Gluing the Neck Scarf Joint:
If you haven’t done so already, read the following articles to prepare for this important step:
Neck Wood Selection
Preparing the Neck Scarf Joint
Laminated Neck Solid Headstock
Laminated Head and Neckstock
Tools and Materials Required:
Assessing the Neck and Headstock:
Check the fitting of the neck to the headstock. This joint should be absolutely perfect. If it is not, some additional sanding and or planing has to be completed. Upon inspection that neck pieces are absolutely aligned, it is time to start setting the gluing fixture.
Anchor The Neck Piece:
The first step here is to anchor the neck piece to the gluing fixture. First – take a 2″ x 2″ x 3/4″ block and anchor it to the end of the fixture with a medium Clamp. Turn this clamp down really tight at this point.
Next place place a piece of waxed paper at the point of the glue joint. Another option that I have used is to actually wax the surface of the wood gluing fixture with paraffin wax. Set the neck heel end tight against this block and roughly parallel with the length of the board.
Use (2) large Clamps and place them at roughly the 1/4 points of the neck and tighten them up so that the neck will not move – do not crank in too much pressure with these clamps at this point, as that will come later.
Anchor the Headstock:
This step involves anchoring the headstock into place. Be precise at this point as this will be the final position of the neck/headpiece joint. When everything is in place, set another 2″ x 2″x 3/4″ wood place at the end of the headpiece and clamp it down very tight so the piece won’t move.
Take (1) large clamp at the center or slightly toward the top of the headpiece and anchor it down to the fixture – again do not crank in too much pressure at this point. Just snug it up.
Check the Fit:
Make a careful inspection of the blocks and joint and be assured that everything looks to line-up exactly.
If things look like a go, remove the headpiece clamp and place glue on the surface of both sides of the scarf joint. My preference for this joint in a slow set 2-part epoxy glue. I want to give the maximum amount of strength to this joint.
Set the headpiece back into place and put the headpiece clamp into position and snug up again.
Clamping the Joint:
We can now prepare the (2) cauls for actually clamping the joint. First of all the cauls should be either coated with paraffin wax or place sheets of waxed paper between the cauls and the joint.
Set the 3/4″ thick caul into place and hold the thin caul (1/4″ thick) on the backside of the headpiece. While pinching this sandwich together, place one of the medium clamps into place and snug it up. Next place (3) more medium clamps on the head and manipulate them into proper position.
Check the status of the joint. Is everything all lined up? If not, block may require re-adjustment as they can slide around a bit during the clamping if they weren’t anchored properly. Tighten all four medium clamps a bit more. Now tighten the neck and headpiece large clamps a couple of turns. Go back to the medium clamps at the scarf joint and crank them a few turns too.
Take a look at the joint. Everything still lined up? If not you can sometimes do some minor repositioning with a few taps of a Plastic Tipped Hammer.
Neck Assembly Jig:
If you would like to cut down your glue set-up time and get more consistent results, check out our Neck Assembly Jigs. We have these jigs available for 6-string acoustic guitars, 12-string acoustic guitars and classical guitars. They are available in our Luthier Tool Plans section, and Luthier Tools of our site, Georgia Luthier Supply.
Time to Set the Clamps:
Now we really clamp down the (4) medium clamps and at the same time crank in what you can of the other clamps. Set the neck aside to dry overnight. Remove the clamps, and clean up the joint with sanding blocks or a Low Angle Block Plane.