Presented for your consideration...............
I'm' looking at a mid 70's Japaneses made Hohner ( Teacup logo ) HG-512 12 string that is going to need a neck reset.
Anyone have any practical on hand experience with one and know what type of neck/body joint and glue they were made with?
This is NOT one of the better models that carry the badge "Hand made" inside the body. It has the metal base/plastic saddle with two thumb-wheel screw heads to set the height.
Like all my hobby projects, I just want to get her to play again and be structurally sound for another 20 years.
The only similar instrument I've seen was not a 12 string. It had three dowels through the neck block into the neck heel. I cut the neck off and turned it into a bolt-on.
Thanks for the response, can I ask a few defining questions here?
The Hohner you observed, was there separation between the heel and the body so that you could see or probe to determine a butt/dowel joint? Or did you have to cut the fingerboard off at the 14 fret and make the determination looking down at the joint?
It was a long time ago and I'm working with a bad memory here. I'd seen both a Hohner and an Epiphone built that way previously so I guessed at it and happened to be correct. I try not to spend any more time than I have to with these types of instruments and cutting the neck off is far easier than anything else. I use an electric bone saw. Taking your time it's about a 10 minute job.
I saw recently were a fingerboard was cut at the 12th fret (on a 14 fret neck join) to determine the neck joint. I haven't done it this way myself but the repairman said it helps the reconnect of the fingerboard extension line up better.
I've got a temporary wood insert and plastic saddle that duplicates the original in place. Once I get everything figured out I'll drop in a rosewood and bone combination with some options for adjustments to make for better intonation. I do have some work to do on the nut to drop the strings evenly across the bottom level of it's radius. That should give me a little lower action. I'm at full tension strings and feel I can ease the strings down a little more at the saddle. But I'm running out of saddle on the treble side. I've cut ramps since the pictures to increase the break angle.
Another possibility is that the difference in the top upward movement between no tension and full tension is about + .027. At that amount of rise, could a Bridge Doctor be used to hold the top in the no tension position and maybe put the neck reset off for a few more years?
I've done 6-7 bolt on conversions over the years, but always on six string guitars, and always to keep the guitar playable. I've often wondered if a 12 string would hold up.
Any insight on the Bridge Doctor option?
Even if it comes up short, and a reset is needed, it will keep the top from flexing as much over the years.
Thanks in advance.
In my opinion Bridge Doctors make for a good conversation piece. That's about it. I've seen one, installed zero. I know of no reason why a bolt-on conversion shouldn't work on a 12 string. I wouldn't be scared to do it at all. I've seen instruments with the fingerboard cut above the body joint but it seems to me you would lose a lot strength in that area and I would be reluctant to do it. Others may have more experience with it than I do.
Thanks for your time and insight on this.
This is what I'm looking for, opinion and insight.
The deed is done.
Consensus of my inquiries was a butt/dowel joint, and that what I found inside. 5 dowels, 2 directly under the fingerboard on each side of the truss rod, and 3 dead center down the heel.
First I did pull the 15th fret and drill/probe for a dovetail pocket. After getting through the fingerboard it only came up with a two tone sawdust, no feel of hitting a pocket. After the neck was off I found the reason for two tone sawdust. The neck block was made out of alternating laminate wood.
Good show John!