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Neck bolt pulled out
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10104&t=56474		 Page 1 of 1
Author:  banjopicks [ Wed Mar 20, 2024 7:22 am ]
Post subject:  Neck bolt pulled out
Would the carpenters toothpick fix be good for this or something better?
Author:  rbuddy [ Wed Mar 20, 2024 7:39 am ]
Post subject:  Re: Neck bolt pulled out
I guess we gotta know how it was bolted on first. Was it a hanger bolt, a "furniture" bolt with an insert in the heel, a butt joint, a mortise and tenon, or... --- and how was it installed before it failed? Did it fail just sitting there or was there a fall or could it have been over tightened? Maybe a picture would help you get advice too.
Author:  banjopicks [ Wed Mar 20, 2024 9:14 am ]
Post subject:  Re: Neck bolt pulled out
Hanger bolted butt joint. It was stored in a bad environment and just pulled out from string tension.
Author:  rbuddy [ Wed Mar 20, 2024 10:10 am ]
Post subject:  Re: Neck bolt pulled out
If it were me, I'd consider switching to a threaded insert and furniture bolts. There just isn't a lot of holding power in a hanger bolt thread when it is going into a shallow heel in a butt joint, especially end grain.

How deeply did the screw end of the hanger bolt penetrate the heel?
Author:  banjopicks [ Wed Mar 20, 2024 1:26 pm ]
Post subject:  Re: Neck bolt pulled out
rbuddy wrote:
If it were me, I'd consider switching to a threaded insert and furniture bolts. There just isn't a lot of holding power in a hanger bolt thread when it is going into a shallow heel in a butt joint, especially end grain.

How deeply did the screw end of the hanger bolt penetrate the heel?


I'll answer this when I get it on the bench. It'll be a while.
Thanks
Author:  bobgramann [ Wed Mar 20, 2024 1:47 pm ]
Post subject:  Re: Neck bolt pulled out
A hanger bolt ought to grip pretty well. I usually use inserts and 1/4-20 bolts, but use hanger bolts when I expect greater stress. The hanger bolt goes deeper than the insert. I always put a 1/2” maple dowel in the heel with its edge a quarter inch back so there’s some cross grain for the insert or the bolt to grab. I don’t trust endgrain. If your hanger bolt had no cross grain to grab, I might consider removing the heel cap, drilling the heel, and installing a dowel. I usually have to turn the dowel down a bit to fit in a 1/2” drilled hole.
Author:  banjopicks [ Wed Mar 20, 2024 3:01 pm ]
Post subject:  Re: Neck bolt pulled out
I'll keep that in mind, thanks.
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