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| Can't get rid of gap at neck joint http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=29857 |
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| Author: | sprouseod [ Wed Nov 10, 2010 9:55 am ] |
| Post subject: | Can't get rid of gap at neck joint |
I am having difficulty with a gap on the treble side of the neck/heel joint. i have had to do a bit of flossing on the bass side to get the neck to line up with the center line, it subsequently looks very good, but the more I take the bass side down, the more there is a gap on the treble side. When I get the neck aligned I use a technique I learned from Frank Finocchio where I put a piece of double stick tape on both sides of the mortise on the body and push the heel back and forth on the sandpaper to take them down equally Any suggestions? Thanks Richard |
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| Author: | Michael.N. [ Wed Nov 10, 2010 10:40 am ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
What type of Neck joint? |
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| Author: | sprouseod [ Wed Nov 10, 2010 11:36 am ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
Bolt-on |
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| Author: | wolfsearcher [ Wed Nov 10, 2010 1:10 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
hello im not fimiliar with frank finocchinos method but did you take a look at john halls videos .. blues creek guitars dovetail neck setting its very through its the best neck set video ive seen on the web tomas |
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| Author: | SteveCourtright [ Wed Nov 10, 2010 1:28 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
Did you sufficiently relieve the face of the heel contacting the body? |
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| Author: | Daniel Minard [ Wed Nov 10, 2010 1:54 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
More than likely, the problem is that the side of the guitar at the heel joint area is not flat. To check it, lay a straight edge along the path where the edge of your heel lays & see if there are any gaps. If you can rock the straight edge, even a little bit, it'll really screw you up. I had this problem on my first parlour guitar. I sanded & sanded & drove myself half nuts trying to get it right. Finally, I sanded the sides with a 3" X 6" flat plywood sanding block & tried again. Took about 20 minutes to get everything fitting nice & tight. Instead of laying sandpaper down both sides of the mortise, try covering the whole area & then cut away the paper over the mortise. Take short strokes, so the bottom of the heel gets sanded evenly with the rest. Oh yeah... I know this seems silly, but... Make sure the tenon is not bottoming out on the bottom of the mortise. I like at least 1/16" clearance. Good luck! I know how frustrating this step can be. |
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| Author: | Pat Foster [ Wed Nov 10, 2010 3:34 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
Also, make sure you're not pulling up on the paper. DAMHIKT. Pat |
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| Author: | truckjohn [ Wed Nov 10, 2010 4:26 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
Richard, As Daniel points out -- if the sides of the guitar are not exactly flat -- sliding the neck up and down across the body could further hollow out a low spot and make a gap.... I might first try some chalk or sanding dust all over the inside of that neck heel/body joint to see where it is hitting... Could be just not enough clearance at the neck tenon where it meets the heel.... or not enough undercut on the heel itself.... The dust will tell you.... A thin 0.002" feeler gage is also super handy here -- you can stick it in and feel where it hits.... Do you remember the way that John Hall showed us how he flosses the neck joint at the SC get together? You carefully cut a thin piece of sandpaper and fit it between the neck and body with the grit facing the neck. Then, slowly pull it out from the bottom of the neck heel.... you can lightly snug up the neck with the neck bolts as you go.... I have done it this way now several times -- I use 80 grit sandpaper to start with.... The advantage is that if the side is not perfectly flat - flossing that joint will still make a nice tight joint.... it will shape the heel to conform to the body. Just gotta be careful that none of the grit makes marks outside the neck joint where they are visible..... Thanks John |
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| Author: | meddlingfool [ Wed Nov 10, 2010 4:35 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
One other thing that's caught me up once or twice. Not sure if it's painted or not but if it is make sure there are no ridges around the mortise. It can lift the paper and have it not be true to the sides. |
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| Author: | woody b [ Wed Nov 10, 2010 6:39 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
The bass side of the tenon is against the side of the mortise. |
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| Author: | Mike OMelia [ Wed Nov 10, 2010 8:00 pm ] |
| Post subject: | Can't get rid of gap at neck joint |
I decided I oversimplified my response |
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| Author: | Mike OMelia [ Wed Nov 10, 2010 9:09 pm ] |
| Post subject: | Can't get rid of gap at neck joint |
And I will restate. Keep the butt and neck blocks vertical. Use side spreaders and block spreaders to keep then as close to vertical as possible. Vertical to what? The top is a good reference. |
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| Author: | SimonF [ Wed Nov 10, 2010 9:50 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
This happened to me the other day - it took me a few minutes to figure out that the tenon had bottomed out in the mortise. As the others have said, there are a couple things you need to do to achieve a tight fit 1) Chisel a relief around the heel. You only need about 1/8" neck surface touching the body. This makes it faster to remove material and get a good fit quickly. 2) The headblock area needs to be perfectly flat from the top to the back. I find it essential to use flat sanding blocks with different grits attached. Best of Luck!!! |
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| Author: | Mike OMelia [ Wed Nov 10, 2010 11:36 pm ] |
| Post subject: | Can't get rid of gap at neck joint |
If you stop and think about it, you can end up with butt and neck blocks that are not parallel to each other. If you think about how this affects the nature of the joint surface at the neck block, all kinds of issues become apparent. I have been through this and I pay a lot of attention to getting these blocks parallel. |
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| Author: | TonyKarol [ Thu Nov 11, 2010 8:22 am ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
As afar as I am concerned, the neck/tail block interaction has nothing to do with fitting a neck .. a friend of mine builds more avante garde styled guitars, think wierd potato shape .. the blocks are both at wierd angles, and have nothing to do with each other. What is important is to have the mating surface flat from top to back - not side to side, unless you have flat shouldered shape. All my guitars have curved (side to side) shapes in the neck joint area, because I hate the flat look 9and as the guitar starts to fold up, it will look like its collapsed inwards - yechhh) ... and the neck can be made to fit fairly easily. |
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| Author: | sprouseod [ Thu Nov 11, 2010 9:49 am ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
I thinks things got turned around I am talking about the neck block/heel not neck block and tail block It looks like it is a combination of a slight hollow in the sides and I rolled the edge of the heel a little, But its not bottoming out there is about .080" of room. There is a bit of play in the mortise and tenon joint should that be shimmed to tighten it up? Let me make sure I understand the relationship. Mike you said the heel cheeks need to be parallel, that makes sense however one side may be slightly lower than the other, this would correct for the centerline alignment right? Todd Stock wrote: I guess I'm not tracking on the neck block/tail block thing. While I glue in the neck and tail blocks using the outside mold to control angle (vertical with regard to the plane of the top), once the body is closed, there is no interaction between the two that will affect the neck fit. Am I missing something?
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| Author: | SteveCourtright [ Thu Nov 11, 2010 10:32 am ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
The joint should be loose so the neck can respond when you try to change the neck angle. If the joint is tight, no amount of flossing will have any effect. |
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| Author: | sprouseod [ Thu Nov 11, 2010 10:36 am ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
makes sense |
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| Author: | Hupaand [ Thu Nov 11, 2010 4:15 pm ] |
| Post subject: | Re: Can't get rid of gap at neck joint |
I do necks mostly like that. It works best for me if the side, where the neck meets it, is perfectly flat from top to back. I sand it flat if it isn't. It also works best for me to do the joint sand by pulling the neck in only one direction. I tend to rock a curve into it if I go back and forth. |
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