4 scratch build

[Simon Barden]

Ahhhgh!

Have you any idea where the 4mm error crept in? Is the file measuring from the previous slot position, and so compounding any positioning errors inherent in the cutter? If so, can each slot be referenced back to the nut instead?

And is it worth in the future marking the slot positions in pencil first and doing a very shallow run with the cutting bit so you have a quick visual guide as to whether the slots are going in the right position? It could save a lot of wasted time (and wood) if it's obvious there is still a problem next time.

[Rabbit]

Ahhhgh!

Have you any idea where the 4mm error crept in? Is the file measuring from the previous slot position, and so compounding any positioning errors inherent in the cutter? If so, can each slot be referenced back to the nut instead?

And is it worth in the future marking the slot positions in pencil first and doing a very shallow run with the cutting bit so you have a quick visual guide as to whether the slots are going in the right position? It could save a lot of wasted time (and wood) if it's obvious there is still a problem next time.

The board with the error was marked and cut by hand. The one done by CNC was within 0.2mm all the way along the line. To prevent the bit from breaking, each pass is done at a depth of 0.008 of an inch, at a feed rate of 5in/min (the software is set for imperial.. it kept rounding up in metric)

The machine refernces off the home position, so it effectively does each slot from nut to fret. The dud board was marked by hand with a pair of digital calipers and a marking knife. As someone with a scientific background I was all too aware of the dangers of compounding error of fret to fret measurement, but that seemed like the only option since I don't have a 600+ mm set of calipers. I did see a method that reduced the number of fret to fret steps, but there was still the inherent risk of compound error.