Can an ordinary c-clamp have a secret compartment? Absolutely. Can it have 2 secret compartments? Let's find out. This project is fairly simple but does require some basic metal working skills. I will be using a metal lathe but fear not, this project can be made without one. (I know because I've done it) Plus when you're finished, the c-clamp can still function properly.

Supplies

1 C-clamp
Hacksaw
Electric Drill or Drill Press
Vise
7/32 Drillbit
Metal file
1 Tap and 1 Die (1/4-28)

Optional - a metal lathe if you have access to one

Step 1: Cutting the Handle

Use a hacksaw and cut off one ball at the end of the handle. Clamp in a vise or even use a vise-grip. Make the cut about 5/16 inch beyond the ball. This allows for cutting 1/4-28 threads.

Step 2: Drilling the Handle Shaft

I drilled the shaft on a metal lathe but if you don't have one, clamp the handle securely in a vise. File the end flat. Use a hand drill or drill press. Use a center punch to mark your starting point. Now drill a 7/32 inch hole about an inch deep. You can always deepen the hole latter if you need more depth.

Step 3: Threading the Handle Ball

This is probably the hardest step but still not too difficult. I Machined the shaft down to a 1/4 inch diameter and filed the end at an angle to help start the threads. No lathe, no problem. Clamp the ball in a vise and hand file the diameter of the shaft down to a 1/4 inch. Or, chuck the ball in your drill press and while spinning, use a file to reduce the diameter to 1/4 inch. Use a 1/4-28 die and thread to the ball. Reverse the die and re-thread to the ball again. This will ensure deep threads the full length. So, although this was machined on a lathe, it can be done in a vise and drill press.

Step 4: Threading the Handle Shaft

Use a 1/4-28 tap and thread about 3/8 inch deep. This is one of the easiest steps.

Step 5: Counter Sinking the Handle Shaft

Countersink the shaft handle about 1/32 inch deep with a 1/4 drill bit. This will allow the ball to sit flush on the shaft when screwed on.

Step 6: A Finished Secret C-Clamp

Now you have a finished secret C-Clamp. The handle can even be removed and slipped into your pocket for a portable secret tube. The larger the clamp, the easier it is to machine. If you have the patience, smaller clamps can be used but will be a little more difficult (smaller drill bits and taps) but can still be fun!

Step 7: Secret C-Clamp Update

A fellow member, "Pernickety Jon", had a great suggestion (challenge). Thanks to Jon, the Secret C-Clamp now has 2 secret compartments. Fairly basic machining. Cut the acme rod with a hacksaw or bandsaw. Bore out a 3 inch deep hole on the long piece. Bore a shallow hole on the short piece. Tap for 3/8-16 threads on each piece. Install a 3/8-16 set screw on the short piece. Done! I simplified this a bit but it's fairly easy. CAUTION by machining any threaded rod, the leading thread edge is razor sharp. Take care and have fun.