Drill Bits for the Surveillance Technician |
Overview
With the next Horny Old Pedophiles Everywhere (HOPE) "hacker" conference coming up in a few months, we thought it would be a good time to brush up on the fine art of installing surveillance devices. One of the biggest concerns when drilling a hole in a hotel room wall is whether you're going to hit a live electrical wire or not. Just one bad move, and your entire surveillance operation could be exposed, or even worse, your technician electrocuted!
Fret not, as this project will involve the design and construction of a non-conductive drill bit which should be perfect for drilling through drywall, or at least clearing the path for a regular finishing metal drill bit.
Construction Notes & Pictures

Overview of the parts needed. The main component will be a three foot long piece of 3/16 inch inside diameter acrylic tube. Next are serveral pieces of K & S Engineering #128 (3/16 inch) and #129 (5/32 inch) round brass tubing. The brass tubing will be used to make little "collets" which will secure the Dremel bit's shank when cutting.
The Dremel bits shown here are a #952 grinding wheel and an assortment of small-diameter, 1/8 inch shank drill bits. The #64 drill bit in this set will be used for this project.
You'll also need some old 3/16 inch drill bits, half-round, triangle, and flat needle files, a high-quality tubing cutter, a deburring bit, and two-part epoxy.

Cut the acrylic tube to the length you desire. For this project, we'll be using one which is 12 inches long. Be sure to square and deburr each end of the acrylic tube.
To make the "shank" for this non-conductive drill bit, we'll be utilizing an old 3/16 inch drill bit. You'll want to clean and "rough up" the drill with a piece of steel wool, then epoxy the drill bit into one end of the acrylic tube. Be sure there is enough of the drill bit sticking out to attach the drill chuck to. You may also wish to add a little bit of sand to the epoxy so it gives a better grip against the walls of the tube when dried.

Finished view with the drill bit epoxied in. A six inch piece of the #129 brass tube was also inserted into the acrylic tube to keep it from flexing in the middle while drilling.

Cut a small piece of the #128 brass tube to fit over the Dremel bit shank. Then, using the half-round file, file a couple of notches through the brass tubing and into the shank. These will be used to solder and secure the Dremel bit shank to the new brass collets.

Finished view showing the brass tubing soldered to the Dremel bit shank. Add a bit of solder flux to the notch before soldering to help spread the solder out, and be sure to use a very high-wattage soldering iron.

Chuck up the Dremel bit (upside-down) into a drill press and use a flat file to clean and deburr the new solder joints. Then cut a piece of the #129 brass tubing the same length as the other one and see if it fits over the new brass collet you just made.

Slide the piece of #129 over the new brass shank. File in a few more notches and solder them.
You'll run into a problem with the drill bit shank. They use high-speed steel, which is very resistant to grinding and soldering. You'll have to "pinch" the brass tubing using a Vise grips to secure it around the drill's shank.
Again, chuck up the bits in a drill press and file down the shanks so they are free of any bumps or burrs.

File a few tiny notches into the finished brass collet using a triangle file. These will help secure the new bit against the acrylic tube when epoxied in. Note the sand in the epoxy on the right.


Epoxy the new bits into the acrylic tube as shown. The #952 Dremel grinding stone was tapered down using a cleaning stone to better match the diameter of the acrylic tubing.
Clean off any excess epoxy around the bit and tube junction.

The main problem with using Dremel grinding bits to drill into drywall is that they will clump up with plaster dust. Use a cleaning stone to keep the end of the bit clean. You can even use the cleaning stone to create more of a "drill point" to the end of the grinding bit.

Overview of the finished bits. Shank is on the left, drilling end in on the right.
The top bit has no metallic pieces exposed so if it should strike a live voltage conductor, it shouldn't spark or short the lines.
The bottom bit is equipped with a #64 drill to finish off the final microphone hole.
Both bits can then be placed inside another acrylic tube to help center them when drilling.
The epoxied shank and bit are fairly secure and should handle drilling drywall or thin paneling without spinning free. These aren't really meant to drill into thick or dense materials.