Peter Coombe Mandolins and Guitars
Riser block and neck
Here is how the riser block starts out, as a quarter sawn piece of Maple that has been cut to size on the bandsaw. A good fit is achieved by sanding it flat on the linisher and,
sanding the end to 90deg, or close to, so the end fits to the end of the soundboard.
Marking out the shape.
Cut to shape on the bandsaw, and then sand the curves smooth on the linisher.
Now I prepare the cross piece. I use Ebony. Here I am cutting a strip of Ebony that has been pre-thicknessed on the drum sander.
Mark the Ebony strip.
Shape it on the linisher.
Dry fit the riser block and the Ebony strip. Looks good so now is ready for gluing.
and clamp. Wait for the glue to dry.
Once the glue is dry the riser block is shaped with chisels. Make sure they are sharp.
Shaping the dovetail. During this process the neck is fitted and checked for fit and straightness. Note how the corners have been rounded to stop the riser block from splitting.
Dry fit the neck, looks good.
Now the riser block is sanded down so it is just proud of the soundboard.
Mark out the position of the fingerboard. This may need to be done a few times as the riser block is shaped. The aim is to make sure the base for the fingerboard is kept flat.
Now plane the riser block flush with the soundboard.
Also shape the sides of the riser block and soundboard with a small finger plane.
Checking all is flat and straight. Final shaping can be done with a sandpaper block.
Dry fit the neck again.
Check the neck angle and straightness of the neck.
Neck looks straight, as referenced from the centre join of the top. Now ready to glue the neck on.
Apply glue to the dovetail join.
Glue the neck on. In this case the join required a small shim. Don't be afraid to use a shim. Is far better to use a shim and get the neck join tight and straight instead of crooked with no shim.
Finished. Glue dried and ready for the next step, gluing the back on. It is starting to look like a mandolin now.