According to Greek mythology, every time you cut off one of the Lernaean Hydra's multiple heads two grow back to replace it. Now, with some spare bits and some creative grinding, your lathe tool can do the same thing! In this case, having multiple heads means you won't have to throw out an entire tool because of broken pieces, constantly dull edges or catastrophic failure. Just find another paddle bit, drill bit, or other metallic bit to shape a new head and you're back in business.
If you've ever gone shopping for wood turning tools for your lathe you've probably noticed they can be really expensive. I wanted to find a way to make tools that would be durable and stay sharp without costing a fortune. Enter the Hydra. The real savings come because instead of having to buy a whole set of tools, you can just make the heads and a single base out of inexpensive spare parts.
Dowel or other piece of turnable wood
Hex Bolt 3/4" x 8"
1" copper pipe cap
Allen head screws
Assorted paddle bits, drill bits, or the like
Sixty second epoxy
Step 1: Make the Handle
If you are making this tool because you don't have any turning tools yet, you can leave the dowel as is or cut it down to the size you would like with a saw. If you have some turning tools and just want to supplement your collection and/or use up some spare paddle and drill bits, you can turn the handle to make it look nicer.
I didn't measure the dowel before I cut it. Instead, I held it in my fist and cut it an inch below where it met my elbow so I could grip it between my elbow and waist when using it. You can make yours whatever size is comfortable for you to use on your lathe.
You will need to cut a shoulder into the top of the handle that the copper cap will fit over. Measure the dowel using a crescent wrench to double check the diameter. The height of the shoulder should also match the height of the cap.
Step 2: Prepare the Hex Bolt and Copper Cap
The hex bolt will act as the shaft you put the interchangeable heads into. Cut off the hex head with a hack saw so you have a long shaft with threads on the end.
After you cut off the head, drill a hole through the non-threaded end of the bolt. I went down about an inch and a half.
You will also need a hole in the copper cap for the bolt to go through into the handle. Use a step bit to cut a hole the diameter of the bolt. Try to center the hole, but if you are a little off it doesn't really matter because you will cut the handle to match.
Step 3: Make Holes for Your Allen Head Screws
Use your drill press to drill two holes in the bolt for Allen head screws. Use a drill press vice to hold the bolt in place while you drill. Usually the drill bit you use will need to be slightly smaller in diameter than the screws. Follow the directions on your tap set. Drill two holes. Try to line these up so they will look nice and hold the bit in place. Mine are offset a little, but they hold the bit just fine.
Once you have your holes drilled, use your tap set to thread the holes.
Finally, use your Dremel to round and smooth the edge.
Step 4: Put Together the Tool Base
Once your hex bolt and copper cap are prepped you are ready to put together the base for your tool. Fit the cap over the shoulder in your handle. Mine was tight enough that I pounded it on and it was snug. You may want to add some glue to help hold it together.
Use a paddle bit the size of your hex bolt to drill a hole into the wood to match the hole in the copper cap. Drill down about two inches, or enough to cover the threads in the hex bolt.
Coat the threaded end of the hex bolt in 60 second epoxy and slide it into the handle. Allow to dry completely.
Step 5: Shape the Paddle Bits
At this point you will want to shape your spare bits into the lathe tools you want to turn them into. I took a paddle bit that I've never actually used before (who uses 11/16ths?) and cut it diagonally to make a skew. I sharpened it using a Dremel tool. I used other bits to make a parting tool and a round nose chisel.
You will also want to use your Dremel tool to flatten out one edge of each bit for the screws to sit against when you insert the head into the base.
Step 6: Shape the Nut Driver or Drill Bit Into a Gouge
I had a nut driver that was the right shape to make a gouge, but you could also use a drill bit. Use a Dremel to grind down the nut driver until you are left with a u-shape. Then sharpen the edge using the Dremel. You can use different size bits to make different gouges, just make sure the other end is the right size to go in your shaft.
Step 7: Assemble Your Tool
Once you have your bits ready you are ready to assemble your tool and start turning. Make sure you tighten the Allen head screws firmly each time you change the head to ensure stability.
I used my new tools to turn a handle for the rod I use to knock the spur bit out of the lathe. The tool felt solid and the bits worked well.
And you're finished! My favorite part of the Hydra is that as long as you can cut and grind bits there will almost never be a need to buy specialized turning tools. If you've never known the pain of having to spend way too much money on a tool you can use for exactly one bizarre project, count yourself lucky. Then build this tool and avoid the pain forever.