1926-style 3 conversion- I just saw this little crack while snugging up the head. Is it a major concern?
No, that is where one layer is lapped over and I have seen that on rims before. If it would separate more than I would apply wood glue and clamp it but I think you are safe like it is.
It looks like a crack, sorry, Roy
The rim builders learned to offset the laminations away from where holes are drilled
Otherwise I concur, it can be stabilized
The way that the tone ring / rim meet (just above the co-rods) i'd say your rim is "egged out" of round, probably from the co-rods being too tight (in the wrong direction), which is probably responsible for the delamination / crack / ply separation, or whatever that "flaw" is.
Here's a close-up of the scarf joint on a '27. They put it right where the co rods go, probably to keep it pushed together.
I would say that your joint came open because the rods were pushing against it beside the joint, which compressed the rim at that point. It seems like an easy enough thing to fix.
It looks to me that you rim is out of round. As mentioned, most likely because the coordinator rod is too tight in the wrong direction.
What leads me to believe this is that your tone ring to the left of your issue is hanging over the rim.
I don’t have an answer in regards to how to correct it, but I would consult in detail with Ken above or a qualified banjo tech who knows pre war instruments.
I’m pretty sure as far as issues go, this is a minor fix if done in the right hands.
It depends on how old the crack is
Clamping it with glue might not be the solution
I suggest you keep an eye on it
Measure the rim diameter there and at 3-9 o clock
I think clamping it with glue is not the right solution, since the forces that caused it to open are still present. On an old banjo rim like that, which qualifies as a valuable antique, I would opt for filling and stabilizing it.
I get them in my shop where someone has embedded a big lock washer in the rim to try to adjust the rods.
That's what this looks like to me.
Laminated rims have built in flaws. Trouble is, millions of notes get played on them.
Based on all the great comments, I went back in to check it out.
Probing around with a pin I find it is a surface crack with no depth into the wood. I measured the ID in 8 places and it is 9 3/8" all around. The rods are neutral putting no stress on the hoop. The washer divots are old. Action is good with no fret buzz at all. I am going to keep an eye on it to fix it if it gets worse. Thanks for all the insights, so much experience here.
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