Points to Note.
When fitting a concert D reed into my chanters, the best result/sound is gained when the reed is sitting right down into the socket and just above the throat of the instrument, this closes of any cavitations that might be there, if the reed was to sit a little higher in the socket, the throat lies about 19.00 mm or 3/4 " down from the very top/end of the chanter.
Never make your ready sanded concert D slips narrower than 13mm, you can make them a tad wider say 13.30 to allow for the curvature and tidying up of the edges, when the two half's are tied together with the aperture plug inserted, you will find that the overall width has become smaller, say 13.00mm.
Final trimming of the lips
I have found that a pair of guillotine garden type sheers do the job very well, they were relatively inexpensive, about 8 pounds, made by Draper, they have a block of aluminium on the lower side which supports the reed nicely and a very sharp flat blade, which cuts exactly parallel.
