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| Slipped heels PSA http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=52270 |
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| Author: | DanKirkland [ Thu Aug 15, 2019 9:02 am ] |
| Post subject: | Slipped heels PSA |
Just a little PSA. I've been having quite a few (over 10) instruments from Martin and Gibson coming through the shop in the past 3 weeks that are suffering from slipped heels. For those that don't know, what I'm referring to is if you're sighting down the neck and right where the fingerboard meets the body there is a significant rise in the fingerboard where it should be either flat or have some relief in the form of a fallaway. It'll look like there's a valley in the fretboard at the 9-14 fret area. The most common denominator in each one of them is that they have been made within the last 5-15 years. Last ones I had on the bench for this problem were 04' J185, 15' J45 Vine, 14' 000-28, and a 17' D-41. They have varying degrees of the issue but it is very consistent. Each one of these had titebond/pva glue in the neck joint. Even had a Santa Cruz OM custom with a bad case come through. Santa Cruz is resolving that with the customer (great company btw). The fix is fairly straightforward, neck removal with shims added to the dovetail to help keep the neck seated better. Also regluing with hide glue vs. titebond. The hide glue so far has been a good fix. My suspicion is that the glue they used during that period creeps quite a bit and thus after a few years under tension the neck moves to the point where it needs a reset far too early. YMMV with how many you see, but don't be surprised if you see an increase of this problem as these guitars start to age a bit. |
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| Author: | doncaparker [ Thu Aug 15, 2019 9:56 am ] |
| Post subject: | Re: Slipped heels PSA |
Speculation: Do you think the manufacturers might also be failing to make the dovetail as snug a fit as it really ought to be? After all, glue creep only happens if the joint has somewhere to go. Again, that's just speculation. But if you rely on glue to keep the dovetail from moving around instead of the joint being tight, and if the glue you use has a tendency to creep when tugged on, I can see this happening with some frequency. |
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| Author: | B. Howard [ Thu Aug 15, 2019 11:49 am ] |
| Post subject: | Re: Slipped heels PSA |
Based on the makers you mention, I would need to see proof they didn't ship from the factory that way.... I don't think anything moved. I thinks it's poor construction and worse QC. |
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| Author: | Brad Goodman [ Thu Aug 15, 2019 1:44 pm ] |
| Post subject: | Re: Slipped heels PSA |
B. Howard wrote: Based on the makers you mention, I would need to see proof they didn't ship from the factory that way.... I don't think anything moved. I thinks it's poor construction and worse QC. Speaking to that , I was just in a large retail guitar store and was checking out a new Gibson J-200. The price was $5500. The action was 9/64" at the 12th fret bass side and the center seam on the back was off center by almost 3/8"! |
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| Author: | Woodie G [ Thu Aug 15, 2019 3:11 pm ] |
| Post subject: | Re: Slipped heels PSA |
Unless the neck block shows separation or actual movement, it sounds as though Mr. Howard is correct - this is a builder error in terms of controlling the extension geometry over the upper bout. Did any of the guitars show a separation between neck and heel (which would indicate a loose dovetail) or separation of the binding at the heel (which would indicate that the neck block is rotating/slipping? It is interesting to see the evolution of quality and workmanship issues at Martin, including periodic problems with bindings and finishes over the last 6 decades, a reduction in the nature and coverage of warranty work, and what we see as some concerns on the part of customers as to quality of warranty work coming back from the factory. |
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| Author: | Colin North [ Thu Aug 15, 2019 4:26 pm ] |
| Post subject: | Re: Slipped heels PSA |
Brad Goodman wrote: B. Howard wrote: Based on the makers you mention, I would need to see proof they didn't ship from the factory that way.... I don't think anything moved. I thinks it's poor construction and worse QC. Speaking to that , I was just in a large retail guitar store and was checking out a new Gibson J-200. The price was $5500. The action was 9/64" at the 12th fret bass side and the center seam on the back was off center by almost 3/8"!  Shame on them.
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| Author: | DanKirkland [ Thu Aug 15, 2019 6:33 pm ] |
| Post subject: | Re: Slipped heels PSA |
B. Howard wrote: Based on the makers you mention, I would need to see proof they didn't ship from the factory that way.... I don't think anything moved. I thinks it's poor construction and worse QC. That's a good point and is definitely possible. The 15' J45 I mentioned is one that we had sold through our shop. When it was here the action/projection was perfectly normal and within spec. It shifted drastically a little more than a year or so after the customer bought it, he could've been doing some things differently with humidity but it's pretty severe. That's doncaparker wrote: Speculation: Do you think the manufacturers might also be failing to make the dovetail as snug a fit as it really ought to be? After all, glue creep only happens if the joint has somewhere to go. Again, that's just speculation. But if you rely on glue to keep the dovetail from moving around instead of the joint being tight, and if the glue you use has a tendency to creep when tugged on, I can see this happening with some frequency. I think you're absolutely right about the lack of a snug fit. I will say that the Martin's I've fixed this on were better fit than the Gibsons. The Gibsons are definitely the rougher of the 2 overall. Woodie G wrote: Did any of the guitars show a separation between neck and heel (which would indicate a loose dovetail) or separation of the binding at the heel (which would indicate that the neck block is rotating/slipping? On all of these except for a GPCA4 that was in 3 months ago there was no visible separation. The J185 didn't even have cracked finish around the heel/sides to indicate wood separation. The J45 I mentioned earlier has no visible separation or cracks in the finish. That one is actually still at my shop. I could photograph it if you'd like? It's definitely the most severe example I can get pictures of. |
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| Author: | Clay S. [ Thu Aug 15, 2019 9:04 pm ] |
| Post subject: | Re: Slipped heels PSA |
Brad Goodman wrote: B. Howard wrote: Based on the makers you mention, I would need to see proof they didn't ship from the factory that way.... I don't think anything moved. I thinks it's poor construction and worse QC. Speaking to that , I was just in a large retail guitar store and was checking out a new Gibson J-200. The price was $5500. The action was 9/64" at the 12th fret bass side and the center seam on the back was off center by almost 3/8"! See! You don't have to be so fussy about putting these things together. 
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| Author: | SteveSmith [ Fri Aug 16, 2019 10:07 am ] |
| Post subject: | Re: Slipped heels PSA |
Clay S. wrote: Brad Goodman wrote: B. Howard wrote: Based on the makers you mention, I would need to see proof they didn't ship from the factory that way.... I don't think anything moved. I thinks it's poor construction and worse QC. Speaking to that , I was just in a large retail guitar store and was checking out a new Gibson J-200. The price was $5500. The action was 9/64" at the 12th fret bass side and the center seam on the back was off center by almost 3/8"! See! You don't have to be so fussy about putting these things together. Man, I need to up my prices 
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| Author: | bluescreek [ Fri Aug 16, 2019 7:04 pm ] |
| Post subject: | Re: Slipped heels PSA |
it most likely is RH I know Martin well and if the RH gets high there block will swell as they carry the grain same as the side. It is nothing new. Set them into a controlled environment for a week and they should settle back in. I had 2 this week that the customers were using humid pack in aug in pa. I set a hygrometer in the case that showed 70 % explained what was happening . Customer 1 reported that the hump has come down a good bit . Also on plywood blocks that transverse brace will make the top pop up when it is over humidified. After 20 years I still see this more regular than I would like. If you spend 1000 bucks on a guitar invest in a good hygrometer and know what the rh is in the case. |
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| Author: | Terence Kennedy [ Fri Aug 16, 2019 8:19 pm ] |
| Post subject: | Re: Slipped heels PSA |
I have seen more cases of over humidification in the guitars I have sold than the opposite. 70% in the case for sure. |
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