| Official Luthiers Forum! http://luthiersforum.com/forum/ |
|
| Adjusting a bolt on neck (PIC ADDED) http://luthiersforum.com/forum/viewtopic.php?f=10101&t=30725 |
Page 1 of 1 |
| Author: | John Elshaw [ Fri Jan 14, 2011 10:36 pm ] |
| Post subject: | Adjusting a bolt on neck (PIC ADDED) |
I'm building my first mortise and tenon bolt on neck (man, spanish heels are WAY easier than this!). Anyhow, I need to adjust the neck angle slightly. In some of the methods I've seen builders trim the cheeks of the heel to correct the angle. In others it looks like they trim the end of the tenon. To me it seems like you would have to do both. If you just trim the cheeks, it seems that when the tenon bottoms out in the mortise it would prevent the neck from adjusting. If I do trim the tenon, doesn't that affect the angle the bolts go into their barrels in the tenon? I must be missing something. Any help would be greatly appreciated. Cheers! |
|
| Author: | Darryl Young [ Fri Jan 14, 2011 10:42 pm ] |
| Post subject: | Re: Adjusting a bolt on neck |
Sand the cheeks of the heel to set the neck angle. Tenon should NOT bottom out in the mortise (may or may not need trimmed). |
|
| Author: | John Elshaw [ Fri Jan 14, 2011 11:07 pm ] |
| Post subject: | Re: Adjusting a bolt on neck |
Darryl Young wrote: Sand the cheeks of the heel to set the neck angle. Tenon should NOT bottom out in the mortise (may or may not need trimmed). So the mortise should be deep enough that the bottom of the tenon doesn't touch? Don't you want as much of the wood touching as possible for easier transfer of energy between neck/body? That seems counterintuitive, but I've only built classicals (with a spanish heel) or dovetail joints up to this point. Thanks for the info. |
|
| Author: | muthrs [ Fri Jan 14, 2011 11:24 pm ] |
| Post subject: | Re: Adjusting a bolt on neck |
The tenon shouldn't bottom out. You want good contact on the entire face of the cheeks. Dovetail joints shouldn't bottom out either, for the same reason. Besides, when you do a neck reset on a dovetail joint, the gap at the end of tenon is where the steam goes. |
|
| Author: | meddlingfool [ Sat Jan 15, 2011 1:16 am ] |
| Post subject: | Re: Adjusting a bolt on neck |
Do you mean barrel nuts in the tenon? 'Cause those should rotate in their holes to self align. If you are using threaded inserts I could see the problem, which is an advantage of barrel nuts... |
|
| Author: | Mark Groza [ Sat Jan 15, 2011 7:51 am ] |
| Post subject: | Re: Adjusting a bolt on neck |
I use barrel bolts and drill my final holes in the neck block so my bolts go in and register flush with the block. When drilling the tenon i angle to match the neck angle degrees to the barrels and everything lines up great. You can do the same thing with inserts. 
|
|
| Author: | bluescreek [ Sat Jan 15, 2011 9:31 am ] |
| Post subject: | Re: Adjusting a bolt on neck |
In all fairness there a different types of threaded inserts. The ones that Martin uses are Brass and high quality . Those Zink pieces of junk sold at some of the larger home repair centers won't make good sinkers . The advice so far is on the money . A neck tenon should never bottom out . The lock of the joint is at the neck block . If you bottom out the joint will not work. |
|
| Author: | John Elshaw [ Sat Jan 15, 2011 7:10 pm ] |
| Post subject: | Re: Adjusting a bolt on neck |
Good info guys, thanks for the help. Below is a pic of the neck and the threaded inserts. I bought the neck a couple years ago before I ever made a bolt-on neck so just assumed the hardware on mine was standard. I know better now. Anyhow, as you can see, the threads are not really adjustable and any trimming I do to the cheeks will affect the angle of the bolts. Since I dont have to adjust very much, I'm thinking slightly larger bolt holes will allow for proper fitting of the hardware. Any other thoughts? 
|
|
| Author: | Andy Zimmerman [ Sat Jan 15, 2011 7:16 pm ] |
| Post subject: | Re: Adjusting a bolt on neck (PIC ADDED) |
That is the way to do it. The tenon should NOT hit the mortice. I make my holes for the bolts in the neck block large enough so the angle is trivial. Typically I use barrel nuts instead of threaded inserts in the neck tenon so they can rotated to account for the angle difference. |
|
| Author: | Tom West [ Sun Jan 16, 2011 8:07 pm ] |
| Post subject: | Re: Adjusting a bolt on neck (PIC ADDED) |
John: Lots of folks use inserts and hanger bolts also without any trouble. The slight angle differance will most likely not be a problem and if it is you have answered your own question with the larger holes. I use the barrel bolts but would not be one bit afraid of doing it with the inserts.One thing I do is not try to fit the whole cheek. I undercut the cheek all but about 1/8" on the outer edge,then fit with the so called flossing. Good luck and take care. Tom |
|
| Author: | gozierdt [ Mon Jan 17, 2011 9:16 pm ] |
| Post subject: | Re: Adjusting a bolt on neck (PIC ADDED) |
I second what westca said. Drill the bolt holes in the body neck block slightly oversize. A slight change in the angle of the neck will not cause a problem. The main structural/acoustic connection between the neck and the body is the contact area of the heel. I also undercut the heel cheeks like westca, to simplify the fitting, and make it easier to get a really snug fit along the areas that do contact the body. |
|
| Page 1 of 1 | All times are UTC - 5 hours |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|