PDA

View Full Version : Neck joint flossing?



Steve-atl
01-13-2019, 06:49 AM
Can you really get a good neck joint by the "flossing" technique?

I am putting together a Stewmac baritone kit.

There is a slight radius at the neck joint area, so the neck is high in the center. I have been working at this all morning and I am not sure am getting closer to a good neck joint. I think the problem is it's hard to hold the neck strait while pulling the sandpaper out. If the neck rocks then you are just acerbating the problem.

Any suggestions are appreciated

Thank you

doug powdrill
01-13-2019, 07:25 AM
I use a dremel and sanding drum to take out material from the center of the heel, then you're basically flossing the edges...much easier and still a good joint...hope this helps.

Michael Smith
01-13-2019, 07:27 AM
I'm not sure what kind of joint the Stewmac kit uses. It looks like it's just butts? Couple things you might try. Flatten the offending area with a block of wood and sand paper on the body. And Or Use some self stick paper of about 100 grit on the body then place both heals of your hands on the body and move the neck back and forth in very small strokes. If you have a disk sander you can use that to flatten both pieces. BUT DON'T TURN IT ON. just rotate by hand. Also if you relieve the heel that will help though if you don't yet have the skills or tools to do that you might make a mess of it. Flossing as your doing does work but it is difficult without relief.

Steve-atl
01-13-2019, 07:40 AM
Thanks, Doug, good idea

Steve-atl
01-13-2019, 07:47 AM
I made sure the center line was flat but it starts to bent before the with of the nick. The sides are laminated. I sure I would sand through before all of the areas was flat

Yes it's a butt joint with two dowels

Thanks

Allen
01-13-2019, 09:15 AM
If this is a bolt joint you also want to undercut the area on the neck so that the only area you need to be flossing is the outer 3mm or so that make contact with the body. It will go so much faster for you then.

jcalkin
01-13-2019, 09:59 AM
If you are confident that you can drill straight holes for the dowels just drill the lower one right through the body for a bolt hole. One bolt is enough, skip the top hole. Hollow out the heel joint to make it sit nicely on the body. The top of the hollow will be hidden by the fretboard and the bottom by a nicely fit heel cap. Once it looks like the center line of the neck will sit on the center line of the body, epoxy a piece of threaded rod into the heel that reaches deep enough into the body to attach a nut. Drilling straight holes should be the hardest part of the equation, but that would be just as important if you used the dowels. If StewMac used their funky neck block try to have the bolt hole come out in the center of it.

DPO
01-13-2019, 10:06 AM
If you are confident that you can drill straight holes for the dowels just drill the lower one right through the body for a bolt hole. One bolt is enough, skip the top hole. Hollow out the heel joint to make it sit nicely on the body. The top of the hollow will be hidden by the fretboard and the bottom by a nicely fit heel cap. Once it looks like the center line of the neck will sit on the center line of the body, epoxy a piece of threaded rod into the heel that reaches deep enough into the body to attach a nut. Drilling straight holes should be the hardest part of the equation, but that would be just as important if you used the dowels. If StewMac used their funky neck block try to have the bolt hole come out in the center of it.

Or just use a lag bolt.

Steve-atl
01-13-2019, 10:11 AM
. Drilling straight holes should be the hardest part of the equation, but that would be just as important if you used the dowels. If StewMac used their funky neck block try to have the bolt hole come out in the center of it.

Thanks, John that's a good idea. I have a drill press so drilling straight holes is not a problem. I might give that a go.

sequoia
01-13-2019, 04:18 PM
I use a dremel and sanding drum to take out material from the center of the heel, then you're basically flossing the edges...much easier and still a good joint...hope this helps.

I do this too sometimes with dremel and small sanding drum. However, since the sides are perfect and plumb on the neck heel, they are sacred and not touched. Only the middle out to within a couple of mils to the edge. Another little thing I do is identify the area that is hanging things up slightly is to put chalk on the body and carefully butt the neck up to the body. Chalk mark shows where contact is being made. I'm talking radiused neck/body joints here not flat joins which are basically a piece of cake.

SpaceForRent
01-14-2019, 08:08 AM
If you are confident that you can drill straight holes for the dowels just drill the lower one right through the body for a bolt hole. One bolt is enough, skip the top hole. Hollow out the heel joint to make it sit nicely on the body. The top of the hollow will be hidden by the fretboard and the bottom by a nicely fit heel cap. Once it looks like the center line of the neck will sit on the center line of the body, epoxy a piece of threaded rod into the heel that reaches deep enough into the body to attach a nut. Drilling straight holes should be the hardest part of the equation, but that would be just as important if you used the dowels. If StewMac used their funky neck block try to have the bolt hole come out in the center of it.

Do you have any photos of this process? I think I understand what you're talking about, but am not 100% sure. It may be something I want to apply to my own build.

sequoia
01-14-2019, 08:34 AM
Drilling straight holes in a neck heel/neck block can be a challenge. At least for me. I've never figured out a way to use my drill press because of the geometry of the neck. What I do is use my electric DeWalt drill that has bubble levels built into it for vertical and horizontal level. Put the neck in a vise, level it, then drill the hole(s) while carefully leveling the bubbles in the bubble levels. Not perfect of coarse, but can get pretty close. I then use dowel pins to line up the placement of the holes for the neck block. What you DO NOT want to do is drill completely through your neck heel as that would be a TFD of the first order. Use a drill stop to prevent this. Good luck.

Timbuck
01-14-2019, 11:21 AM
It ant easy to get the perfect joint, especially with the compound dovetail on a radious end..but I find that if you get the body end right first ..then do all the work on the neck end and don't touch the body area anymore..and when you have got the joint looking good ..it's then that you find the neck is off centre and the fretboard angle is all wrong:( and you have to start again :)

printer2
01-14-2019, 02:07 PM
Might help sticking packing tape on the back of the sandpaper to reduce friction. Other than that a second set of hands.

Jardin
01-15-2019, 01:08 PM
I figured I would try to send you a description and some pictures of a rig I set up just for this type of operation....by no means is this new or novel just something to help hold the body and neck in the right place while flossing repeatedly until the fit is right..... Again like others have said do yourself a favor and relive the area in the middle so that you really are only flossing the outer edges of the neck as that is what matters. I create this relief with a chisel so nothing high tech there....

So the contraption is simple and should be self-explanatory....But basically you clamp the body down on the center-line...The neck gets double stick taped to the plastic (on center) and this plastic slips in to a channel I routed in the base so that it holds true to the center-line of the body.... The plexiglass/plastic has a scribe center-line so that I could easily see that it matches up with the one I drew on the baseboard. If you make one make sure it fits snug with no play side to side otherwise you are wasting your time.

By the way: after looking at the picture the center-line looks off but is just the angles of the photo. I

Hope this helps!
114806
114807

printer2
01-15-2019, 01:17 PM
I figured I would try to send you a description and some pictures of a rig I set up just for this type of operation....by no means is this new or novel just something to help hold the body and neck in the right place while flossing repeatedly until the fit is right..... Again like others have said do yourself a favor and relive the area in the middle so that you really are only flossing the outer edges of the neck as that is what matters. I create this relief with a chisel so nothing high tech there....

So the contraption is simple and should be self-explanatory....But basically you clamp the body down on the center-line...The neck gets double stick taped to the plastic (on center) and this plastic slips in to a channel I routed in the base so that it holds true to the center-line of the body.... The plexiglass/plastic has a scribe center-line so that I could easily see that it matches up with the one I drew on the baseboard. If you make one make sure it fits snug with no play side to side otherwise you are wasting your time.

By the way: after looking at the picture the center-line looks off but is just the angles of the photo. I

Hope this helps!
114806
114807

Ok, but you do not show the spring pulling the neck to the body or the cable going to the foot pedal counteracting the spring which pulls the neck away from the body. ;)

Timbuck
01-15-2019, 09:49 PM
Perhaps you could make a simple version of this set up... since this video I have made an improved model that I now use all the time.

https://www.youtube.com/watch?v=rA7o-8Osz0Q

tparse
01-15-2019, 10:00 PM
I have tried the flossing and making the sides flat at the neck. I didn't like any of them. I like the curve of the top to go into the neck. These are old pics and I have refined the tool quite a bit but you get the idea. The body and neck are indexed with the jig so body and neck are aligned. I get a great fit in less than a minute.114815114816114817

printer2
01-16-2019, 03:10 AM
Perhaps you could make a simple version of this set up... since this video I have made an improved model that I now use all the time.

https://www.youtube.com/watch?v=rA7o-8Osz0Q

How could you possibly make it better?

Timbuck
01-16-2019, 05:01 AM
How could you possibly make it better?

I made the next one out of steel .... and made it more accurate :)..I was thinking of adding a motor and giving it an oscillating action. (maybe one day)

Steve-atl
01-16-2019, 10:06 AM
Might help sticking packing tape on the back of the sandpaper to reduce friction. Other than that a second set of hands.

Yes I did the packing tape trick it helped a lot

Steve-atl
01-16-2019, 10:12 AM
Wow, I am so glad someone else's shop looks like that. Thank you

I guess you double-side tape the sandpaper to the inside of the block

Steve-atl
01-16-2019, 10:16 AM
I have tried the flossing and making the sides flat at the neck. I didn't like any of them. I like the curve of the top to go into the neck. These are old pics and I have refined the tool quite a bit but you get the idea. The body and neck are indexed with the jig so body and neck are aligned. I get a great fit in less than a minute.114815114816114817

Did you make that out of an old band saw? Thats awesome

tparse
01-16-2019, 12:23 PM
Yes it is from an old bandsaw. The biggest problem was finding the correct sandpaper (it has to be really wimpy) and learning how to make my own belts. The trick is to completely remove all sanding grit where the ends overlap and using 5 minute epoxy which never really gets hard or brittle.