Drilling the Balance Rail Holes

We’ll start by drilling the balance rail holes. If your drill press has a deep enough throat, you can use it to drill all of the holes. If not, you can make a simple hardwood drill guide and use a hand held drill. To make the drill guide, take a short piece of ¾” [19mm] thick hardwood and drill 2 holes all the way through it using your drill press set to 90 degrees. Use the same size bit that you will use to drill the balance rail holes (see below).That’s it! When drilling the 102 holes into your keyblank, push the drill bit through one of the holes in the guide, align the bit with the target on the keyboard blank, rest the guide onto the surface of the keyboard blank, and drill. The guide will keep your drill bit at 90 degrees. When one of the holes in the guide gets worn, switch to the other hole.

The balance rail pins that will go into these holes measure .096” [2.43mm] in diameter. Take a piece of scrap wood, the same species and thickness that you used for the balance rail and drill a test hole with a drill bit a few thousandths of an inch smaller (.088?){2.33mm?] You’re looking for a good, firm fit but not so tight that hammering the pin into the hole will be difficult. A complete set of numbered bits will be most useful. The holes should penetrate the balance rail at least 1/2” [12.7mm]. If your drill bit isn’t long enough (it has to go through the ¾” thick [19mm] drill bit guide, the ½” thick [12.7mm] keyboard blank, and 1/2” [12.7mm] into the balance rail) you can always re-drill them deeper after the keyboard blank is removed from the keyframe. So, drill them as deep as your bit will allow and deepen them later, if necessary. Before you drill, take an awl and make a dimple at each hole location on the keyboard blank for the drill bit. Then, after you’ve determined the proper size drill bit to use – use it! Drill out all 51 holes on the balance rail.

From time to time, these pins may be unavailable from the Instrument Workshop. As a substitute, you can use 2" long, 6D stainless steel finishing nails. These are the nails I have used. You will have to cut off the top 5/8" from the head end of the nails and file that end smooth. This is annoying and time consuming, but sometimes you have to do what you have to do.