Diamond Jig and instructions for the inlay The dimensions I give for the jigs may need to be altered to fit your tool(s). Common denominators You have to start with square stock. I’ll assume that you purchased square stock of sufficient size to turn your grip or that you have cut a larger piece into a suitable rough square. Your first step is to run it through a jointer to flatten one side and square it to another. It may take a few passes and when done, mark this side and place it against the 90° fence and flatten the side you squared to. Mark this side also. Next run all your pieces through a thickness planer making sure that the sides you jointed and marked are opposite the knives. If you don’t have these tools go to a cabinet shop and see if they will do this for you. Your stock has to be square and uniform in thickness or your final results will be less than desirable. I start with 1 1/2 ” rough square stock and will end up with 1 1/4 ” or 1 3/8” finished stock. The next important component is that your jigs must have a flat bed. Plywood will work; choose your piece carefully. A better material is MDF, medium density fiberboard; best would be solid surface counter top material. All of these materials should be available at a lumberyard or from a contractor and can easily be worked with common wood working tools. If you can come up with the solid surface material great! If not you will need some hard wood to make runners out of. You won’t need a lot of this so see if you can come up with some scraps somewhere. I’ll give guideline dimensions later. Since I’m sure someone will ask, I use Tightbond II for glue most of the time. If I know I have the time to wait I’ll use rod bond to glue the inserts and handle pieces. Tightbond’s set time is much shorter and I’m impatient. Lastly, spend some time making absolutely sure that the table on your saw is 90° to the blade. If this is off, the pieces won’t fit together nicely. The jig
I built mine out of 2 pieces of scrap 3/4 “ MDF glued together. It is 18” long X 2 1/2 ” wide. Cut the 45° angles in the center of the block. Next cut a square piece that fits the 45° angles. Cut this in two pieces, depending on the size of your drill press table. The idea is that the cut will be so that the 2 pieces will serve as stops and clamps as you cut the mortises. On one piece you want to leave the full square on 1 end about 1/2 “ long. On the rest of this piece and the other piece you’ll cut it from corner to corner, providing the flat clamping surface. On the piece that you cut completely flat, you’ll want to add a strip to the top that will act as a fence to center the mortise so that you won’t have to move the fence again. It’ll probably take some fiddling to get this sized.
Making the insert You set the jig up so that it is right under the corners of the chisel, which is set 45° from parallel to the jig. Clamp a fence behind the jig and clamp the jig to the fence. You’ll probably find that a 1/4 ” diamond looks best. From corner to corner this measures 3/8” so double that to determine the length of the block you’ll cut to drill these holes. Bore the hole in this piece for the mandrel first. You will mortise only ½ way through to prevent blow out. Set this block in 45° part of the jig and position the jig centered under the bit and clamp the 2 top pieces down. Now simply cut the mortise, flip the stock and repeat. To cut the mortises in the flat sides of the block, set the block on top of the lat part of the jig centered on the mortising bit. Clamp the two ends of the jig down and mortise out the flat sides. Picture All the mortises are made at this point. Cut some 1/4 ” pieces out of the contrasting wood that you have chosen. You’ll want the length to be about 1/2 of the width of your stock. Put some glue in the mortise and drive the square accent into the block. http://classiccustomwood.com/ 712-580-2666