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Bought a bolt-on neck with neck block from Hannalei Moon which looks great. This goes with an OM kit I bought from John Hall which is first class. A quick question from a rank amatuer.

The face of the neck block (the side with the mortise) is perfectly flat. The shape of the mold, where the neck block is positioned, is slightly radiused side-to-side. I assume I should sand a side-to-side radius in the face of the neck block that matches the radius of the mold. For clarification, there will not be a radius top-to-bottom.

Sound correct? I'm assuming the neck block is left this way on purpose so it could be used on any body shape.

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Formerly known as Adaboy.......

Correct-o-mondo.

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Jordan Aceto
Ithaca, NY

Great, and thanks Jordan!

It's funny how I keep second guessing myself. It's my first build and I don't want to make a mistake.....especially on the neck block.

Thanks again!

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Formerly known as Adaboy.......

I just sanded the neck block down where it conforms to the mold........and now I have another question <smile>

The 2 inside edges of the neck block are radiused (the 2 edges that meet the rim aren't). It trimmed the nick block to length and remarked the centerline of the block using my dial calipers (measure the width of the block, set the width of the calipers to 1/2 the width of the block, and use the calipers to scratch a centerline) I scratched a centerline from each side of the block and it worked ok but the radiused corners made a split "Y" pattern on that side of the block).

To sand the block, I positioned the soundboard end of the block level with the top of the mold and lined up the centerline of the neck block with the centerline of the mold. I then clamped a piece of wood up against the neck block so I could slide the neck block back and forth against the block while sanding the face. While sanding, I kept checking the sand pattern on the face of the block and did my best to place pressure on the block so the pattern worked it's way to the middle evenly.

Now that I'm done, if I eyeball down the centerline of the mold (where the two halves meet), the centerline I scratched on the neck block is angled off to the side.......meaning I sanded more off one side than the other. I measured with my dial calipers and it appears one side is 0.030" - 0.050" thinner than the other. It's enough you can see one side is thinner just looking at it. I wouldn't have thought I would get that far off keeping the sanding pattern centered.

Now I'm worried the neck block will be angled when I glue it in......where the neck will won't to veer off to the side instead of sitting square to the body.

Any suggestions for correcting this? Also, how could I have done the sanding differently to avoid this?

Edit to add: The side of the block sliding along the clamped piece of wood didn't get sanded as deep as the other side.

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Formerly known as Adaboy.......

Darryl,
You'll need to work that block some more to even it up. The problem wont be the fit of the neck to the body, but the mortise to the tennon and the angle of the bolts. I suggest using a block plane to get close and sanding to finish the fit. That works much better than grinding away with sandpaper.

Steve

Hi Darryl,

Any chance of pictures? I will be fitting a neck from Hannalei Moon soon as well.

Thx!

Glenn

Darryl,
This block is not a mistake yet. It will only be a mistake if you don't correct it. It sounds, from our description, that the mortise is no longer parallel with the centerline of the guitar. That needs to be fixed. While I use calipers all the time when building, I find that very small measurements are easy to mess up. You need to increase the accuracy of your sanding. Here's what I would do.

Since you have the mortise already cut in you block, that makes finding the center line tougher. Cut a board the thickness of your mortise and about 20 inches long. Glue a little extension on to one end that will slide into the mortise from the top. Mark the center of the stick at the other end.

When you put the stick into the head block, sand the head block until it is both flush and the centerline is correct. Your head block my be a tiny bit thinner when you are done but that should have no effect on anything.

I often find that taking the time to make a simple measuring device that is inherently accurate, is usually faster and better than doing without.

Mike,

Thanks for the detailed response. To make sure I understand how this would be used, are you saying to sand till teh centerline of teh 20" extension lines up with the center line on the tail end of the mold?

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Formerly known as Adaboy.......

Steve,

In hindsite, i wish I had done as you suggest.....mark teh radius on each end of the block, plane close to the line, then finish off sanding. Of course I need a good plane....but I digress.

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Formerly known as Adaboy.......

Yes. Make sure you get a good snug fit on the section that will fit into the mortise and that it is perfectly lined up with long stick. It shouldn't take too long to sand it. A few strokes will move the guide stick quite a bit.

It is important to make sure that the center line of the top lines up with the center line of the tail end of the mold because that is where the neck is going to point.