Now lightly tap it in place to registers its position. Often the punch will stay put when you remove your hand – if not it is easy to relocate.
Now, using a bit that is 3/64″ under the size of the square hole (3/8″ square hole – use 21/64″ bit), drill out the center. Use an ordinary twist bit for this and not a brad point. The leading sharp corners of the brad bit will catch on the inside of the chisel and damage themselves.
As a furnituremaker, working in the style of Greene & Greene, I have chopped out more than a few square holes for ebony plugs. The accepted method for this has been to drill a round hole and use the chisel from a hollow chisel mortiser (hand held) to square up the holes. This has worked to some degree, but with limitations. One of those limitations being that a 3/16” hollow chisel was not available. Since I employ quite a few 3/16” square ebony plugs in my designs, this meant chopping out those holes by hand, with a lot of patience (and time).
This prompted me to design my own hollow square punch – not only because I needed a 3/16” size, but also one that is specifically designed to be hand held.
My early attempts did not meet expectations, but after a few tries, the new tool was actually outperforming expectations. Dozens of these were machined and made for me, by my friend Bob Hadley. Thanks BOB!
Once I had a working tool in hand, I submitted the idea to Lee Valley Tools. They liked it and turned it over to their R&D department. The Lee Valley folks made improvements and sent me the prototypes for testing. My friend George Knutson helped me run the punches through their paces. I then returned them along with comments and suggestions. We went through this process twice. I was greatly impressed with the Lee Valley R&D people – they really brought the tool to perfection!
Later this month Lee Valley Tools will have available for purchase the hollow square punches in six sizes -3/16” – ¼” – 5/16” – 3/8” 7/16” – ½”.
Use the product code 50K5920 to check on the punches availability.
I will follow up soon with a blog that details the use of the punches.