Planing for guitar back and top seams

[Richard Hutchings]

I just finished doing these glue ups right off the plane, no sandpaper, I'm stoked. At first I tried a shooting board and my #5 BU with not so good results. I then tried standing the boards up in the vise and planing them. Still no joy. Someone on another forum mentioned that it looked like I was taking too big of a bite. That may be so and I'll have to wait for the next build to experiment with that. My next move was to use my Stanley #3 set to a fluffy shaving. This worked perfect. The shorter sole doesn't make much sense to me why I got better results. It may be because it was easier to control on these very thin edges, I don't know but I'd love to hear your opinions.

505734

[John C Cox]

Yes. Super thin, fluffy shavings when jointing, especially when we're talking edge joints on plates ~1/8" thick.

The next part is clamp/hold location. Planes tend to cut deeper where the part is clamped and shallower between clamps. Over several passes, you will generally find the hollowing under the clamps.

As such, you can use this to control the jointing process. Say you're a little fat in the center.. Clamp in the center and take 1-pass or 2 passes, then candle. Repeat as needed, shifting clamps around as you go, to work through humps until the whole joint candles nicely.

If you err in joint prep, it has to fall under the fretboard. Watch out, though, as you want the joint absolutely perfect starting from the sound hole, under the bridge, and to the heel of the guitar.

Don't follow the old furniture adage of jointing tight on the ends and loose in the center. This isn't a coffee table. The center seam absolutely will separate under the bridge due to string tension.

Thanks.

[Richard Hutchings]

Very interesting. I hope I remember this for the next guitar. It will be interesting to see this in real time.

[Robert Hazelwood]

What was going wrong with the first attempts with the bevel up plane? If you are getting tearout the depth of cut will not be consistent and the glue joint will not look good or be as strong, so job one is to eliminate that.

Otherwise the usual problem is planing a hump into the edges, so that when put together there are gaps at either end. This can be caused by concavity along the length of the plane sole or by user error- its very easy to take bigger bites at the beginning and end of the stroke. You have to really focus on keeping all pressure on the toe at the beginning of the cut, and on the heel as you end the cut. If it planes too much off the ends no matter what you do, then I'd check for a concave sole; even a thou or two can make this process frustrating. You can generally correct the hump by taking stopped cuts in the middle, avoiding each end, until the plane stops cutting, then do one or two complete passes until you get a full length shaving.

The Stanley #3 is well-suited to this job. The joint is not so long that you really need a large plane to do it, and a Bailey pattern will be easier to set up for not tearing out the grain than the bevel up.

[Richard Hutchings]

If I remember correctly, tear out was one of the issues with the BU plane. A couple of passes with the Stanley and it was perfect. The only clamping was at the bottom of the vise. The edges I was planing were sticking up 6" above the jaws. This worked so well for both the top and back that I'll never bother with a shooting board for this process again.

[John C Cox]

I've jointed guitar plates with a block plane... Bevel up vs down isn't the primary problem. The factors for me are:

Well set plane with the mouth closed appropriately.
Very fine shavings
Super sharp

The main point of the shooting board is to keep the plane square to the work. The last thing you want is to wobble back and forth and crown the cut or chamfer it.

[Richard Hutchings]

I don't think it matters if the plane tilts left and right as long as your planing both boards at once. At least that's what I've always heard/read. I guided the #3 with my fingers and instinct only and both joints came out perfect.

As for my BU failure, I honestly never looked at the mouth opening as I should have and I should have given it a new edge before starting as well.