Simple $15.20 upgrade to my electronic chessboard

12x1mm, yeah? I have enough of those lying around from another project to start right now! Nice. Thanks for the info.

@RoaringForkChessClocks

Here are some tips for the Vonset / Femuey L6 board. You will want to get Neodymium magnets that are 10mm in diameter and 1.5mm thick. Do NOT get any magnet smaller than 10mm dia. because it will 'repel' the center of that square. 12mm is the original size and works well too, but I noticed a slight numb centering effect. The 10mm dia seems to be the perfect match to the metal size under the squares. Also, I had ordered 10x2mm for the larger pieces and 8x1mm magnets for the pawns from Amazon but received actual sizes of 10x1.6mm and 8x0.8mm magnets. The 8mm magnets would repel from the center, so I ended up using 10x1.6mm magnets for all of my pieces. As for the thickness, the 1.6mm worked very well for my 2.4in king set (see my earlier pictures) and I can easily play with the board held vertically.

For installation, I ended up using nylon washers to frame the magnets on the bottom and this worked out very well. You will need to check the diameter of your pieces, but for me I used M10 20mm OD for my larger pieces and M10 16mm OD for my pawns. Black nylon looks good. This method was way easier than trying to drill into the pieces to insert the magnets. Then I just put the thin felt back on the bottom.

Regarding magnet polarity, make sure that all of your magnets are installed in the same direction (i.e. north all pointing down). The board doesn't seem to care (and the original pieces had all the pawns opposite from the rest), but sometimes the pieces could slide towards the adjacent pieces if they were not in the same direction.

Another note, don't get magnets any thicker than 2mm since too strong of a magnet can unintentionally activate an adjacent square when moving pieces.

This is gold, @Yenster1, thank you! With the pieces, the 12x1mm were going to fit fine, but it was going to be tight with the pawns. Even going slowly I was worried about blowout or full splitting while drilling the detents since I have no idea how old these pieces are or what kind of wood they are. 10mm will be a much easier job all the way around. The tip about the washers is something I hadn't even considered for centering; that's smart work. Thanks again, and I'll make sure to update with progress and completion pics.

@RoaringForkChessClocks Here's what my pieces look like.

I don't even notice the slightly raised bottoms. They feel good with the felt (the original pieces are just exposed plastic and metal magnet).

Oh, I highly recommend using some kind of putty adhesive to stick the magnets and washers to the pieces. I used some Bostik Blu-Tack from my tool box (that's about 10 years old) and it worked great. It sticks to wood, plastic, and metal. It fills into imperfect surfaces/crevices. And it's removable if you want a do-over.

[concept falls into place with a dull thud] Wait. So you didn't drill out your pieces at all then, didja, with the washers as the seat for the magnets? I'm not even gonna lament the nearly half-hour I spent in OnShape knockin' up a multi-piece drilling jig -- that's gonna be a huge time-saver and my worries about the pieces coming apart in the drill press no longer matter. Sweet! Dunno why that wasn't clicking in my head. After pulling the felt on my pieces, several of them are pretty uneven and will need just a little sanding to fair them, but going with magnet-in-washer on the bottom? I'm with you: ~2mm proud (esp. with a little more weight) is something that I'll only notice as an improvement.

The board and the magnets won't be here until late next week (Amazon Prime is 6-8 days where I live), but it looks like I'll be able to get this working the same day. Thanks again for the info, neighbor!

@RoaringForkChessClocks

Right...no drilling, no grinding, no sanding, less risky, less tools, much faster and easier, no permanent damage, and adapts well to imperfect surfaces (like bottoms of old wooden pieces).

I was fortunate to have some Bostik Blu-Tack handy to test out (and develop) my method.

1) gently pull off the felt.

2) press a magnet to the bottom of the king (largest piece) using a very small amount of the Blu-tack.

3) test the king on the board to see if it will work (mine worked fine with 10x1.6mm magnets)

4) press a nylon washer to the bottom around that magnet using a very small amount of the Blu-tack until it was flush with the magnet.

5) stick that felt back to the bottom...Done.

Note that the Blu-tack will fill into any rough/uneven surface.

You had made a remark about the added weight...just want to make sure you're NOT considering metal washers...but use nylon washers like I did. I suspect metal washers would interfere with the magnetic flux.

Also, I got 1mm thick washers for my 1.6mm magnets. Don't get the 2mm thick washers unless you will actually get 2mm thick magnets (that are actually 2mm thick).

Hey can you post a picture of your chess pieces?

On the construction notes, no, definitely not metal washers. Since the range of measurements for bulk neodymiums can very widely, as you know, I'm holding off on getting the washers until I can actually measure what arrives, but if I can't find the right sizes of washers to match locally (I'm enough into the boonies that selection can be a bit limited for just about anything), I can just print 'em. The felt that's on the pieces now is really patchy on the pieces that still have it, so that'll be replaced no matter what. The bottoms of the pieces aren't bad under the felt, just cupping and glue or varnish drips, nothing a few quick passes on the sander won't fix just to get 'em flat. I'll likely use the same Ecoweld contact cement I use for other stuff since I know how it behaves (repositionable for quite a while, but then bonds hard if you leave it). But golly is it gonna be nice to not have to go thru with drilling detents for the magnets; so much less work and worry!

31mm squares, box is barely holding together. I was thinking of tossing the box, but hey, some yellow glue will fix it up, so why not keep it?

Definitely not bad for two bucks.

@RoaringForkChessClocks Not bad indeed. Small wooden pieces with detail and character. I look at that set and can't help wondering where it came from, and who used them over the years. Great find! Definitely worth reviving those pieces back to regular use.

This set works perfectly with my Risc 2500. I did replace the bottom paper with 5/8 x 1mm felt.

I no longer have to use the edge of the pieces. A slight down press activates the squares.

A real pleasure to play with.

@RoaringForkChessClocks Hey did you adapt those pieces to the L6 computer game? If so, I'd like to see a picture of how it turned out.

Not yet, sadly. Y'know when life comes at ya fast, not bad or anything, just all of a sudden you are busier than you are aware, and you look up and weeks or months have gone by? That. I'm hoping this weekend for prepping the pieces; we'll see how the week goes.

Dang. I just looked at the shelf where I put the computer, pieces, magnets, and washers, and realized I never even took the plastic wrap off the computer. How is it December already?!

@RoaringForkChessClocks Well no hurry. With the custom pieces, I've had a lot of fun with this computer chess game and play it pretty much every day. The AI really feels more human than my older board. One seemingly hidden feature that I discovered is being able to force change the black's opening by hitting the 'hint' button a few times right before your first move. I also really like that I can just walk away from a game and later just turn it back on and pick up right where I left off. Anyway, I hope your pieces turn out to be a good fit.