Headblock
Tools and Materials Required:
Wood Rasps
Sanding Sticks
120 Garnet Sand Paper
Feathering Disc Adhesive
(2) Large Cee Clamps
Wood Clamping Cauls
Waxed Paper
Dovetail Saw -or- Japanese Pull Saw
1/2″, 3/4″ Chisel
We are assuming that you have already glued in your Tail Block. If not visit the article on Gluing the Tail Block, as that should be an operation that is completed prior to this step.
Remove the sides for the Inside Form again.
Trimming The Sides
Take the retaining block off the Head Block end of the Inside Form to expose the cutting slot. If you have a bandsaw, take the form with the side clamped inside the Form and run the sides through the saw to trim both sides at one time.
If you don’t have a band saw, carefully mark the center of the guitar of each side (use white pencil on dark wood sides). Remove the sides and trim with a fine-toothed dovetail saw or a Japanese Pull Saw. Now insert the sides back into the Form and re-clamp.
Final Side Fitting – Inside Form:
Now fit the sides back into the Inside Form, install the form retainer block(s) and apply the Spreader Jacks make sure the sides are exactly symmetrical within the form and that the joints at the top and bottom block are exactly on center. If not, adjust by cutting or sanding with a sanding stick. On a side note, we don’t have to have Head Block side hairline tight as the sides have the neck to cover this joint.
Cut your Head Block to shape using the layout of your Guitar Building Plans. Be sure to cut the block to exact height as both the Head and Tail Blocks will be a couple of our references for the proper side depths later on.
Shaping The Acoustic Guitar Head Block:
The acoustic guitar Head Block could be cut on a table saw, a band saw or with hand saws to match the proper outline of the block. Depending on the guitar shape the side of the block that is glued to the sides will be flat or have a slight curvature.
If the area in question is flat, (and it is with most dreadnought guitars), just finish sand the block. If it is curved slightly, slowly sand from the center of the block toward the edges with a sanding stick. Just take a little at a time and check your progress often by fitting against the guitar sides. Flip the block upside down and check again. When you have a hairline joint you are set to go.
Gluing the Acoustic Guitar Tail Block:
Do final fitting of the Acoustic Guitar Head Block. Apply glue to the block and the sides. Apply a small gluing caul to protect the block from the clamps and clamp with (2) Large Cee Clamps. Be sure to place a piece of waxed paper behind and beneath the sides and Head Block to prevent the guitar from being glued to the Inside Form.
Special Note:
Many luthiers cut the dovetail slot into the Head Block prior to gluing to make handling easier. It is up to you in which order you do this. Also there is a method where the neck is secure with either screws through the head block or tapered dowels. You do need to prepare the Head Block if you plan to use one of these techniques.
We will write special articles on the composition and construction of these specialized neck joints, since this is a very important subjest and is open to a lot of opinion.
Head Block Shaping Tips:
Here is one way to get the glue joint of the tail block perfect. Glue a piece of medium grit sandpaper against the sides where the tail block will be installed. Make the sandpaper about 1″ wider on either side of the block. Be sure to use a release-type of adhesive like feathering disc cement or something similar. Now take your Tail Block and sand it either up and down or sideways a bit. In a very short period of time you block will be perfectly contoured. Remove the sandpaper and adhesive and check the joint.
Tags: gluing the head block, guitar building tips, how to build a guitar, preparing guitar sides
