Saddle compenstion, Gibson LG-1

If you have a string instrument of any kind that needs fixing, a mistake you made in building a new instrument that you need to "disappear," or a question about the ethics of altering an older instrument, ask here. Please note that it will be much easier for us to help you decide on the best repair method if you post some pictures of the problem.

Saddle compenstion, Gibson LG-1

Postby Matt Atkinson » Tue Apr 16, 2019 11:08 am

Hi all, It's been a very long time since I posted anything here! Hope to hang around more for a while...

I have finished re-bracing a little LG-1 that my brother in-law was kind enough to give me. I was just going to fix a loose back brace but decided to x-brace the top as well. Pulled the back, braced and did a little cheater neck reset when gluing the back on again. Anyway, someone previously replaced the plastic bolt on bridge with rosewood and did a spectacularly lousy job so I have removed the bridge and will make a new one slightly larger to cover the gouged-in pencil marks left by the last guy :( Looking for numbers for saddle compensation to cut a new slot. I'm planning on using my saddlematic to locate, just wanting the correct adjustment info if anyone knows what's best. Thanks in advance!
Matt Atkinson
 
Posts: 9
Joined: Fri Apr 18, 2014 2:35 pm
Location: Massachusetts

Re: Saddle compenstion, Gibson LG-1

Postby Barry Daniels » Tue Apr 16, 2019 11:11 am

Cumpiano's book states that you should add 0.15" to the scale length at the middle of the saddle.
MIMF Staff
Barry Daniels
 
Posts: 2104
Joined: Thu Jan 05, 2012 10:58 am
Location: The Woodlands, Texas

Re: Saddle compenstion, Gibson LG-1

Postby Bryan Bear » Tue Apr 16, 2019 11:35 am

I Stew Mac's fret position calculator (which is what I use to estimate how much compensation to build in) gives 24.836" for the treble e and 24.958" for the bass e using 24.75" as the nominal scale length. That would be an extra 0.086" on the treble side and and extra 0.208" on the bass side. That would average and extra 0.147" so right in line with the Cumpiano number Barry provided above. The Stew Mac calculator lists +or- 0.03" for compensation; 0.15 to 0.147 is a tenth of that margin. . .

Depending on what your scale length is (I was guessing at 24.75") the compensation will change a little bit. But, these are estimates to get you in the ballpark for final adjustment. If you plug in the values for martin short scale and long scale the difference is 0.002" treble side and 0.004" bass side. I can't reliably measure that closely on my shop made saddle-maticesque tool so I never really change the compensation unless I am using it for a drastically different scale.
PMoMC

Take care of your feet and your feet will take care of you.
User avatar
Bryan Bear
 
Posts: 1118
Joined: Fri Jan 06, 2012 1:05 pm
Location: St. Louis, MO

Re: Saddle compenstion, Gibson LG-1

Postby Brian Evans » Tue Apr 16, 2019 12:07 pm

This is the calculator that I use, I find it extremely accurate and takes a lot of different factors into account: https://www.liutaiomottola.com/formulae ... sation.htm

I actually use more than a few of the calculators and webpages that he has there, it's a great site.

Edit: I just read this scholarly article, linked from the above site: https://osf.io/bqzf4/ I not only understand nut compensation for the first time, he made it make intuitive sense, plus it shows that fussing obsessively with compensation is a losing game because in blind testing even expert players and luthiers can't tell the difference to a degree that matters. Neat experiment.
Brian Evans
 
Posts: 773
Joined: Sat Aug 30, 2014 8:26 am
Location: Tatamagouche, Nova Scotia

Re: Saddle compenstion, Gibson LG-1

Postby Matt Atkinson » Fri Apr 19, 2019 12:03 pm

Thanks all. Scale is actually 24.625. I guess these little Gibsons were all over the place. Pretty sure the previous bridge replacement was a stock, pre-slotted version. Seems the repairer just placed it with the existing bridge pin holes. Slot is way off. The back of the slot is where the front should be. Freaked me out a little until I thought about it and triple checked my math. It's funny the only other guitar I've done work like this on was a mid 70s D35 and that saddle was 3/16 too far forward. Is it just my luck? :shock:
Matt Atkinson
 
Posts: 9
Joined: Fri Apr 18, 2014 2:35 pm
Location: Massachusetts

Re: Saddle compenstion, Gibson LG-1

Postby Barry Daniels » Fri Apr 19, 2019 12:22 pm

That is fairly common.
MIMF Staff
Barry Daniels
 
Posts: 2104
Joined: Thu Jan 05, 2012 10:58 am
Location: The Woodlands, Texas

Re: Saddle compenstion, Gibson LG-1

Postby Freeman Keller » Sat Apr 20, 2019 12:11 pm

I replaced the plastic saddle on an LG-1 with a rosewood one and cut the slot at the scale length plus 1/16 on the high E and scale length plus 3/16 on the low E. I gave the saddle the usual B string notch and the intonation seems pretty good on this funky old guitar. Also had to reinforce the bridge plate and top which were pretty badly damaged, plug some holes, remove finish under the bridge footprint - the usual stuff

IMG_4732-1.jpg


IMG_4785.JPG


IMG_4788.JPG


And yes, there are a whole generation of Martins from the 70's with the saddles in the wrong place. And of course the dilemma of what to do about them
Freeman Keller
 
Posts: 379
Joined: Mon Feb 27, 2012 11:34 am

Re: Saddle compenstion, Gibson LG-1

Postby Chuck Tweedy » Mon Apr 22, 2019 10:09 am

Hey Matt! Good to see you.
Likes to drink Rosewood Juice
Chuck Tweedy
 
Posts: 1050
Joined: Fri Jan 06, 2012 6:25 pm
Location: San Diego, CA

Re: Saddle compenstion, Gibson LG-1

Postby Matt Atkinson » Thu Apr 25, 2019 11:18 am

Hi Chuck!
Matt Atkinson
 
Posts: 9
Joined: Fri Apr 18, 2014 2:35 pm
Location: Massachusetts


Return to String Instrument Repair: Practical and Political Issues

Who is online

Users browsing this forum: No registered users and 4 guests

Your purchase from these sites helps support the MIMForum, but only if you start at the links below!!!
Amazon music     Amazon books     Amazon tools     Rockler tools     Office Depot    

The MIMF is a member-supported forum, please consider supporting us with a donation, thanks!
 • Book store • Tool store • Links •