Jonathan,
You touch the edge of the bit only when starting the cut. The bit will move away from the plate as it cuts at the angle. It is important to make the cut as representative of the bit shape as possible as any widening of the Groove will diminish its effect. As far as the phrase concerning making your cuts to the left of your primary cut, I was describing the normal process of making the cleaning cut to the left as we did at the old angle. I start my cuts a bit width to the right of my old cut and remove that material to the left once I reach full cut depth. Hope this helps.

Thanks a lot Nick,
This is very helpful. Since I'm now asking technique questions let me know if this needs to be moved to another section of the forum. I don't remember learning about making a cleaning cut. When I got trained (pretty early on, in fact I was the first officially certified gadgetman!)I just remember starting near the axle of the throttle plate and cutting a short section, maybe an inch or so, in a clockwise direction, then cut it deeper and repeat until it was full depth. Then repeat that whole sequence, sort of scalloping out little sections until done.

You guys have obviously made refinements since then. Can you tell me more about what the cleaning cut is and what the current approach is to making the cut?

I get the impression you're starting from the left side of the throttle plate axle as you're facing it (not the right side as I was doing), and probably begin your cut an inch or so short of the axle, cutting clockwise toward the axle, stopping a bit width or so short of where you want to finish up, then you move to the right another inch or so, cut that section in a clockwise direction until you reach the first section, and so on. And then you cut that last little bit width section out on the left (the cleaning cut).Is that right?

The current technique I use is to start a bit width away from the axle on the left, then cut down in until the shaft stops the cut, then cut to the left cutting out the starting width...sort of like a backwards "L". I don't recommend doing a follow up cleaning cut along the Groove as "the enemy of good is better". Cleaning cuts have a tendency to open the Groove too wide creating a decrease in results.

I understand what you're saying about not removing more material, (the enemy of good is better). So you don't cut down in layers or slices, you just go all the way down and then cut across, removing the full depths worth of material in one move?

Also, if we call the left side of the axle, 8 o' clock, and the right side 4, is it as I imagined, that your cutting something like 7-8, then 6-7, etc.?

You imagine correctly.