Peter's link will do it. I just made a simple mdf template from the dimensions on the Downs drawing and double checked it with a neck that is Fender authorized (which should mean it meets their specs). It is tapered the 0.8 degrees on each side per the drawing. I build the neck heel to fit it and when I put it on the guitar to route I usually run a layer or two of masking tape (green) around the bearing surface, that makes the pocket a few thousands smaller than the heel. I would rather have to sand/chisel the pocket larger to fit the heel than have it loose to start withThat made a lot of sense, thank you for tailoring those pictures to my question. I recognize them from one of your build threads. I was udner the impression the centre line could not deviate. Nice to know there's some flexibility.
Here's a question...
I have my neck template prepared. To ensure a snug neck-body joint, can I trace the heel of the template onto a piece of MDF, route the waste, and use that for my neck-body routing template? I'm trying to develop my abstract geometry thought-process.
FWIW, the other end of the template is my Gibson tenon routing guide - both kinds of guitars on piece of mdf.