The next thing I did was mount the braces. Prior to starting on this design, I half-built a kingpin based keyboard. In order to use the back-of-hand and thumb-joint braces from the unfinshed kingpin keyboard unchanged, I decided to just screw them to the end of my block of wood. If you're making new braces and/or using a thinner block, you might be better off attaching them to the underside of the block or something. This would obviously require slightly differently shaped braces.

I had intended to use a spring washer and at least one flat washer, but first I just whacked the braces on to give it a go. This worked out better than expected so I've just left it without the washers. Your mileage may vary.

My over-length block of wood prevented me from using my existing heel-of-the-palm brace directly, and I was never really happy with it anyway, so I started again from scratch. In order to keep the keyboard adjustable, I decided to mount this brace on it's own piece of deck track. The deck track is intended to be used as-is in the lengths it comes in, so they only give you two nuts and two bolts per length (one for each end). I had used these to mount my keyswitch-mounting tracks, and as I mentioned before, the heads of the small woodscrews I had on hand wouldn't fit between the lips of the deck track. Since this piece of deck track doesn't need to cover the entire width of the mounting block, I just made the track a little longer than the required usable length, then reamed out a space for the head of my mounting screw at each end. Alternatively, I suppose you could cut away the entire upper section of the track at the ends, leaving just the part that you want to put the screw through.

I only used a single piece of deck track this time and I haven't had a problem with the rotating effect I was worried about for the keyswitch mountings. However, the keyswitch mounts are lighter gauge, smoother wire, so I'm not convinced that one track is enough for them (I should probably also mention that a second track offers more support to the mountings). My new brace is just a bent piece of coat-hanger wire (it's not actually from a coat-hanger, but more on that later) with rubber tubing where it touches my skin and a hook on the end to bolt to the deck track. This brace lies along the edge of my palm and it in contact with my skin along most of its length. If you want one that just touches your palm in two spots (one end supporting the end of the mounting block and one end braced against the heel of your hand), then you'll have to do some more creative bending, use two braces, and/or mount your brace(s) differently.

This is the best photo I have showing the heel-of-palm brace and its mounting. At the top end of the track you can see where I reamed out the lips of the track to make room for the head of the screw (you can make out the bottom one too, but the top one is clearer).
It would be better if the rubber tubing went up towards the hook a little way. As it is now, that end is kind of scratchy against my skin, so I'll probably put a new piece of tubing on (or make a whole new brace) when I get around to it.

On a largely unrelated point, but worthy of note here, is the rubber stopper on my thumb-joint brace. Mr. McKown's design calls for a wine-bottle cork, but I didn't have any handy and I did have this rubber stopper lying around (I wanted one for another project some time ago and they only come in packs of four). There's nothing special about it, so just use a piece of cork if you've got one.

There are a few of other things worth mentioning about the deck track mounting: the nut, the bolt and the wire hook. First, the nut. For the deck track system to work effectively, the nut has to be a very specific size: small enough to fit in the track and slide back and forth, but big enough that it can't spin freely inside the track (because the track must act as your spanner when tightening the bolt). As far as I can tell, this track is supposed to be designed for metric size M3.5 (ie. 3.5mm) nuts and bolts. Unfortunately, I couldn't find any local supplier that stocks this size. The closest imperial size is 1/8 inch, and 1/8 inch nuts and bolts are widely available almost anywhere. It turns out that not all 1/8 inch nuts are created equal. It took me quite a while to find nuts with the right fit, but find them I did.

This photo shows the brand and type of nuts and bolts that I'm using (as well as the washers, since there was room in the photo). The nuts and bolts came packaged together. Note that not just any Zenith 1/8 inch nuts will do. The shop I looked in right before finding these also stocked Zenith brand nuts and bolts, but those nuts were too small. For anyone else out there from Australia, I got these at my local Magnet Mart, but there's no guarantee that your nearest Magnet Mart stocks the same ones.

Now on to the bolt. These 12mm (half inch) bolts were the shortest 1/8 inch bolts I could find locally, but they're still too long for bolting thin items (ie. a spring washer, two flat washers and a piece of wire) to the deck track. From memory, I needed to make them about 4mm shorter for the keyswitch mountings and 2 or 3mm shorter for the heel-of-palm brace. A couple of things worked in my favour here: there is a few mm of clearance available under the nut before you hit the bottom of the deck track, so the exact length of the bolts is not critical, and I have a little experience hacksawing bolts down to shorter lengths. If you have your own method for shortening bolts, then you are of course free to use that method (far be it from me to teach my betters to suck eggs). For those that could use some help, I will explain a few tricks I have learnt that I find helpful when sawing the threaded end off bolts. First, put a nut on the bolt before you start, and do it up far enough that it will be on the part of the thread that you are keeping after the cut. The reason for this is that undoing this nut AFTER cutting can help to straighten out any damage done to the thread by sawing. If possible, use a saw blade that fits into the groove of the thread you are cutting. That will probably be difficult here as the thread is fairly fine, but you can still try to let the saw be guided by the thread. Put the end of the thread that you are cutting off into a steel vice and do it up tight. It doesn't matter if the vice crushes the thread because we're throwing that piece away anyway. Finally, hold on to the other end of the bolt while you're cutting and try to keep it straight, especially when you get near the end and it wants to bend. This will limit the damage the saw does to the thread and minimise the size of the inevitable "hang-nail" bit that breaks off at the end. Be warned though that both pieces of the bolt will get hot due to the friction of the saw, and you can get a little burn before you know it if you hold the bolt in your bare fingers. Best to use pliers or wear gloves if you're inexperienced at this. If you have a small pair of wire cutters (such as those used for hobby electronics), then you might want to snip off that hang-nail piece sometimes, but only if you can get the cutting edge of the cutters neatly into the groove of the thread.

And finally, we come to the wire hook. I used 2mm thick wire for my keyboard (for reasons explained later). This is slightly lighter gauge than any of the coat-hangers around here, but I still had to really force it to get it to bend enough to make a hook narrow enough for the 1/8 inch bolt and washers. If your coat-hanger wire cannot be bent into a tight enough hook (and it's not just a matter of brute strength -- the wire may break before bending far enough) then you may need to find some lighter gauge wire for your heel brace. This issue will come up again with the keyswitches, where using a lighter gauge wire may not be an option since it won't fit your switches. In that case you can use larger (but obviously heavier) bolts and washers. Alternatively, if you have a blowtorch, you could try heating your wire to make it more flexible. This will of course also make it more difficult to handle without gloves.