The goal of this project was to help me relearn how to use the metal lathe and create a useful project. Basic lathe operations were used to create the scratch awl. The case and handle are made from brass and the point is made from tool steel. After making the point I hardened it and then heat treated it. I will include three youtube videos showing how I made each part.
Step 1: Gather Your Materials and Tools
You can use either 1/2" round or hexagonal brass rod approximately 6" long
3/8" O-1 tool steel approximately 5" long
Metal lathe w/ 3 jaw chuck
3/8"-16 tap and die
3/16" & 5/16" drill bits
Torch (Propane, MAPP, Oxy Acetylene)
Oven - toaster oven works fine
Step 2: Create the Handle
The first step in creating the scratch awl is making the handle. Cut a piece of brass 2.25" long. This can be either 1/2" round or hexagonal stock.
Place the stock in the 3 jaw chuck and center drill. I like to center drill the end first so when I face the end of it, if my cutter isn't exactly on center, I don't end up with a nub in the center.
Turn the last .25" to .375" diameter. Use a 3/8"-16 die to cut threads on the end. Undercut the threads with a parting tool so that they will fit well in the case.
Drill a 3/16" hole in the end of the handle .5" deep
Reverse the stock in the chuck and face the end. Use a file to round over the end of the handle.
Sand the handle to the desired shine. I sanded through 800 grit and then used synthetic steel wool on it.
Step 3: Handle Video
Step 4: Make the Point
I start by annealing the O-1 tool steel with a torch. I heat the rod to red hot and allow it to slowly cool.
Chuck the steel in the three jaw chuck and turn it to .031"
Set the compound rest to 4 degrees and make sure the cutter is directly on the center of the work piece.
Start on the end that is going to be the point and start taking light cuts. Slowly work your way back taking longer and longer cuts. I keep a small bit of metal at the point to support that end.
Use a file to touch up the taper and then sand to desired sheen.
Step 5: Making the Point Video
Step 6: Heat Treat the Point
Once you have made the point, you should heat treat it.
Fill a tin can (or any other fire safe container) about half way with vegetable oil
Use the torch to heat approximately half way up the point end to red hot. Hold it at the temp for a little bit to ensure it is well heated.
Once it is red hot, plunge it into the oil and swish it up and down a bit until it cools.
The tip is now very hard (a file should skate across it) But also very brittle.
In order to make the point usable it must be tempered.
I use my toaster oven to temper with. If you use veggie oil harden the point there should not be any smell when you temper so your significant other shouldn't yell at you too much for cooking a scratch awl point where they make toast.
Set the toaster oven (a real oven works too) to 400 degrees and leave the point in for an hour. Turn the oven off and let it cool. Tempering is done.
I rechuck the point in the lathe and resand to clean it up
Step 7: Make the Case
Cut a piece of brass to 3.75"
Chuck it in the three jaw chuck
Center drill and face the end
Drill a pilot hole - used the 3/16" bit I already had in the chuck
Drill a 5/16" hole 3.3" deep
Use a 3/8"-16 tap to thread the first .5" of the case
Chamfer the hole slightly
Check the fit of the handle
IF USING HEX STOCK
If the faces of the hex bar don't align when the handle is screwed in - take VERY LIGHT facing cuts on the case until the flats line up
Once you are happy with the fit, flip the stock over and round over the other end with a file.
Sand to the desired sheen
Step 8: Making the Case Video
Step 9: Putting It All Together
After checking all of the parts for fit, JB Weld the point into the handle. You could also solder it or use some other type of adhesive.
If desired, buff the entire project on the buffing wheel
Put scratch awl in your pocket, it won't poke you, and use as needed.