Marking Knife From a Dull Jigsaw Blade

Few things are worse than a dull jigsaw blade, but I always felt bad throwing them out. It seems like such a waste to toss out a piece of high speed steel because a few of the teeth have dulled out. It also doesn't make any sense to try and sharpen the teeth again, jig saw blades cost a few bucks for a five pack.

I'm not quite sure where the idea came from, but I realized that a jigsaw blade would make an excellent blade for a marking knife. To add a little style I'll be using an exotic pen blank. This is a simple, straightforward project that yields a great looking tool to use for years in the workshop.

Items needed:

Dull jigsaw blade

Pen blank

1/2" metal pipe. I used copper but any metal is fine

Epoxy

Tools:

Chisel/hand plane/ knife. Basically something to carve and shape the pen blank with

Drill and Drill Bit

Pipe cutter or hack saw

File

Hammer

Grinder or Bench Grinder

Sandpaper

Clamp the square-ish blank to your work surface and drill a few holes side by side going into the pen blank. If you carefully start rocking the drill back and forth, you can carve out a large enough space for the blade to slide into. BE CAREFUL though, as small drill blades can break very easily.

I used a file to clean out the space a little bit, but it's not necessary. Periodically check the fit by tapping the blade into place.

With the hole drilled and cleaned out, begin shaping the handle. I used a small block plane to do the majority of the work, with a utility knife to finish out some of the finer details. A little bit of sanding smoothed everything out nicely.

For be, below a certain diameter a completely round handle is difficult to hold and my hand cramps up if I'm using it quite a bit. Simply rounding the edges over somewhat makes a much more ergonomic and comfortable tool to use I think.

A 1/4" thick piece of 1/2" copper pipe makes for a great ferrule. You don't need a ferrule, but it looks nice and provides some additional strength.

Just keep carving away a little bit of material at a time until the ferrule just barely fits over the end, then hammer it on the rest of the way.

A few light passes with the plane or knife will smooth the transition between the handle and ferrule.

Mix up a small batch of two-part epoxy and smear it everywhere! Seriously, a dab into the hole, some on the surface, a bit around where the ferrule will mount, then quickly press everything into place.

A paper towel is handy for cleaning up any squeeze out

Marking knives are unique in that they're only beveled on one side. This allows you to press the knife flat against a straight edge and leave an incredibly precise cut line. It's much finer than a pencil.

Most jigsaw blades have an angled side at the end, and depending on which side of the blade you bevel, you'll have a right handed or left handed knife. No need to get fancy here, just simple grind a slight bevel on that angle and you're done.

Any finish will work. I happened to have danish oil lying around which is my go to finish for most woodworking projects. For an added bit of protection afterwards, I rubbed in a bit of furniture wax.

And that's it! You now have a tool ready for years of use in your shop.