Neck pocket angle routing jig

[pypa]

I wanted to share the jig I made for routing the neck pocket on the Gibson I'm making.

I've use online calculators and full scale drawings to compute the right neck angle on the past couple builds. However, despite best efforts, I rarely get it spot on; it's been off by a half degree or so. There are ways of course to work around this. But the more I make, the more I wanted to take the stress out of the routing part. I wanted a way that would also allow easy tweaking of the angle after fitting.

Plans call for angling the neck, but I find that hard to do unless the taper is cut on the blank. Also, it requires undercutting the end of the neck to be perpendicular to heel - not the fretboard. This is just a pain to do. Last, this method does not allow easy adjustment after the the rest of the neck taper is defined.

I came up with this: a piece of hardwood onto which I cut and joint a 3 degree taper. A softer wood is easier to tweak, but will be altered under repeated contact with a router, so it's worth it to use something more durable and with very little flex... I used the original flat neck template to route a recess in the taper jig.

Next, I screw it to the body, screwing through where the pickup will be. This location is kind of critical. It has to be close enough to the pocket to allow the taper to sit flat and to pull out any bow that might develop in the base.



Next, I use a forstner bit to drill out the waste, taking care of course to drill about 1/4" shy of the final depth.



Then I use a template routing bit (diameter to match the pocket corners) to flush the bottom and sides. I prefer to do this at the router table to prevent tipping and to allow finer depth control, but it can be used with a plunge router as well.



You can see that the actual angle is measuring about 3.3 degrees. I can probably get away with this, but the plans call for closer to 2.8.



To achieve this, I shimmed the tips up with some business cards. The paper is nice because it compresses slightly, so when you screw down the jig, I was able to adjust the actual angle by not fully torquing down the screws. The screws allow the jig to be precisely re-set to the exact original location, so the pocket is not enlarged.



Then back to the router table. You can see how precisely it works by the barely removed the pencil marks



Voila! 2.8 degrees.



Now I fully recognize that this level of accuracy might not be required - that's what saddles are for!!! But regardless, it still makes AIMING for the right number a lot less stressful.

The jig also gives me the option to adjust a little bit if I've miscalculated. It's easier to make the pocket shallower, since the opening side depth is not affected. Making the angle more acute would require shimming on the other side of the screw and making the pocket opening at the neck slightly deeper. Options.

 

[Freeman Keller]

Are you carving the top? Are you going to angle the top where the fretboard extension sits or will the neck stand proud of the top?

What I do is far simpler. I know the angle that I want the neck to be - I simply plane that into the upper bout

Then I screw a flat router template to the top at that angle

and finesse it as required.

 

[pypa]

Freeman, I do the exact same on a carved top. That's a way better way. This is a flat top, though and can't have the fretboard and top in the same plane.

Now that I am thinking about it, I wonder if one can plane down the 'bout' even on a flat top... I can't see a downside to doing it your way - unless it would alter the aesthetics in a bad way.

 

[Freeman Keller]

If I was doing an angled pocket on a flat top I would use my same template and just shim the far end until the angle was right. As a mater of fact that template is Gibson on one end and Fender on the other and I think it has made every neck pocket in every sold body guitar that I have built.

The reason the neck is planed down like that is so it is at the same level as the rest of the binding all the way around the guitar. If you are doing an angled neck on a flat topped guitar you want to give the neck some overstand and put a wedge under it.

 

[pypa]

Yes, I already calculated the overstand. The '0' point is where the neck enters the body.

If you are shimming, then you are in essence doing what I'm doing, right?

While it is 2 steps, perhaps an easier way to do this (note to self for next time), is to make 2 templates: 1 is the standard, flat neck template that is used for sizing the hole (specific to whatever guitar one makes). The second would be a stable board with an oversized neck cut out. Use the first to make the hole about 1/4" deep. Then switch to the other, shimming to achieve the right angle, and using the previously routed wall as the bearing guide...

 

[Freeman Keller]

We are accomplishing the same things. I don't like the idea of building a jig fixed at a particular angle since every one of my guitars has been different - depends on the amount of top carve (if any), the particular bridge, scale, yadda yadda.

One little trick - I use the same template to make the neck tenon and route the pocket. When I do the pocket I put a couple of thicknesses of 1/4 inch masking tape on the bearing surface - that makes the pocket a few thousands tight on the tenon. That gives me a little more material to floss away as I set the neck.

 

[pypa]

Curious how you use the pocket to make the tenon. I can see using the tenon to make the pocket template...

 

[Freeman Keller]

Curious how you use the pocket to make the tenon. I can see using the tenon to make the pocket template...

I band saw the neck tenon be a hair wider than the final width. Then I bring it down until it just fits in the template.

Finally I route the pocket in the body with the same template but with the masking tape (green stuff). You can see in this picture that the top is sloped from the neck pickup to the end of the body I have still put a shim under the other end to keep the surface flat

Neck is in the pocket and I'm finalizing the plane from the top of the neck to the body. I want that perfectly flat with no humps or bumps. You can also get the idea that the top on this critter is anything but flat.

I'm going to show one more picture - this is a different guitar (I didn't dare try to hold the double neck up by friction of one neck but I think it would). A neck joint should be nice and snug. No glue

 

[pypa]

I see. Thanks. On my first build I band sawed and then planed to fit, but found that I did not bandsaw aggressively enough to the line. I then had to be careful to a) Not plane the side wall of the neck out of square, and b) Not plane both sides unequally so the truss rod and neck are no longer perfectly aligned to the center line. I failed a little on b.

To eliminate having to be that aggressive and careful, I find it easier at this stage to have separate neck and pocket templates.

I am making (so far) guitars in a pretty narrow range right now, so I don't mean to question your methods or present mine as anything more than a neophyte's attempt to learn and improve. In that range, however, I have found the angles to usually be around 3 degrees. So, using a template roughly sloped to 3 degrees means for the typical carved top with a tune-o-matic or fixed bridge, I'm within shooting range without having to shim dramatically.

The tapered neck jig also reduces flex reducing the size of the shim required (even a little bit of flex has upset my angle slightly). Second - and this has turned out to be a real practical concern for me: a template routing bit has to ride along a reference surface. When shimmed, that wall is interrupted and the bearing on all of my template bits are addicted to crack and will find it despite careful depth setting. So minimizing it is a feature for me.

Anyway, thanks again for all the detailed and constructive advice you've given me over the past few builds.

 

[Freeman Keller]

I have two sets of commercial plans for Gibson style guitars - the vintage LP calls the neck angle at 85.6 degrees (4.4), the 335 plans call for 88 (2 degrees). I have built guitars from both. I also built an LP with a thin top at 3 degrees and as I recall the double neck ended up at 3.5.

Every one of these has been finessed after I get the basic routing done - it really doesn't matter what the number ends up, I want the correct geometry. I start checking before the final pocket depth has been established - its always easier to take a little more off (or change the angle) than put it back on.

Here is that old double neck again

Basically what I'm saying is that each guitar is an individual (unless you are mass producing of course) and the combination needs to be worked out for it.