Hohner HG340. Structural issues
Hohner HG340
Welcome back my friends to the show that never ends, we're so glad you could attend, come inside, come inside........
This is my second, more in-depth look at this project Hohner HG340 repair I'd like to put out for replies. Gathering data on the neck joint has brought out multiple responses across the 7 platforms I've posted to. And I believe I have the information needed for its removal if it becomes necessary.
Quick review: The guitar was purchased back in 2010 and she was damaged and repaired sometime prior to 2010 and the repair was not aligned properly. The on line purchase gave no back history of the guitar or the repairs.
There was a loose gap under the X-brace on the treble side behind the X. The deepest tone bar was also loose. Both these I repaired with Titebond Original.
As she is now: The neck alignment in the vertical plane looks to be good. Touching the top of the bridge base. The left to right plane needs correction. These are based on no string tension applied. I wish I had taken a top deflection measurement before jumping into this while string tension was available. I got out of process and lost that opportunity.
There were three repaired cracks, one between the sound hole and the bridge. Two behind the bridge to the tail. All three look to be repaired with CA glue, back filled a little, no cleats inside under any of the three.
The previously poorly repaired crack along the bass side of the fingerboard had a gap and a snaggletooth point that stuck out into the sound hole. The gap (2-2.5mm) was backfilled with CA glue ( gel )? My guess is all the damage may have come from external compression to the top.
On the sound hole side of the transverse brace the top was cleated across the repaired crack. The transverse brace was loose from the top about at the centerline to across the gap about an inch.
The neck/edge of the heel on the bass side is compressed into the neck block, creating the off center line between the headstock and the center of the bridge. You can see the compression in the top binding. Internally I cannot fit a .002 feeler gauge in between the side and the neck block. Seems to be solid.
On the back, under the neck block, its footprint had come loose completely from the back. The back separation continued about 3' each side of center along the kerfing from the neck block. Here's where I think I made a mistake by re-gluing this area with Titebond Original at that time. I'm thinking now I went out of process and repaired this before it was needed to be done. And this may have limited movement for the crack repair.
Removed the cleat in front of the transverse brace from under the gap.
Reopened the poor repair along the fingerboard by using acetone and a Exacto knife.
WHAT HAPPENED NEXT WAS COMPLETELY UNEXPECTED. When the glue released in that crack, the gap expanded from about 2mm to 5mm. That repair was made under high tension.
Attempts to hand close that new 5mm gap is very hard to manipulate and immediately upon release the 5mm gap returns. I could flex by hand and move the gap, but it immediately returns to 5mm when released.
Clamping across the sides to try and close the gap is completely ineffective. No movement at all.
Next I went inside and released the bass side of the transverse brace all way to the rim. Then back to the across the centerline to the treble side sound hole brace. No change in flexing the gap closed. Once pressure is released the gap flexes back out to 5mm. Attempted to clamp across the gap again, no motion at all again.
At this point for about a month I flexed/ massaged and tried to loosen the "spring back tension" once or twice a day. Yesterday I must have exceeded the grain strength, and cracked the top again. This time under the fingerboard on the treble side. A hairline .2-.3mm gap that now is slightly open, enough to feel a point running a finger along the sound hole. This hasn't noticeably changed the gap on the bass side, or the pressure needed to hand closes the gap. But the gap does return back to almost 5mm.
Next I released the fingerboard extension from the top, back to the 14th fret. This did release some of the tension, and the gap closed to about 3mm at rest. Hand closing the gap is easier, but it still returns to 3mm at rest. But now I have instability on both sides of the fingerboard so less hand tension is probably advised from this point on.
I'm believing that all the years of misalignment and a unknown amount of time it may have sat un-stabilized has deformed possibly the sides or top.
It's a mystery to me. This is what I've done so far but I want more insights from the community.
My gut says take the neck off and fix the compression on the bass side. Correct the centerline from the neck to the bridge. Look at the neck block for issues. But I don't see how removal and re-alignment will alleviate the deformed tension in the body keeping the gaps open if that's what I truly see..
All ideas are welcome.
I've done the basic fingerboard edge crack repair 15-20 times before with good results. But I've never faced one with this deformity tension before.
DISCLAIMER: I'm a 60 year hobbyist, non professional. I normally only work on guitars I own. This is for my friend and my personal education. Yes, I'll grab unprofitable cadavers to work on since it's now a self sustaining retirement hobby.
.
Welcome back my friends to the show that never ends, we're so glad you could attend, come inside, come inside........
This is my second, more in-depth look at this project Hohner HG340 repair I'd like to put out for replies. Gathering data on the neck joint has brought out multiple responses across the 7 platforms I've posted to. And I believe I have the information needed for its removal if it becomes necessary.
Quick review: The guitar was purchased back in 2010 and she was damaged and repaired sometime prior to 2010 and the repair was not aligned properly. The on line purchase gave no back history of the guitar or the repairs.
There was a loose gap under the X-brace on the treble side behind the X. The deepest tone bar was also loose. Both these I repaired with Titebond Original.
As she is now: The neck alignment in the vertical plane looks to be good. Touching the top of the bridge base. The left to right plane needs correction. These are based on no string tension applied. I wish I had taken a top deflection measurement before jumping into this while string tension was available. I got out of process and lost that opportunity.
There were three repaired cracks, one between the sound hole and the bridge. Two behind the bridge to the tail. All three look to be repaired with CA glue, back filled a little, no cleats inside under any of the three.
The previously poorly repaired crack along the bass side of the fingerboard had a gap and a snaggletooth point that stuck out into the sound hole. The gap (2-2.5mm) was backfilled with CA glue ( gel )? My guess is all the damage may have come from external compression to the top.
On the sound hole side of the transverse brace the top was cleated across the repaired crack. The transverse brace was loose from the top about at the centerline to across the gap about an inch.
The neck/edge of the heel on the bass side is compressed into the neck block, creating the off center line between the headstock and the center of the bridge. You can see the compression in the top binding. Internally I cannot fit a .002 feeler gauge in between the side and the neck block. Seems to be solid.
On the back, under the neck block, its footprint had come loose completely from the back. The back separation continued about 3' each side of center along the kerfing from the neck block. Here's where I think I made a mistake by re-gluing this area with Titebond Original at that time. I'm thinking now I went out of process and repaired this before it was needed to be done. And this may have limited movement for the crack repair.
Removed the cleat in front of the transverse brace from under the gap.
Reopened the poor repair along the fingerboard by using acetone and a Exacto knife.
WHAT HAPPENED NEXT WAS COMPLETELY UNEXPECTED. When the glue released in that crack, the gap expanded from about 2mm to 5mm. That repair was made under high tension.
Attempts to hand close that new 5mm gap is very hard to manipulate and immediately upon release the 5mm gap returns. I could flex by hand and move the gap, but it immediately returns to 5mm when released.
Clamping across the sides to try and close the gap is completely ineffective. No movement at all.
Next I went inside and released the bass side of the transverse brace all way to the rim. Then back to the across the centerline to the treble side sound hole brace. No change in flexing the gap closed. Once pressure is released the gap flexes back out to 5mm. Attempted to clamp across the gap again, no motion at all again.
At this point for about a month I flexed/ massaged and tried to loosen the "spring back tension" once or twice a day. Yesterday I must have exceeded the grain strength, and cracked the top again. This time under the fingerboard on the treble side. A hairline .2-.3mm gap that now is slightly open, enough to feel a point running a finger along the sound hole. This hasn't noticeably changed the gap on the bass side, or the pressure needed to hand closes the gap. But the gap does return back to almost 5mm.
Next I released the fingerboard extension from the top, back to the 14th fret. This did release some of the tension, and the gap closed to about 3mm at rest. Hand closing the gap is easier, but it still returns to 3mm at rest. But now I have instability on both sides of the fingerboard so less hand tension is probably advised from this point on.
I'm believing that all the years of misalignment and a unknown amount of time it may have sat un-stabilized has deformed possibly the sides or top.
It's a mystery to me. This is what I've done so far but I want more insights from the community.
My gut says take the neck off and fix the compression on the bass side. Correct the centerline from the neck to the bridge. Look at the neck block for issues. But I don't see how removal and re-alignment will alleviate the deformed tension in the body keeping the gaps open if that's what I truly see..
All ideas are welcome.
I've done the basic fingerboard edge crack repair 15-20 times before with good results. But I've never faced one with this deformity tension before.
DISCLAIMER: I'm a 60 year hobbyist, non professional. I normally only work on guitars I own. This is for my friend and my personal education. Yes, I'll grab unprofitable cadavers to work on since it's now a self sustaining retirement hobby.
.
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