Step 1: Parts and Tools
This camera is a typical Quickcam. It has a little attachment on the bottom that snaps into a base - it does not clip onto anything, and the base is about 3 cm high. It isn't shown here because I have no idea where it is.
I got a coupling nut that is threaded for 1/4 inch-20, which is the standard size for a tripod attachment, and is an inch long. I also got a 1/4 inch-20 screw that will fit into it, and it is 3/4 inches in length. The screw is a countersunk machine screw, and I got a countersunk one because I figured that space is a premium inside the webcam and I could use this type of screw without the head protruding into the body of the 'cam.
To open up my webcam, I needed a Phillips-head jeweller's screwdriver, and I needed a drill with a 1/4 inch bit and a larger bit (or a countersink bit) to drill the hole for the screw. I also needed a vise. I used Loctite on the screw threads. A large screwdriver and wrench were needed.
Step 2: Disassemble the Webcam
Use a tiny Phillips-head screwdriver to remove the screw and carefully separate the two halves of the case.
The "guts" of this camera are held in place just by the case halves, so once the case is apart, you can just pluck the insides out, leaving the bare case. It's not actually necessary to take out the circuit boards and buttons and stuff in my camera. Take a moment to see where everything goes before removing parts (you might even want to take a quick picture before, so you can see how it goes back later).
Remove the little part that snaps onto the base - this is the bit we need to work on. If your webcam is configured differently, you may need to drill a hole in the case instead of the base attachment like I did.
Step 3: Drill Out the Camera Base Support
I'll refer to that little black thing that snaps into the base as the camera support from now on. This part needs to be drilled out with a 1/4-inch bit to accept the machine screw. In order to have the camera balanced and level on the tripod when you are done, the hole needs to be centered well and straight up-and-down. Therefore, make sure the support is clamped securely and level in a vise, and take your time drilling. A drill-press would be ideal for this, but it's not necessary if you're careful.
After I drilled the hole, I countersunk it to accept the screw. You can do this if you have a larger drill bit handy, but I happened to have a countersinking bit for my drill to ream it out.
Step 4: Reassemble Your Camera
Apply Loctite to the threads of the machine screw, and then insert it through the camera support and screw it into the coupling nut. Don't tighten the screw very much, as it will deform the camera support part and it won't fit back together. We will be relying on the Loctite to hold the nut in place, not the tightness of the screw.
Place the camera's optical sensor and main circuit board in the case, making sure that the camera's focus ring is inserted correctly and the circuit board is seated properly in the case.
Install the button and mike into the top of the case. For this cam, there was a little light pipe that needed to be correctly placed in relation to the main circuit board.
Place the modified camera support into the case.
Button up the case with the tiny Phillips-head screw.
Step 5: Mount Webcam Onto Your Tripod
I am using a little mini-tripod here, and this is a bit top-heavy since the coupler nut adds an inch to its height which raises its center of gravity. For a larger tripod, of course, this will not be noticeable.
This mod can work with other cameras too, but for some you may need to drill a hold in the camera case instead of the little camera support bung. If the plastic of the case is thin, use a regular pan-head screw.
In the case of a webcam with a clip, you could just clip it onto a coupling nut and screw that onto the tripod - no need to drill anything, and the coupling nut is plenty big enough for the clip to grab onto.