Help - Neck joint issue

[Mark Scrivener]

Made a big boo boo today.....After gluing the top and back and removing the body from the mold, I discovered I didn't have the right saw for trimming where the sides overlap the dovetail joint, so I decided to use the trim router - forgetting I was using a straight trim bit into a dovetail joint. Arggghh...

So here is the damage (see photos). Using a straight file I filed the mortise (instead of the tenon) to lower the neck properly into the joint, being carful to preserve the angle of the joint. As you can see from the shaded area, there is still some damage remaining. But more concerning, with the neck full depressed in the join, I can push on the back of the neck and tilt the neck forward. How do I correct this?

the dammage:

[Mark Scrivener]

Here you can see the neck is level with the top and appears to fit well:


Angle has not been set yet, but not way off:

[Mark Scrivener]

But here we see the problem. At rest the neck joint looks fine, but when pressing up on the back of the neck you get rotation and this gap appears:

[Kevin Sjostrand]

Hi Mark
Its a bit hard to tell for sure what you have going on there. However what it looks like to me is you had planned on doing a dovetail joint, but now you don't have a dovetail in your mortise. So its seems to me you will need to make this a bolt on neck. Fairly easy to convert this with a couple of holes through your heel block in the body and some inserts screwed into the tenon on your neck. The fit to the body you will have to adjust by taking material off the upper portion of your neck heel to get a tight fit to the body and get your neck angle adjusted properly. It appears you have a fair amount of wood to remove to do this, but it should be doable.

Kevin

[Skarsaune]

As Kevin said, a bit hard to see exactly what you've got going on....but I think you just removed the very corners of the dovetail pocket with the router. You didn't completely remove the angled portion that mates with the male dove tail on the neck, right?

If so, you just need to shim your male dove tail and refine the fit. As it sits, the bottom is loose, and it also sits too far down in the pocket.

John / bluescreekguitars videos on youtube on setting a dovetail are so good, I rewatch them everytime I'm fitting one.

[tippie53]

you have a typical loose joint. I don't think the boo boo is an issue at all as the working part of the joint is the deeper part. You may call me.
Now let me tell you what you may need to do, as this is not hard to fix.
never assume hand pressing a joint is a good test , I always clamp them, then I can wiggle to see if they are really tight and good fit.
Also break the sharp corner when the sides come to meet the dovetail joint. Also is your fretboard glued on? I don't glue them on till the neck is set and tight.

so here is your fix.

A your neck angle looks a touch low as I want the fret plane to be about 1/16 of an inch over the top of the bridge.
B using a shim is acceptable

so here You know the lower part of the neck is loose so add a shim Don't glue it yet
and use chalk in the joint to read your mating surfaces.

Clamp it TIGHT so you get a good read. You want the lower 3rd of the tenon to have chalk the upper part near the heel can be clean , as you want the tenon to pull the neck into the joint.
this video may help
https://www.youtube.com/watch?v=FNcbA1P95KE&t=1010s

[MaineGeezer]

Shims. You may be surprised how thin a shim you need.

I've always shimmed my neck joints to get the neck to sit at the proper height and be tight. Maybe somebody can cut a dovetail joint so the neck fits perfectly; I sure can't.