I didn't have a gouge chisel and needed one, so I figured I might as well build one. The main issue I had was that I needed some good quality steel I could harden, but I needed it to be round. The rat tail file I used is probably a little small but good enough for use with my mini-lathe. The other option would be to hammer some flat steel into a half-round shape, but that's currently beyond my abilities.

Supplies

A large round file (aka a 'Rats Tail' file)
Drill
Grinder
Gas torch

Step 1: Cut the File

The process of making a Gouge Chisel is a bit different, you generally want this as large a diameter a file as you can find. Since the files normally taper down to the tip we're going to use the handle end as that's the thickest point.

So using a grinder cut the tapered handle off the file.

Step 2: Soften the File

As explained in my previous instructable making a turning chisel it's important to anneal the file. To do this you need to heat up the steel and let it cool slowly. I just hit it with a torch and then covered it up with the firebricks. You can also chuck it into a campfire or firepit, just try to get it glowing over the entire length.

Step 3: Drill the Gouge Hole

Mark the middle and centre punch to stop the drill from wandering. Now drill a small pilot hole, I somehow managed to go off-centre at this stage, but that's recoverable. Now drill a larger hole, you want to make this reasonably big, but still want the steel to be 2-3mm thick.

Step 4: Cut Open the Gouge

Using a grinder cut open the gouge hole and then grind the profile flat. You can also smooth off the teeth of the old file at this stage.

Step 5: Hone Out the Gouge

You can either use some sandpaper or a Dremel to hone out the inside of the gouge to remove any drill marks.

Step 6: Heat Treat the Gouge Chisel

Now using a torch or charcoal heat up the last couple of inches of the gouge chisel until it's 'cheery red' or a magnet longer sticks and quench it in some old oil. Now clean off the burnt oil with sandpaper or a wire brush, I've recently learnt that brake cleaner helps remove it as well.

Lastly, temper the steel in an oven at about 200 degrees celsius for an hour.

Step 7: Make and Attach the Handle

You can either use an old piece of broom handle or turn a new one from some wood, make sure the handle is tight on the gouge chisel, I sharpened the handle end of the chisel so it would bite in.