Improvised (and Darned Near Perfect) Dovetail Chisel

Whenever I have a metalworking file that gets to the end of its usefulness, whether for sharpening saws or just shaping metal over at the fabrication bench, and regardless of the cause of its infirmity — is it worn out or just boogered up? — I never discard the old tool.  It is almost always a great source of very hard tool steel so it goes into my scrap inventory for me to make something out of later.

This habit and experience served me exceedingly well recently when we were up visiting L’il T (and his parents, of course).  I carved out a little work station in their garage and just invent projects to occupy my time when I am not puttering around with house chores.  Well, this trip I was making a tray for the traveling tool kit I bring with me.   Much to my aggravation I realized at a particular point that I had not brought a dovetailing chisel for the small dovetails I was cutting into the ~5/16″ cypress stock I was using.  My first attempt to chop the dovetails with my 1/4″ bench chisel did not yield a satisfactory result.

Since I am not at home on these trips I make a frequent, almost daily, pilgrimage to their local excellent hardware store.  I set the project aside and figured I would see if the hardware store had a decent rack of steel bar stock I could use to make myself one of the triangular dovetailing chisels I like so much for small work.  I have made several and find them indispensable for making tight petite dovetails.  Although the hardware store did not have any bar stock that struck my fancy, I noticed their file rack nearby, and that they had a triangular file that would certainly fit the bill for about $7.


I brought the file home and set to work on it.  Yes, it probably was a travesty to use a brand new file, but that’s all I had access to.  My first task, undocumented alas, was to fashion a tapered octagon handle from some cherry in my scrap stash.  I drilled and then drove the file tang into the handle.  A little too vigorously, as it turned out.  At some point soon I will fit the handle with a bronze ferrule, but I have not got there just yet.

Using a Dremel tool with a cut-off wheel I chopped the file roughly in half.

It was time to reach for my new-ish extra coarse diamond stone and get busy grinding off the file teeth and creating the bevel.  This is exactly the kind of task this tool was created to accomplish, which it did surprisingly fast.

Once the coarse diamond stone had done its work I switched to the finer combination diamond to bring the surface to the place where it took only a few strokes on the 10,000 grit water stone to bring the bevel and the back to perfection.

In battle the new soldier performed with valor.  You can see the blow out on one of the dovetail shoulders resulting from using the 1/4″ bench chisel.  The rest of the joint shoulders were fashioned with the new tool, which is rapidly becoming one of my favorites.  The fact that I fabricated it myself by re-purposing something extant only enhances my affection for it.

1/4″ bench chisel vs. the new tool