http://www.youtube.com/watch?v=8zFTG1Ra8Z8
Unfortunately, there was a SNAFU literally a few minutes before the end of the roughing toolpath when the loose side piece interfered with the cutter and caused it to lose steps and dig into the headstock! This was foreseeable and I did consider that this might happen but forgot to intervene and stabilise or remove it. I am preparing two further Khaya neck blanks which are wider and the cutter path will not run outside the width breaking up the sides as with these first two stocks.
I elected to continue with the finishing toolpath and I'm glad I did because it the end result was highly satisfactory. I did about 30-45 minutes of filing and sanding outside in the sun and was rather pleased with the neck at that stage. It certainly gives me confidence that the tool paths are valid and without any glitches caused by operator inexperience will run to completion and produce a fine looking neck. I was particularly pleased with the volute bump area.
The total cut time was about 2 1/2 hours but the video is condensed to less than 10 minutes.
Spindle speed: 18,000 rpm
XY feed rate: 2,500 mm/min
Z plunge rate: 120 mm/min
Depth per pass: 2.0 mm (roughing)
Stepover/stepdown: 1.2 mm (finishing)
Cutters: 6 mm two flute solid carbide slot drills (flat end for roughing, ball nose for finishing)
Material: Khaya Ivorensis (African Mahogany) tonewood neck blank (84.5 x 800 x 40.6 mm)
Spindle: StoneyCNC small industrial quality spindle
Doug
Some photos after a degree of finishing with 180 grit abrasive paper:
