Introduction: Secret C-Clamp

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.


1 C-clamp
Electric Drill or Drill Press
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.

Secret Compartment Challenge

Participated in the
Secret Compartment Challenge