it is quite simple to make a set youself, I did using thin wall stainless tubing, in both square and round. I used 6" lengths of the various sizes and used a cinical grinding bit on adrill to sharpen them, I found metal caps to go over the ends where I use a small wooden mallet if needed, they work well in balsa and liteply. I make a new one if I need a different size, and have most sizes in round up to 1 1/4", and square up to 3/4". very useful, and easy to sharpen if needed. One point to remember is to sharpen from the inside, That way youget clean straight sided holes that should fit snugly. I even made the mallet myself using a small piece of 2" wooden cutain rod and 3/4" dowel