Hello everybody. My name is Bob Abernathy. I am a Roberto-venn graduate and i have stumbled across a exciting repair. A national reso. Needs neck reset and new(vintage) biscuit. This one is green paint with black trees yellow sun. Pinkish finish on FB. Only problem i am having trouble deciding on how to remedy is the neck relief.....way convex and no truss rod...... I don't want to use steam or heat so i don't damage finish on FB. Umm i thought maybe long flat aluminum block and c clamps or a re-fret attempting compression fretting which out of the 60 or so re-frets ive done none have been compression. PLEASE TELL ME SOMEONES GOT SOME ADVICE. Have a good one.
My rule of thumb in determining whether a compression refret ( using a wider tang fret to stiffen a neck) might be successful is- When you relax the string tension does the neck flatten out?
If so, then wider tang fretwire may well stiffen it up so that , under string tension, the neck will not forward bow as much. How much is unfortunately not , in my opinion, calculable in advance. I have never found that wider fret tangs will straighten a neck that maintains a forward bow even under no string tension.
In those cases heat bending sometimes works ( but can be a problem, or not possible, depending on the style of fretboard ), fretboard removal and regluing or replacement is sometimes necessary, but lastly- I have often, and had great success, doing a refret using “tall medium” fretwire such as Stew Mac’s #155 or Jescar’s FW50078 ( Jescar.com) in the center of most bowed area of the fretboard and shorter wire at either end. This does not remove the neck bow but does give a level plane for more comfortable fretting.
Steve nailed it : you have to determine wether the neck is too flexible or just bent. If flexible, compression refret or fretboard change or carbon fiber inlaying are solutions. If bent... then you can heat bend or plane the fingerboard or level the frets.
I can't thank you both enough. I believe i will remove the FB and use heat to get the neck back into shape. I discussed adding a truss rod with the customer and he seems happy with the idea. Again Thank you both so much for your input. I will post pics. Thanks again Fellas.
Hey Everybody. I have decided that i will see if the neck will hold relief under string tension without truss rod first to preserve the originality of instrument. But i have a extra question. The shims (in between the top of the neck bar and bottom of the inside of the body are glued on. as is the trapezoid block at joint. From what i can tell i need to remove these to obtain the new neck angle. or at least the two at the resonator hole. correct? Is it proper to glue them into place or are they held by tension? Any respons be will be greatly appreciated. Thanks again.
Hi Bob .. not sure if you've finished this project up yet. Re the shims at the 'mushrooms'. I don't believe National glued these, and what happens a lot is they shrink and fall out. Or, if glued, the hhg gave way and they fall out. A touch of hhg wouldn't hurt. Give Marc Schoenburger at National Guitar Repair a call if you want the final word on this.
Re neck bow..on a vintage National with that type fingerboard, you really want to preserve originality i.e. value, so a refret/leveling the board won't work. What works well for me is to remove the fingerboard and route two channels and epoxy in two carbon fiber rods (from Stu Mac). Glue them in while the neck is in a jig that will push it into the straight position. When you reglue the board, you won't see evidence of the work. Attached is a photo of one of mine. I'm able to lay a straight edge on the neck, and adjust the bolt until the neck is flat. Tom
put a raised nut on and play it as a slide