In the Workshop Feb 2009

I thought you might like to see my new way of slotting fretboards. First the table saw cross slide is made from two strips of oak that have been prepared to slides snugly in the cross slide slots on the table saw. I then fixed a strip of 9mm birch plywood to the oak cross slides. Next a vertical strip of 9mm birch plywood was attached and the whole assembly was fitted with a strip of mahogany to strengthen the assembly. I chose birch plywood for two reasons. First it is very stable when kept dry and secondly it was free.

On the face of the cross slide I fitted an off cut of bone top nut, Corrian would have worked as well but is not as good as bone for wear. The width of the top nut just happened to fit into the comb slots. The position of the bone slot locating bar is not critical, just place it somewhere near to the centre.

I use double sided tape to fix the slotting comb to the fretboard, a strip two inches long at each end is all that is required.

I scribed a centre line down the middle and underneath of the slotting comb and fill the scribe line with bright yellow highlight pen for visibility. This line must be parallel to the comb edge. next I draw a centre line down the middle of the glue face of the fretboard and attach the two short lengths of double sided tape to the fretboard. lastly I lay the slotting comb over the fretboard making sure that its line is directly over the line on the fretboard.
Lastly I set the height of the saw blade and cut the slots on the fretboard.

This photo shows a 650mm scale comb sitting on a completed fretboard.
The comb was cut on a CNC table router and the slots are cut to a 0.0001mm tolerance, no more guessing which part of the line to cut on with the saw. Production combs are made from Lexan.
The fret positioning formula that i use compensates for string stretch as caused by the height of the strings over the fretboard.
I can provide these slotting combs, in metric scales, for most scale lengths. Email me at sales@willisguitars.co.uk. for prices.