Hybrid Steinberger Bass Project

[Gilmourisgod]

I have an original 1986 Steinberger XP2 bass, which had a graphite composite bolt-on neck and a wood body. I always like the tuning stability of double-ball tuners, headless design,and super-slim neck on this bass, but it always sounded a bit sterile. I started making this one-piece mahogany body for it a couple years ago, and the project fizzled when I ran into some roadblocks. I really want to finish it, hoping for some advice to move forward. This will be my first time posting photos on this forum, here it goes:

This is a photo of the my original hardboard template, a plywood mockup, and the mahogany body as it stands today. I loosely based the design on an Alembic Mark King Deluxe bass, but adjusted proportions to my liking. The cut-out at the rear is for the Steinberger bridge tuner assembly. I had no idea how the balance would turn out with a headless neck, so I built the plywood mockup to test it out, balances quite nicely for seated playing, and feels good with a strap standing, which is just random good luck on my part.

A couple more body shots:

Here it is with the neck in loosely in place. The neck fits the pocket nicely, but the pocket is a little cock-eyed.

Here's the painful shot, with a straightedge aligned to bridge and body center, the neck is out of line by about 1/4" towards the G string at the nut. Ouch! This is where everything came to a grinding halt two years ago.

The neck heel has a beveled profile from fingerboard down to bottom face as shown here against a square.

I didn't know how to go about routing an angled pocket, so I used a straight pattern bit, which leaves the pocket a hair too wide at the bottom if it's correct at the top, which creates little triangles of empty space along the bottom edge of the neck pocket. I had intended to infill these with a thin strip of wood or some mahogany dust and epoxy mixed to "bed" the neck into the pocket for full contact. It's probably a fat 1/16" of air showing.

Saved the best for last: An evil gouge in the nut end of the headless neck. I nearly wept. Near as I can determine, the shiny black surface is just jet-black gelcoat. You can see the carbon fiber substrate below. I can easily get black gelcoat, but blacks can vary considerably, I'll have to experiment with it. Any advice on patching this as invisibly as possible appreciated.

As I see it, I have two options to correct the neck pocket:

1. Glue in new strips of mahogany and re-route the pocket correctly with beveled walls to match the neck heel, no clue how to do this. My initial attempt must have gone awry due to inaccuracy in my template making skills, as I cut this directly from the template.

2. Gradually chisel,file and sand away enough wood off the neck pocket sides to straighten the neck, and then "bed" the neck in a mahogany dust/epoxy mixture.

Any advice (no matter how brutal) greatly appreciated. I'd really like to salvage this one, the mahogany blank is lovely despite my screwups.

[LightninMike]

You will need to set the template at a 7* angle to accomplish what you want

fill the sides in with cutoff wood in the same grain orientation.

then line up your template - one with a centerline on it and a centerline on the body drawn in pencil

drawing the centerline will be interesting due to the compound angles in the pocket

route the pocket

[Gilmourisgod]

I guess what i was picturing was a set of rails either side of and parallel to the long dimension of the neck pocket, each wide enough to carry the router base. The rails would be beveled strips, thicker at the side closest to the pocket, and beveled to match the neck heel angle. This would angle a pattern bit to cut the right bevel. The bottom of the neck pocket is good, so I'd have to set depth on the pattern bit just short of bottom and chisel out the last little bit of glue-in strip. Has anyone don something like this, any suggestions or photos of a similar jig? Maybe I should trial and error on scrapwood until I get it right, then try on the body?

[Gilmourisgod]

I guess this thread should probably be in the "In progress" section. If the Administrator wants to move it, pleas feel free.

[LightninMike]

You hit the nail on the head.

OR

i don't know if this would work as it is a bottom bit, but maybe

http://www.rockler.com/bevel-router-bit-3-8-x-7-degree-1-4-shank?utm_source=google&utm_medium=cpc&utm_term=&utm_content=pla&utm_campaign=PL&gclid=CIDrn6bBirwCFcFj7AodXggAqQ

with some modification to the bit(remove the bearing portion), it would work.

Edited January 19, 2014 by LightninMike

[Gilmourisgod]

I glued a couple strips of mahogany to the sides of the pocket and made beveled rails to let router ride along at the 7 degree bevel to match the neck heel. I have a top bearing pattern bit that will ride along the edge of the rails , which are also beveled. The trick is going to be setting up the rails parallel to the neck heel, which also has a slight taper from back edge heading towards the nut. I'll be cutting out most of what I glued in, but hopefully the neck will end up centered this time. A painful lesson in planning ahead!

[Gilmourisgod]

Success! I built this one-time jig with beveled top and inside faces, set parallel to the tapered neck and centered via leveling laser, and re-routed the neck pocket, which is now a compound bevel, tapering inward on the neck pocket sidewalls top to bottom and front to back. The laser really helped, a cheap Sears model that can rotate to throw a vertical line that allowed me to line up body centerline, center neck heel, and center nut.

I ended up cutting virtually all of the e-string side shim away, plus about 1/16" (hence the neck twist!), and leaving about 1/16" on the g-string side. The neck fits into the pocket with firm hand pressure now, dead nuts on center. Should I finish the neck pocket with Watco Danish oil like the rest of the body will be, or leave it raw? Having cut the neck pocket in dry winter conditons, should I worry about it getting too tight in humid weather?

I have yet to drill the neck bolt holes in the pocket. The neck is all beveled faces and radiused edges, so it's really difficult to take accurate measurements off it to template the bolt holes. I was thinking I could use dowel centers or something similar set into the threaded brass neck inserts, drop the neck straight down into the pocket (the only way it can go in, given the compound bevel pocket) and then tap to mark the bolt centers. Suggestions?

[LightninMike]

. I was thinking I could use dowel centers or something similar set into the threaded brass neck inserts, drop the neck straight down into the pocket (the only way it can go in, given the compound bevel pocket) and then tap to mark the bolt centers. Suggestions?

sounds like a good plan, just be mindful of the taper as it won't exactly fall in, although if you use short screws cut off and sharpened it should be fine with a good eye and a steady hand

[Gilmourisgod]

Thanks Mike. I have some spare screws for this, actually just hex-head machine screws that I can cut down and grind to a point on the tool rest of my grinder. The machine screws won't be threading into the wood at all, so I guess I have a tiny bit of slack in the setup anyway.

[SwedishLuthier]

nice save! If I have a neck that has the holes already drilled I usually do exactly like you say, use short, sharpened screws in the neck and push it lightly into the neck pocket to make a mark, then drill from the neck pocket side.