Hi Betty, good idea, but you have to be very careful or the bur can catch and run across the surface of the piece. You can dig a pretty sizable hole where you don’t want one in a split second. This is true whenever using the side of a bur to do any sort of cutting on an any surface that doesn’t have something on the other side to keep it from wandering. Krause burs are especially prone to running away and digging a trough.
The ratcheting is caused by using the bur to cut the entire diameter of the seat at one time. Eliminate that, and you won’t get the ratcheting. Ted is right, it is a resonant noise caused by the bur bouncing around the hole, cutting deeply in one spot and bouncing around to the next notch and then repeating the process multiple times per revolution. That buzz you hear is caused by each flute bouncing from notch to notch multiple times per second
The ratcheting can be reduced by using a much lighter pressure when cutting and holding the tool and the work as solidly as possible so they aren’t able to move with relation to each other. It happens more frequently with finer burs as opposed to coarser high-speed burs. The more material being cut away the more the tendency to ratchet, i.e. the smaller the pilot hole the more the bur cutting the seat will have a tendency to ratchet. Once it gets started, it can be really hard to get a smooth seat again.
If you use a smaller bur and cut the sides of the seat a little at a time and work your way around the seat as opposed to cutting the entire diameter in one motion, you won’t get the ratcheting. You can also do the same thing to smooth it out once it happens. In ether case, you have to be careful you don’t over-bur the seat. That’s where a girdle stretcher would come in real handy.