpe posted.

Offline trishume

  • Posts: 17
  • Location: Canada
    • My Website
Re: Plate cutouts
« Reply #25 on: Fri, 04 July 2014, 10:06:10 »
I just laser cut some test patterns in 6mm/0.2in acrylic. I tried them with varying dimensions so that I could test the fit of the switches. When I directly printed jdcarpe's cutouts they were too loose so I tightened the cutouts by varying amounts. It turns out insetting the edges by 0.2mm gave me results that fit the spec so that is the reference point. Here are the fit results:

-0.15mm : Very loose fit, some play, can't pull keycap without pulling out switch. Keyboard made like this would fall apart easily if it didn't have a PCB.
-0.10mm : Same as -0.15mm maybe imperceptibly tighter
0.00mm : Cherry Spec. Holds switches to be very robust without a PCB. Almost zero play. Still not tight enough to pull a keycap without pulling out switch.
+0.05mm : Very nice solid fit. Can pull a keycap off without pulling switch.
+0.10mm : Quite tight without stressing switch. Can easily pull keycap off without feeling switch move. Takes effort to pop out. I'm going to use this for my board since it won't have a PCB.

When they are tight enough, all the cutout shapes perform similarly. At spec all have almost no play and are as tight as each other. They also cut in similar amounts of time. I'm planning on using the normal ones with two tab cutouts for my board since they look the most robust to loose tolerances.

I've attached an image of my test plates. The Sharpie numbers are how far I inset the edges from jdcarpe's model so the holes marked 0.2 are the cherry spec.

Edit: The measurements in the list already account for laser kerf and were measured with calipers against the cherry spec of 0.55in. The listing that says 0.00mm was cut from a model that was inset by 0.02mm.
« Last Edit: Sat, 05 July 2014, 08:55:56 by trishume »

Offline engicoder

  • Thread Starter
  • Posts: 721
  • Location: North Carolina
Re: Plate cutouts
« Reply #26 on: Fri, 04 July 2014, 10:45:19 »
Thanks for all the work.. Great info. The inset allows for the kerf of the laser, so it makes sense that your 0.10mm inset was about right, since that is probably the kerf of the laser at 6mm.

When you say you plan to use "the normal ones with two tab cutouts" do you mean #3 from the early drawings?

   

Offline jacobolus

  • Posts: 3661
  • Location: San Francisco, CA
Re: Plate cutouts
« Reply #27 on: Fri, 04 July 2014, 13:45:32 »
I just laser cut some test patterns in 6mm/0.2in acrylic. I tried them with varying dimensions so that I could test the fit of the switches. When I directly printed jdcarpe's cutouts they were too loose so I tightened the cutouts by varying amounts. It turns out insetting the edges by 0.2mm gave me results that fit the spec so that is the reference point. Here are the fit results:
Can you measure the actual final dimensions with some calipers? Different laser cutters might have different kerf, so folks probably want to compensate for that.

Also, how thick is your acrylic? If itís thicker than 1/16", youíre going to be putting permanent stress on the little plastic clips that are supposed to grab the underside of the plate. The thickness of the acrylic makes some difference in how big the optimal switch hole is.

Offline trishume

  • Posts: 17
  • Location: Canada
    • My Website
Re: Plate cutouts
« Reply #28 on: Sat, 05 July 2014, 08:51:58 »
I realize now that I didn't properly communicate that the list of results was as measured with calipers against the Cherry specification. Meaning I already subtracted my laser kerf, the listing that says 0.00mm was cut from a CAD model that was inset by 0.2mm.

Yes I do intend to use #3.

Offline sypl

  • Posts: 115
Re: Plate cutouts
« Reply #29 on: Wed, 11 February 2015, 16:04:59 »
So what's the size of the plain type#1 square mount holes? .55*.55?

Offline jacobolus

  • Posts: 3661
  • Location: San Francisco, CA
Re: Plate cutouts
« Reply #30 on: Wed, 11 February 2015, 16:10:36 »
0.551 Ī .002 inches, with a 0.012" max corner radius
plate thickness 0.06 Ī 0.004 inches
http://media.digikey.com/pdf/Data%20Sheets/Cherry%20PDFs/MX%20Series.pdf

Offline sypl

  • Posts: 115
Re: Plate cutouts
« Reply #31 on: Wed, 11 February 2015, 22:02:30 »
0.551 Ī .002 inches, with a 0.012" max corner radius
plate thickness 0.06 Ī 0.004 inches
http://media.digikey.com/pdf/Data%20Sheets/Cherry%20PDFs/MX%20Series.pdf

Thanks!

Offline Hak Foo

  • Posts: 1268
  • Make America Clicky Again!
Re: Plate cutouts
« Reply #32 on: Wed, 11 February 2015, 23:47:35 »
I would like to ask out the various cutout shapes I've seen in the various custom plates that have appeared on GeekHack. Below is a drawing with the 4 cutout shapes I have seen.

(Attachment Link)

Here is my understanding of the differences:


         Allows Switch      Can Rotate Mounting
            Modding                  Direction *
---    -----------------     -----------------------
 1             No                       Yes
 2             Yes                      No
 3             Yes                      No
 4             Yes                      Yes


Is this correct?
It seems like the reliefs added to allow for modding would reduce the stability of the mounting, as the lateral reinforcement of the switch decreases. I.e. the switch might be more prone to wobble. Is this true?
Lastly, shapes 2 and 3 are similar, but 2 seems like it may be cheaper to laser cut (less time) at the cost of a bit of stability. Comments?


* for those that allow modding, this means allow rotation and preserve ability to allow modding.


One side benefit of the Type 2 hole is that it can accomodate ALPS style switches.  MX switches are square, but ALPS are slightly off-square.
Overton130, Box Pale Blues.

Offline okaa

  • Posts: 5
Re: Plate cutouts
« Reply #33 on: Sun, 08 April 2018, 08:01:27 »
All cutout designs here are useless for modding in case you plan to use Kailh switches. Opposed to Cherry (left) and Gateron (mid), Kailh (right) uses a different latch design, which is not compatible.

If using PCB hotswap sockets cutout #1 is probably the best option.

Just wanted to add this information, because this is somewhat of the reference post for switch plate cutouts.
« Last Edit: Sun, 08 April 2018, 08:03:11 by okaa »