Official Luthiers Forum!

Solely owned and operated by Lance Kragenbrink
It is currently Thu Nov 14, 2019 1:55 am


All times are UTC - 5 hours





Post new topic Reply to topic  [ 4 posts ] 
Author Message
PostPosted: Wed Nov 07, 2018 6:01 pm 
Offline
Koa
Koa
User avatar

Joined: Wed Jan 14, 2009 3:14 am
Posts: 680
Location: Shefford, Québec
First name: Tim
Last Name: Mullin
City: Shefford
State: QC
Zip/Postal Code: J2M 1R5
Country: Canada
Focus: Build
Status: Professional
I found it was possible to obtain a couple of complete service sets of neck shims from Taylor, by satisfying them I was a legitimate repair business. So, I’ve been doing neck angle adjustments recently on Taylors, using factory shims — a heck of a lot easier than modifying or fabricating shims.

I thought I had their sizing system sorted out, based on the difference in thickness between the top and bottom of the heel shim, the fingerboard shim is always labelled 6 units greater (as every Taylor I’ve had apart to date had the same 6 unit difference between the two shims).

That’s been working well and I have a little spreadsheet that gets me pretty darn close on the first try ... up until today. I now have a 4-year-old 114 on the bench with a 12th fret action > 4 mm. The shims had the same 6 unit difference, but the largest heel shim in the service set, labelled 30, isn’t even close to adequately resetting the neck angle. The guitar certainly has significant belly, but no evidence of broken braces. I have enough saddle showing to lower the action to spec, but then the string height above the top will be lower than I’d like (10 mm or less).

Just wondered if anyone (especially someone Taylor-trained) had their shim system sorted out and could advise how they determine the correct shims to adjust angle?


Sent from my iPad using Tapatalk


Top
 Profile  
 
PostPosted: Wed Nov 07, 2018 7:50 pm 
Offline
Koa
Koa

Joined: Wed Feb 17, 2016 8:54 am
Posts: 544
State: Texas
Country: United States
Focus: Repair
I've been a taylor cert'd dude for a while now.

So you're use a 30 on the heel, which I can assume you've matched with a 24 on the fingerboard extension. I'll be honest there are guitars where the regular logic need not apply because of tension/movement in the wood that only exposes itself over time. What I've done is basically trial and error it until I get a match where I want it to be, on a few of the older ones with the shim system I've made thicker shims because the required angle was more than the factory shims could provide.

All that being said, it sounds like something else is up with the guitar along with the shim issue. 4mm is high. How bad is the belly?



These users thanked the author DanKirkland for the post: Tim Mullin (Fri Nov 09, 2018 3:26 pm)
Top
 Profile  
 
PostPosted: Thu Nov 08, 2018 8:25 am 
Offline
Cocobolo
Cocobolo
User avatar

Joined: Tue May 15, 2012 7:42 am
Posts: 115
First name: Craig
Last Name: Gordon
City: Buffalo
State: NY
Zip/Postal Code: 14216
Country: USA
Focus: Build
Status: Professional
I had a guitar on the bench with a similar problem. While the instrument didn't obviously exhibit signs of over humidification, whe placed in its case for 24 hrs with a humidity reader it turned out tobe at 65%!
Dehumidify to bring it diwn to at least 45% and then re check. If still problematic, Taylor will reshape the pocket if the guitar is under warranty



These users thanked the author CraigG for the post: Tim Mullin (Fri Nov 09, 2018 3:26 pm)
Top
 Profile  
 
PostPosted: Fri Nov 09, 2018 3:44 pm 
Offline
Koa
Koa
User avatar

Joined: Wed Jan 14, 2009 3:14 am
Posts: 680
Location: Shefford, Québec
First name: Tim
Last Name: Mullin
City: Shefford
State: QC
Zip/Postal Code: J2M 1R5
Country: Canada
Focus: Build
Status: Professional
Thanks for the ideas, guys. Much appreciated.

Another check of the bracing confirmed everything was tight. I checked with the owner who confirmed that his home is « very humid ». That’s very unusual in this area, where the common problem is low humidity during the heating season.

Swapping standard shims got me ~0.5 mm. Then sitting in my shop the belly appears less prominent and we seem to have achieved another 0.5mm, so humidity seems a contributing factor. I suspect hysteresis while spending 4 years with a swollen belly has caused permanent distortion, so I don’t expect it will correct itself just under drier conditions, and the owner is not likely to change houses.

So, my plan now is to remove some material from the bottom of the heel shim, hoping to get another ~0.5 mm through neck angle, then find the rest at the saddle, leaving some room for adjustment either way.



Sent from my iPhone using Tapatalk


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group
phpBB customization services by 2by2host.com