cracked tenor neck build in progress--Salvageable?

I am building a series of three tenor ukes. I just noticed a crack has formed in the neck at the heel of the neck. It was to be a Spanish heel neck to body. It has a stacked heel. The crack is just under where the fretboard will go, and just above the stacked heel. The cleseup shows an 8cm ruler showing the less than 1/2mm crack at its widest end. The other photo shows the calipers indicating the distance and direction of the visable crack, about 20cm. The crack is visable in the endgrain at about a 6mm depth. In my furniture making I would glue in a couple of hardwood dowels, if not visable, and continue. With this uke neck I can visualize some watery super glue added with clamps, but will the sound be affected? By the way, my fretboard will be ebony, and I could make it overthick if need be. Between the spline in the center of the neck and the ebony fretboard I think this neck will turn out to be quite stable, if that matters. Thank you in advance. Michael

Yes.

Use little wedges to hold it open to get glue in there, take the wedges out and wiggle the two parts back and forth to wick glue into the thinnest parts, then clamp.

After drying, i'd hit the thinnest end (closer to the nut) with thin ca and observe any further wicking of the ca along the crack (hopefully not)

Good news this neck could be slavageable. Regular Titebond most likely will not wick into the crack, even with the crack wedged open slightly, so I assume you are suggesting a good grade of super glue of an appropriate viscosity with the wedges, no? Thanks Beau for the go-ahead. Michael

Will the repaired crack be exposed at any point when the neck is shaped? Whether the glue line is visible if your shaping exposes it depends upon the wood, the glue used, the finish that goes over it and a bit of luck. If it ends up that the glue line and/or any glue (i.e., particularly thin CA) that soaks into the nearby wood is visible, you might wish that it weren't. Some people shape the neck before the board is glued in place and some after. If you are an "before" person, you might be more comfortable giving the glue routine a try and then seeing how it goes because you won't be risking tossing out an ebony board if the appearance of the repaired crack isn't to your liking.

Don't hesitate to report back! We all learn from this sort of thing.

Saltytri, thanks for the feedback. The crack at the endgrain tells me I have about 8mm, which should be plenty. The crack's runout is toward the center of the neck, so that's good. My guess is the superglue color variation will be well within the neck, also probably no problem. Good points, appreciate it. Michael

Have any thoughts about why, or when, it cracked? To me, that might influence how I felt about trying to fix it versus abandoning it now. If it's a fresh crack of unknown origins that appeared suddenly after the blank was cut to size, hopefully that's not an indicator that the wood is not stable (and may crack elsewhere, even if it remains true). If it's simply an old check that has existed for years in a thick board and you just happened to saw into it just now, well - it's probably quite stable and not worth worrying about.

dwizum said:

Have any thoughts about why, or when, it cracked? To me, that might influence how I felt about trying to fix it versus abandoning it now. If it's a fresh crack of unknown origins that appeared suddenly after the blank was cut to size, hopefully that's not an indicator that the wood is not stable (and may crack elsewhere, even if it remains true). If it's simply an old check that has existed for years in a thick board and you just happened to saw into it just now, well - it's probably quite stable and not worth worrying about.

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I have looked for a telltale bit of heavy lignan along or near the crack. I see really no indication what caused the crack. My feeling is the clamping of one of the blocks caused it, but I cannot account for it visually. Also, being so near the end of the neck, that might have something to do with it. I think I will add the super glue and take it from there. I will report back. Dwizum Thanks Michael

If it was me I would just wick some thin #10 CA glue into the crack and skip the wedges and clamps. Then set it aside for a couple weeks to rule out checking. It will be covered by the fretboard so who cares? No need for the extra think fretboard either if it was me. These sorts of things happen.

sequoia said:

If it was me I would just wick some thin #10 CA glue into the crack and skip the wedges and clamps. Then set it aside for a couple weeks to rule out checking. It will be covered by the fretboard so who cares? No need for the extra think fretboard either if it was me. These sorts of things happen.

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Sequoia, Thanks for the post. I am a bit afraid of wedges since the crack is less than 1/2mm at widest. I think I will run some CA into the crack, do it again, maybe again, carve the neck, then put it away until time to put neck to body. At that time I will run it lightly through the jointer to make sure it's true, and hope I can call it good. Although made from well seasoned mahagany, resting it for a couple of weeks will allow any movement to happen. I have lightened-up considerably on this problem and think it is a small problem since reading the above opinions. Cheers, Michael