Monthly Archives: June 2011

Body Joint

Got the dovetail mortise cut on the body today. Compared to the dovetail tenon on the neck this was nerve wracking. the neck sits flat and firm in a cradle while the body is all rounded bumps and curves. Even with the jig I made it was still a difficult cut.

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For the jig I made a brace to the curvature of the body, where it will be clamped.

Then I dimensioned a block of plywood the same depth as the guitar body. This is for test cuts.

I proceeded to make several test cuts adjusting the template for depth each time.

Here you can see after I got the router cutting at the correct depth. The tenon fits in nice and snug.

Here I am ready for the cut and have the body clamped up.

Here you can see the cut joint. It came out fine but for some inexplicable reason it was not center back to front. I had to move it over a whole 2mm and shim the other side. Structurally and even tonally it is not a problem but after all that setup there was a bit of huffing and puffing. You can see also I have laid out the lines for access to the truss rod.

This is a straight forward plunge cut with a straight edge.

No worries there.

The neck attached to the body with the truss rod in place but not glued in.

An end shot showing the neck lining up nicely with the body. This is very important to get right. Even a slight off at the joint it will exaggerate down the length of the neck and be quite off.

As I pointed out my first cut was off center even though I checked quite thoroughly. I am not sure why that happened and will have to check it out again. Even so with the shim the end result is a nice fit and the neck lines up down the full length.

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Dovetail Neck Joint Jig

Finally got the neck joint jig ready for action today. This joint was all about preparation. The actual cut only took me about a minute but I spent several hours building the rig to cut it. It aint pretty and it’s a little bit cobbled together but it sure runs fine.

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I bought the templates from LMI. They are only 1/4″ MDF so I made a copy just in case.

Then I made a recess for the template in my top. The templates slide back-to-front to allow for adjustment in size of cut.

I ran a dado cut on the underside of the top to accept the board that the neck is clamped on. There is also another dado under the neck that has a tenon so the neck sits center.

Here’s a picture of the tenon. I am lining it up center to the template before screwing it in place.

Here I am checking how that center looks from the topside. You can also see I have the dovetail mortise template recessed on the opposite side.

A little further along. I now have both sides of the jig basically built. The board that holds the neck is hinged from the back side to allow for adjustment of the neck angle. The other side that holds the body is fixed 90 degrees. I have also added the toggle clamp to hold the neck.

Here I beefed it up a little in the front because I was getting a little sag with the weight of my router. I just use an F-clamp on the bottom.

I said earlier the neck side of the jig is hinged to allow for adjustment of the neck angle. Here is how the adjustment is done. I have a 10mm through bolt anchored in the back of the neck board and I can micro adjust with simple wing nuts anchored on the body side.

Here you can see the through bolt. There is also a wing nut on the inside of the body side to make it nice and sturdy.

Once all the set-up is complete and the neck is clamped in place it was a simple matter of cutting a dovetail tenon. All of 60 seconds.

The cut dovetail tenon. The top right corner appears to have a bit of tearout but it is only some wood fibers that didn’t get cut. They cleaned up easily. The jig cut a fine joint.

This dovetail neck joint jig was not difficult to make and made a somewhat difficult task easy. In the next step I will cut the dovetail mortise.

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Shaping the Neck Part 2

Still continuing with shaping the neck. Today I worked on three areas; the volute, the heel and the neck itself. I only have pictures of the work being done on the heel and the neck. I will try to get some better shots of shaping the volute later.

Shaping the neck at this stage is actually not difficult. And I found it to be quite satisfying. I think most importantly you have to pay attention to certain lines and converging planes. If you do that once you have your basic shape hogged out it comes together quite naturally.

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Here I am taking it down to a certain thickness. This is a tapered plane. At the first fret it is 21mm and at the 10th fret it is 24mm. Several days ago I took the thickness down to about a millimeter off on my spindle sander. Today I used my rasp to take it down to almost final thickness.

Then I used a sanding block to level it out. I check often to make sure I don’t sand off too much.

Once I had a level plane properly taken down I drew three reference lines; one in the center and two 5mm offset on each side of the center. These lines I will use later.

Then I started on the heel taking excess off with the bandsaw. It is faint but you can see I cut about 1mm off the line.

Then I used my low angle block plane to take the heel at the joint (not cut yet) down to the line. Also I planed the shape of the end.

After I decided on my lines I began to rough out the shape with a rasp. At this point it is taking shape and you can see how important it is for different planes to merge smoothly.

After I got nice symmetrical lines on the heel I returned to the neck with my spokeshave and rasp. I hogged it out with a spokeshave and did a final rough shape with a rasp. Here you can see how I use the three lines for reference. I rasp close to the line – any hills or divots and I will be able to see it clearly.

Again I used a rasp to shape it close to the line but never touching it.

Right up to the line. Later I will blend it with final sanding.

After a 120 grit sanding is done I can feel the neck is smooth and evenly shaped. Again any hills or divots, etc. I can feel them.

Close up of the heel after sanding.

The finished neck – almost. The neck still needs some final sanding (at a later time) but for now I can think about the next step of putting a joint on the end.

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Shaping the Neck

Well today was the last of four days off. And I was able to get a bunch of work done. Hence three updates in four days.

So today I started in on shaping the neck. At first it seemed there was so much to consider I felt a little overwhelmed. But after getting into it things just got done one after another.

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Here I lay out the fret placement so I can find my location for shaping the heel.
Laying out the Heel Shape

Then I made a template and penciled in my shape on the neck.
Using Template for Heel Shape

Several relief cuts were made on the bandsaw.
Relief Cuts on the Bandsaw

Then I cut it out going as far as the nut taking it to a rough thickness. I also cut the headstock to rough thickness before this cut. The plane is tapered on the fingerboard side but a single thickness on the headstock.
Cutting on the Bandsaw

Then I sand it down about a millimeter from the line.
Sanding on the Spindle Sander

When I cut the taper on the sides I will lay it down. So I need to lay out the lines on the back.
Transferring the Measurements to the Back

And before I cut the taper and loose my square edge I have to cut the neck to length and put an angle at the joint. Here after I cut a one degree angle I am checking for how far above the bridge position the fingerboard sits. Ideally they say 2-3mm is best and the one degree angle I put on it it puts it about right.
Setting the Correct Neck Angle

Here I am checking how things line up by doing a three point line sight. If any one of the points is off the center plane I will be able to see it. Unfortunately you can’t see the two points at the other end because they are out of focus. Again things look pretty good.
Three Point Line Sight

Laying out the top-to-bottom taper of the heel. I will cut this out later.
Laying Out the Shape of Heel

Here is the neck after I have cut the taper on the bandsaw and shaped the headstock.
Neck Cut to Rough Size

The headstock after shaping it on the spindle sander.
Picture of Headstock

And finally the back of the headstock where I cut a rising incline to receive the volute. Not exactly sure of the shape but I will probably carve away to the semi-circle.
Back of Headstock

Tomorrow, the next day and the next day is work so see in a few days.

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