Newsletter Article: Finding and Restoring Vintage Auger Bits
If you have a vintage drill brace you need some bits. The jaws of vintage drill braces are designed to accept auger drill bits a four-sided tapered shank on them. You can purchase an adapter so the brace will accept modern auger bits with hex shanks, but why? Vintage Irwin and Jennings auger bits can be found everywhere for pennies on the dollars and just need so basic clean-up to bring them back to life.
The two style auger bits that work with old braces is either an Irwin or Jennings style. You can buy brand new Jennings style bits manufactured by Fisch (A great drill bit manufacturer) tools from Austria. While spendy they are excellent bits. They can be found at Gramercy Woodworking. You can also find new Irwin style auger bits, but they are made in Brazil and I have not been impressed with their quality.
But if you are willing to expend a little elbow grease, you can restore some old Jennings or Irwin bits that will do fine for you.
What to Look For. When examining a vintage auger bit at a garage sale, flea market, or antique shop I look for four things:
1) Is the bit straight? If it is bent, I put it back. There are so many available I am not going to spend time bending one back into shape.
2) Are the starter threads in good shape? The little starter threads at the end of the bit are what bite into the wood and pull the bit into the wood. These must be in pretty good shape. If they are worn almost smooth or are in bad shape, pass it by. You can tune up these threads, but I want them to be pretty good to start out with.
3) Are the flutes on the end in good shape? I want the flutes that score the wood not be ground down more than half of their original size and I will inspect it to be sure no one tried to sharpen the outside of the flutes; only sharpen the inside of the flutes.
4) How bad is the Rust? I can clean up pretty bad rust, I just don’t want a bit that is severely pitted. Light to moderate pitting is OK but heavy pitting is not.
Restoring old bits. I have restored lots of old bits. My method differs a little if I am using had tools of power grinder. I will describe both.
By Power Grinder: When using a power grinder, I get a couple of those sandpaper flap wheels and take the bit to it. I want to be quick about it and not take off a lot of metal, just rust. Be particularly careful not to round over the sharp edges of the spiral flutes. I usually do 60 – 120 – 180 grits. I then take a small brass brush to the threads on the end.
Step 1: Clean Thoroughly. Using dish soap, water, and a scrub brush get as much of the loose dirt off as possible. If the piece is especially grimy, an overnight soak might help get some of the gunk off. Dry the bit off and immediately either oil it or immerse in vinegar or the metal will begin to rust.
Step 2: Soak Bits in Vinegar. Immerse the bits in white vinegar. I put all the metal parts in a plastic bin to soak in the vinegar anywhere from a few hours to 48 hours. Do not leave in the vinegar for much longer than that or the vinegar will begin to eat the metal as well.
Step 3: Examine Your Progress. Every few hours, take the bits out of the vinegar and examine the progress. A few wipes with a towel will let you know how much of the rust is gone.
Step 4: Protect Against Flash Rust. When you are satisfied, take the metal parts out, one by one and dry them well with paper towels. Then immediately coat with mineral oil, light petroleum oil, citrus wax cleaner, or anything that is going to stop them from beginning to "flash rust" which can happen literally within minutes of removing the tool from the vinegar.
Step 5: Scrub. Using a series of wire brushes (small toothbrush like ones) then stiff nylon brushes I start cleaning the metal. If needed, I will sand down the bit with 120 -180 grit sandpaper after the brushes.
Step 6: Polish. Take a little dab of metal polish cream and polish the metal.
Step 7: Sharpen the bit. See Rob’s video in this newsletter to learn how to sharpen
Step 8: Oil. Wipe down with your favorite oil
Here is my set after cleaning up. Good luck