Mid 1960's Harmony H1270 - Neck Reset+

DAY 2 – Sanded the fretboard area on the top. Sanded the dovetails & fit the neck back into the pocket. Removed the bass side tuners. The holes in the headstock are 1/4", clearance for .218" shafts, but the .235” Stew Mac shafts won’t go in. Check the center distances of the old & new tuners. I will have to possibly slightly open the holes for the shafts in the headstock, no going back. Loosened the truss rod nut to somewhat level the neck. The fretboard radius is a mess!! I'm guessing it's 10", but most of it is rolled over about ½” from the edges, and the fretboard extension area is 7" or 8"!! I might have to pull all the frets and sand the fretboard to 10"!! It has a bound fretboard, I'll have to cut everyone to length!! NOPE!! The fretboard extension is low, I won't be levelling that area. Level to 10" radius and see what it looks like. Heated the nut to loosen the glue, tapped it with a 10" radius block & hammer a few times, and pried it out. I know from previous experience the gooey glue they used to hold the nut & saddle in will not allow them to be tapped/pulled out without heating them to soften the glue, otherwise they will come out in pieces. There are cracks in the fretboard extension area of the top, at the edges of the unfinished area. I don’t want that to get any worse, so I used fish glue to attach a .20" x 1-3/4" x 5" pine/spruce brace under the FB extension. I designed, detailed & made an STL to 3D print a H1270 Nut Slotting Block (CSG, .070" constant gap between pairs, E strings .100” from the edge).

Cracks in the top under the fretboard.  If the fretboard splits on both sides the fretboard and neck block will pivot down and forward, making a real mess.




So I used fish glue to attach a .20" x 1-3/4" x 5" pine/spruce brace under the FB extension.


A wax paper covered (don't want it to stick!!) caul to hold the brace tightly in place while the glue dries.






It's a little crooked and off center, but it will work.

DAY 4 – I compared the tuner outer shaft center distances for the old & new tuners to find they are the same. BUT, the holes centers in the headstock are about .03" SHORTER!! That's why the tuners went in bowed and why the new ones won't fit. I opened the holes in the drill press in small steps, from .250 to .262, to .272 & .281. They might still be a little tight but they go in. AND, the 2 inner mounting screws line up and the outer holes are a half diameter off!! So close!! I plugged the outer holes with toothpicks & superglue. Then I mounted the new tuners, drilling the outer holes with a 5/64" drill and using the old smaller/longer screws.

Drilled open the tuner shaft holes in 3 small steps.


Plugged the outer tuner mounting screw holes with the tapered end of a toothpick and superglue.


I need to take a pic of the tuners mounted.

DAY 6 – This is documented as a day later but it is actually 16 days later. I’ve had other projects to work on.

Finally getting back to this, I made the 2 saddles.

I designed a 3D printed file guide to have a constant gap between the string pairs, and a constant string gap between the string sets.


Marked the depth.


Filed to the marks.


DONE!!

DAY 8 – Installed the tailpiece. Put tape on the body next to the heel area and scraped the small lacquer radius. Undercut the heel. Taped the floating bridge to the top in the old shadow. The neck projects .16" below the top of the bridge. Set the tape on the heel at .07", filed & sanded to the tape. The neck is centered. The neck now projects .12" above the bridge. Installed the strings in the tailpiece. Undercut the heel more.

Installed the strings in the tailpiece.


Undercut the heel.

DAY 10 – The action is 3/16" low E & 11/64" high E. Sanded .015" off the bottom of the nut, sanded the top of the bass side, and deepened the slots slightly. Added (2) .022" shims under the rear saddle. Set the tape on the heel at .06", filed & sanded to the tape. Tuned to C#. The neck relief is zero. The nut action is close. The action is a little over 5/64" low E & 5/64" high E. The neck is off center .08", need to take material off the treble side. Undercut the heel more and filed the whole treble side of the heel. Restrung & tuned approx to C#. Loosen the TR nut and there's still nearly zero neck relief. The neck centering is better. The action is still a little over 5/64" low E & 5/64" high E. Leave it and check it again tomorrow.

The action is just about there.


I put tape on the strings near the tailpiece so they don't shift backwards.  During a normal neck reset I pull the bridge pins and remove the strings.  I can't do that here.  The neck is disconnected at the heel but still connected by the strings.  When doing anything to the heel (moving the tape, filing, sanding, deepening the undercut, etc.) I have to be aware and control both the body and the neck so the don't get dropped or damaged.


This was an attempt to show the strings are centered but I didn't realize I got the picture angle wrong.

DAY 12 - (The next day) - Unclamped from the neck jig.  There is a .005"/.010" heel gap!  This seems to happen on almost ALL Harmony's.  The neck is clamped with A LOT of force!!  HOW can the neck joint overcome that pressure and end up with a gap??  It isn't there an hour after I clamp it!

Day 13 - (1 week later) - Tuned to C#. The nut action is good. The neck relief is good. The action is a little under 5/64" low E & a little over 1/16" high E.

DAY 14 - (6 months later) - Tuned to C#, the nut action is good, the neck relief is good, the action is a little under 3/32" both E's. There is a .012" heel gap!!! It's been tuned to for 6 months, I doubt it's going to get any worse. Remove the neck and do it again or fill the gap??? 

DAY 15 (2 days later) – I have better idea. Pull the 13th fret, drill the (2) 1/16" holes with the drill jig, use the 1mm heat sticks to soften the neck joint glue, remove the heat sticks, clamp the heel flush, let it harden overnight. I can't clamp the heel while heating because the holes should intersect dovetail surfaces, any movement would pinch the heat sticks resulting in them getting stuck and probably damaged pulling them out.

DAY 16 (5 weeks later) - Amazingly it is still tuned to C#!! The action is a little over 3/32" low C# and 7/64" high C#. The heel gap is .015". The neck relief is a little high.  How is it continuing the very slowly get a little worse??  Yet the tuning has never changed??

DAY 17 (3 weeks later) – FINALLY GETTING THIS DONE!!  Loosened the strings, wrapped the ends of a rubber band around the two groups of strings and held them back with a keychain carabiner. Used the soldering iron to heat the 13th fret and removed it with the Stew Mac fret pliers. Used the drill jig, clamped to the top with a large spring clamp, and drilled (2) 1/16" holes 4 inches deep, definitely hitting the old holes. Put the 1mm heat sticks in the holes for 30 minutes, swapping them after 20 minutes. The outside of the heel wasn't real hot, I wanted to be sure the joint was hot enough to soften the fish glue. Removed the heat sticks with the pliers (important!!) and easily clamped the heel tight to the body!! Leave it clamped overnight to fully harden.

Loosened the strings and pulled them back.  Soldering iron and fret removal pliers ready to go.




Removed the 13th fret and clamped the drill jig to the fretboard.




Heat sticks in!




Th heel clamped easily!!!