I made a replacement sight elevator for an air rifle the other day. It required me to undercut a groove in a tiny piece of plastic (1/4″x1/4″x1/2″). I found that I had some micro keyseat cutters (marked “Richards”) and gave them a try. Normally keyseat cutters are used to cut semicircular woodruff keyseats but they work okay for tee slotting and other slotting jobs.
Sorry for the picture quality — shiny metal and black plastic is a bit difficult to photograph. The tee slot cutting went well. I had to take small cuts as the plastic really wants to come out of the vise.
The finished part.
Two of the cutters I have. As I said they are marked “Richards”, which I presume means Richards Micro-tool but I was unable to find them in their catalog. I did find two suppliers of Carbide ones, Harvey Tool and Whitney Tool, although they are a tad expensive. I could have probably used a Dremel 198 cutter as well.
In any case, I thought it would be worth mentioning this type of cutter as it was certainly a problem solver for this project.