I have ordered some 4mm Ash stripes today to insert into the necks, I'll probably plane them down a bit, but we'll see how it looks first. So until they arrive I have a few days for making exact neck and headstock templates.
For now I wanted to share another technique you can use while joining veneers or tops. I already wrote about mounting the plane in the vice blade up, so that you can slide two pieces of a top over it - this is a technique that some violin builders use for bookmatching top and bottom material, usually with a larger wooden jointer plane. Alternatively you can use the shooting board again.
I had this top wood that I needed to join, the gap was around a millimeter between the pieces, with a clear concave in the middle and the edges after the cut where rough
I constructed a large shooting board using MDF, scraps and clamps. You need a flat bottom piece that your plane will glide on, another one on top, that will raise the material to be planed, to have a full contact with the blade, and one square piece mounted at 90 degrees to act as the fence. Of course you can do yourself a favor and make a permanent shooting board for yourself, or even two, depending on the plane size you will use and the material to be planed. This time I needed a big one and as you can see it's still not big enough to hold the full piece, but still it's long enough for the plane to do the operation correctly. I like to use my low angle jack for this, because it allows to take very precise cuts even with endgrain
Setting the plane to take very small shavings (you really don't want to take much off, otherwise the picture on the wood won't match), I planned the ends first, then started to take full passes. I aligned and pressed both pieces together with just my hand, no need to clamp it down really, since there is a a fence. You use the lateral adjustment on the plane to set the blade right if it has a skew.
After I noticed that the plane takes full length shavings and that the saw marks are gone, the pieces matched perfectly together. I still have some small yearly in the material on the edge, but it will be hidden under the surface anyway, so there is no need to take it down further. Here is the joined line, ready for the glue up.
So if you don't happen to have a jointer, its a great alternative.