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Help fitting neck
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=22947		 Page 1 of 1
Author:  James Orr [ Thu Jul 02, 2009 6:38 pm ]
Post subject:  Help fitting neck
I've been having trouble fitting a neck from CNC Guitar Parts. Problem is due to me gluing in the neck block ever so slightly off square. When I use my center line finder, the neck is about a centimeter left of the center line at the tail. I tried shaving a bit off both sides of the mortis and am able to wiggle it into center, but it goes back to the left when I tighten the bolts. Any ideas? Or should I scrap it and hope acoustic #6 is the first one I actually finish?
Author:  Darryl Young [ Thu Jul 02, 2009 7:11 pm ]
Post subject:  Re: Help fitting neck
You know I'm no expert......but are the holes in the neck block large enough to allow the bolts to align 1 cm off to the side? Possibly they are holding the bolts so the neck pulls back to centered position when tightened. Just a thought.
Author:  R W Goodman [ Thu Jul 02, 2009 8:21 pm ]
Post subject:  Re: Help fitting neck
So your neck block is centered but not square? Can you sand the sides to square it a bit? I imagine when you tighten the bolts the heel of the neck will always want to square itself to the sides no matter where the tenon is. Im newer at this than you though...
Warren
Author:  Tom West [ Thu Jul 02, 2009 8:45 pm ]
Post subject:  Re: Help fitting neck
James: If your neck is centered where it joins the body,but is tilted to one side or the other,then you have to remove material from one of the cheecks of the neck to allow it to swing over when you tighten your bolts.Try to keep the two cheeks parallel so that the two cheeks will seat correctly at the same time.With this much offset you may have to work with a chisle at first and then floss into fit with sandpaper.This is said with some assumptions, the body of the guitar is flat at the neck joint, the neck tenon does not bottom out in the mortise and can tilt sideways enough to correct the problem.Suggest you also look in the video section ,this whole thing may be covered there.Also when you finish this you have to set the correct neck angle,if you work carefully you may be able to do both at one time.Recommend working as two seperate problems.
Author:  James Orr [ Fri Jul 03, 2009 12:48 am ]
Post subject:  Re: Help fitting neck
Many thanks. I did just as West suggested before posting by removing some material from the side of the tenon. That allows me to center by hand, but the neck pulls back to it's off-centered position when I tighten the nuts.

It all comes down to radiusing the neck block. The body shape I'm using isn't square at the neck to body joint and has a small radius. When I was sanding the radius I must've turned it ever so slightly,

I've decided that if this isn't a fixable problem, I'm just going to bolt the thing on and be proud of building a guitar. I'll find a radiusing solution for the next one.
Author:  woody b [ Fri Jul 03, 2009 7:30 am ]
Post subject:  Re: Help fitting neck
If the neck fits until you tighten the bolts then the bolt holes must be offline a little. I'd try using threaded studs and nuts instead of bolts. You can bend the studs slightly to make up for the angle. If it doesn't work all you've got is a couple bent studs, and you can put the bolts back it.
FWIW, I've never done this but it works in my mind.......but my mind is a large empty space wow7-eyes
Author:  Pat Foster [ Fri Jul 03, 2009 9:09 am ]
Post subject:  Re: Help fitting neck
James,


Removing material from the side of the tenon allows the neck to shift left or right, but it seems that yours should be rotated about the joint, like the hand of a clock. To do that you'd need to remove material from one of the cheeks, not the side of the tenon. This is a standard part of fitting a neck. Though yours needs more than most, it seems it should be fixable.

As Tom said, it can be dealt with as two separate issues. Align it to center first, with a good fit (no rocking when held together by hand), then do the neck angle, again with no rocking when held by hand. If anything moves as you tighten the bolts, it means the bolt holes need to be opened up.

Attachment:
joint.jpg


HTH,

Pat
Author:  Hesh [ Fri Jul 03, 2009 10:36 am ]
Post subject:  Re: Help fitting neck
Hey James bro here is a link to a neck fitting toot also for a John Watkins neck. The left-to-right as well as the neck angle are things that we have to fit with flossing and at times the judicious use of more aggressive tools such as a sharp chisel. But wait - there's more.... :D

The holes not lining up is par for the course since as we radius the rim upside down in a dish we remove material from the top edge of the rim which will later contribute to the neck when inserted into the mortise being proud. I find that using double stick tape and a piece of scrap wood 1/8" thick taped to the top of the neck block at glue-up nearly eliminates the hole/bolt miss match in respect to the up and down fit of the holes and bolts. This of course is part of a methodology that also includes not radiusing the top edge of the sides before gluing to the blocks and sanding a 25 - 28' radius into the top of the rim in a dish. Some elongating of the holes with a round file is not uncommon with any commercial available neck. I had a toot here about shimming the neck block for glue-up but that server is now long gone.

The neck moves when you tighten the bolts because the holes are not perfectly in the place and direction that you need them. Elongate the holes with a round file carefully noting which direction since it is reversed from the mating neck. Don't ask me how I know to be careful about noting the correct side to elongate the holes... Also remove material from the tenon until the neck can be bolted into it proper place with no movement when the bolts are snugged. When this is accomplished add some mahogany shims gluing them to the tenon side(s) to fill gaps and then removing material from the shims until your tenon fits with good wood-to-wood contact all around and Bob's your uncle - mine too.... :D

Lastly it's not uncommon with a commercial neck to also have to either pare away some of the bottom of the tenon (the curved part) or elongate the mortise with a Dremel and a sanding drum. If the holes don't match up the end point of the tenon won't either. Again, shimming the neck block 1/8" at glue-up can eliminate this miss match too.

Here is the link: http://www.luthiersforum.com/forum/viewtopic.php?f=10102&t=15022%22

Good luck.
Author:  L. Presnall [ Fri Jul 03, 2009 10:51 am ]
Post subject:  Re: Help fitting neck
Howdy Hesh!! :D I was beginning to wonder where you went! Happy holiday!
Author:  Shane Neifer [ Fri Jul 03, 2009 11:44 am ]
Post subject:  Re: Help fitting neck
James! You can't really mean that it is off by a centimetre, that is nearly 1/2 an inch! If that is the case then it is probably too much to move. So you could glue in a block into the mortice and re-rout it on centre and then drill new holes. It will be finicky precise work but it will also be good practice! If the difference is less than that then do as Pat and Hesh suggest.

Good Luck buddy!

Shane
Author:  James W B [ Fri Jul 03, 2009 4:09 pm ]
Post subject:  Re: Help fitting neck
HESH MY BUDDY bliss
SKIN
Author:  James Orr [ Fri Jul 03, 2009 10:37 pm ]
Post subject:  Re: Help fitting neck
Thank you all, and Hesh, it's GREAT to have you chiming in to aid me once again. Shane, the mortise itself IS centered, but the angle of the mortis is slightly askew. The centerline is centered at the neck block, and 1/2 off at the tail, like the long arm of a clock pointing to 33 minutes.

I haven't worked on it much today . . . I was off riding horses by a dogwood lined stream and getting ENGAGED!!!
Author:  Lillian F-W [ Fri Jul 03, 2009 10:45 pm ]
Post subject:  Re: Help fitting neck
Congratulations James!
Author:  James W B [ Sat Jul 04, 2009 9:12 am ]
Post subject:  Re: Help fitting neck
James don`t do it.Just kidding.I`ve been a happy hubby for 37 years.
Congrats James
Author:  phil [ Sat Jul 04, 2009 9:25 am ]
Post subject:  Re: Help fitting neck
well james, seeing as you've hijacked your own thread, i'll also add my CONGRATULATIONS!!
i'm close to celebrating my 15th anniversary, and am sort of amazed at how well the whole guitar building / marriage analogy fits. the bits about the journey, about making new mistakes even though you've done the process before. the lessons you're learning while building guitars will be invaluable in your relationship - and i wish you many happy years of all of it!
phil
Author:  Shane Neifer [ Sat Jul 04, 2009 9:42 am ]
Post subject:  Re: Help fitting neck
Well James, you just got engaged our my wife and I's 10th anniversary! Although there are horses around us we ain't riding them!! Congrats and all the very best!

Shane
Author:  Pat Foster [ Sat Jul 04, 2009 10:03 am ]
Post subject:  Re: Help fitting neck
Congratulations, James! [clap]

Pat
Author:  Darryl Young [ Sat Jul 04, 2009 10:49 am ]
Post subject:  Re: Help fitting neck
All right James!!! Congratulations!

Was the horse riding something special for the engagement or do you regularly ride. We have a couple of horses and our girls ride at the playdays etc.
Author:  James Orr [ Mon Jul 06, 2009 12:58 pm ]
Post subject:  Re: Help fitting neck
It's time to get back on this today!

Thanks everyone! It was a great experience. I've been blown away by how excited people have been for us. The first of her friends we called started hyperventilating and crying . . . the first of MY friends we called said, "That's great! . . . So I guess I owe you ten bucks." Love the male/female contrast.

Darryl, it's a bit of both. I discovered riding when I took my mom and sister for Christmas two years ago. We did it again this year, and I just took Trish for the first time. It's the longest, most peaceful hour of the year. We ride along a river just a few miles south of Yosemite. I dream of having a horse someday!
Author:  Ziegenfuss [ Mon Jul 06, 2009 2:49 pm ]
Post subject:  Re: Help fitting neck
Congrats James!

I too got engaged on horseback (in the snow of an early Ohio winter)...
If you go riding on your honeymoon - learn from my mistake and don't assume that it is a good idea to ride a horse into the surf and then go on a 5 mile trot in your bathing suit - even if your new wife wants too!

Seriously, it is an incredible time,
Stephen
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