when the entire tool sinks below the surface, you will probably find control quite difficult. a way around this is to tilt the # 40 on its' side, and cut around one side of the number. then, tilt the flat on its' opposed edge and cut the other side of the number. this will leave a bit of a raised ridge in the center most area of the numeral. then go in with a # 39 flat, and cut the ridge level with the sides of the numeral.
or, for effect, take the # 39 and wriggle the ridge. it will give a greater contrast to the engraving if that may be desired.
OK Monk, I'm going to try that. 'Lay 40 flat toward me and cut 1st part of stroke lay 40 flat away from me and cut 2nd part of stroke. Then cut or wriggle center of stroke with a 39 flat.' Thanks for the tips.
Control issues! First I need to take about a 1/4 inch off the length of my 40 flat and set up a 39 flat.
I set up another new tool an E.C.Muller 39 flat heel 10 face 45 degrees. After sharpening I purposely left the bur it made and am pleased with the result. The cuts show much more contrast then when bur is removed and heel is polished. I have 10 keys a customer wants numbered, I think I'm ready.