Neck block alignment problem

[MarkKlee]

Quick background: I'm on my 2nd build, BRW back/sides, Sitka spruce top, Mahogany neck. My first build was a Martin kit that went extremely well and I was very pleased with the end result. The first kit was a dovetail neck that fit almost perfectly from the get-go and needed very little adjustment. The second has is a MT joint and I obviously had difficulty setting the neck block properly. I just cleaned out the joint and attached the neck today for the first time and here are the results and my plan of attack. I'd love some feedback:

Neck sits 3/16 proud of the guitar body. Since my neck block was only drilled and not slotted I believe I'll need to channel out the holes to get the neck to set down further. I'll also need to extend the mortise slightly to allow a 3/16" drop. A small rasp file is the only way I see to do this.

Center line of the neck is 3/16" off the centerline of the guitar at the bridge location. I've read Ken's processes and it appears he HIGHLY recommends not messing with the cheek angles but I don't see any other option ... ideas?

Lastly, a straight edge run along the neck produces a neck angle that is 5/16" higher at the bridge location than at the top of the guitar. In other words, I believe my neck angle is off which produces too much slope - creating a 1/4" gap at the bridge. Again, I don't see any other option but to work on the cheeks to get everything squared up.

I know, I know, I created the issues myself by not having everything squared up when the back and sides were glued. The sides had some warp to them which is what I believe created the issue to begin with. I'm also a little concerned that the neck block could have twisted slightly - does anybody have any recommendation on how to measure/check this?

I'd love ANY input I can get on ANY of these problems. I think they're all fixable, but it frustrates me to have been so sloppy.

[TonyinNYC]

First get your neck to sit flush to the top before you worry about the angle. It might be fine once you drop it down. Your plan of attack to drop the neck into the mortise seems sound. Slot the bolt holes. I use a dremel with a sanding drum to make the mortise deeper when I need to. You can also take a bit off the tenon as long as you don't get too close to the inserts in the tenon.
Once the neck is properly seated, check your neck angle again and let us know where it is. You can easily adjust it by sanding the rim and take more off of the top edge to tip the neck forward if needed. But again, seat the neck fully then recheck the angle.

[ken cierp]

Ditto Tony -- First you have to get the tenon seated and the bolt holes aligned. At this point those other measurements are not dependable and most likely are not the actual dims.

[MarkKlee]

Thanks guys, I'll let you know the dimensions once I get it slotted. Any ideas on a better way other than a file? The holes are small and hard to reach ... maybe drill a small hole next to each one first?

[Bob Matthews]

I agree with the above, get the neck into its proper position with the top of the neck flush with the top of the soundboard, then check your bolt alignment.
If the bolts are way off I think I'd be looking at a way of plugging the holes and then re-drilling, or perhaps you could use a router and a long router bit to elongate the holes - depends on how thick your neck block is.
A file would be tough going but rat tailed rasps are available.
Then when you have neck flush with the top you can start to worry about the angle and the alignment.

Bob

[MarkKlee]

Nevermind on the slotting question ... I have a precision inlay tool that made the process extremely easy and fast with a 1/8" downcut bit.

Here are the results:

With the fingerboard flush with the soundboard I'm 1/4" off center at the bridge location and a straightedge is 3/8" high at the bridge location. Also, my straightedge is 1/8" high at the top of the sound hole.

The approach I took with the dovetail joint (on my first guitar) I simply sanded adjustments to the cheeks to get everything lined up. I know Ken generally tries to avoid this but when things don't line up, is this my only option? I'd love to hear other approaches.

Thanks again for all of the input.

[ken cierp]

Whoa --- stop the bus! "Ken's articles" are related to neck set angle and have nothing to do with a neck block that might have been glue in off location, a top that may have been glue with the center line angled or a neck that may be machined improperly -- beware of Ebay sellers.

That said, one can shave a bit of material off one heel cheek and not change the set angle. Which of course is an apparent option for this situation. It is also possible to get the "finger-board" on center even if the neck is skewed a little. If you have Martin neck it is most likely that the FB is pinned and you will need to shave one side of the heel -- first make sure there are no obstructions and that you cleared a recess around the tenon. As shown in here:

http://www.kennethmichaelguitars.com/neckfitpart1.html