1991 LP Standard measurements off: bad jig at factory?

Discussion in 'Gibson Les Pauls' started by lunchbox, Apr 14, 2013.

  1. lunchbox

    lunchbox Senior Member

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    I always noticed something was not right with the placement of hardware and pups on my guitar, and a lot others that I've seen. It's especially noticeable where the top knobs come close to the tailpiece. I decided to take some measurements and was really surprised how far off my guitar is. Below is a photo I marked colored lines showing where I took the measurements.

    [​IMG]

    Here's how she measures out:

    Tailpiece- red:4.75", green: 4.25"
    BPUP- black: 4-3/16", red: 3-5/8"
    NPUP- green: 2-3/16", yellow: 1-7/8"

    I'm kind of shocked. These measurements are waaaaaay off, and now it's really noticeable to me. I've seen quite a few guitars from around this period that are like this.

    Was this just a bad jig that they didn't fix for a long time or what? :wtf:
     
  2. joesatch

    joesatch Senior Member

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    this could potentially be devastating news.
     
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  3. lunchbox

    lunchbox Senior Member

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    I didn't realize that people from Florida could be so witty. My bad.
     
  4. joedonner2001

    joedonner2001 Senior Member

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    At least your neck pickup's pole pieces are dead center.

    :squint:

    But seriously - that's a pretty sweet-looking guitar you got there.
     
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  5. bosnialove

    bosnialove Senior Member

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    There's something wrong with your neck pickup. Kinda souspicious? I think the pole pieces need to be closer to the fretboard..
     
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  6. The Refugee

    The Refugee Senior Member

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    It's probably a humbucker sized P90 style pickup, like a GFS Dream 90 or a Seymour Duncan Phat Cat.
     
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  7. lunchbox

    lunchbox Senior Member

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    When I was first going to trade for this guitar there were a few people on this forum that said this might be a fake because the knobs were too close to the tailpiece. Now we know why: the whole set-up on the top is about 1/4"-1/2" off center. It seems that this is common for LP's of this era. Or is it?

    I was hoping more people could chime in regarding the same thing with their own gits, or offer some insight as to why Gibson let these go past QC back in '91.

    This site is great for compiling and sharing info about LP's. I'm contributing to that with what I've learned. Pretty simple really.
     
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  8. bosnialove

    bosnialove Senior Member

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    Just joking. :')
     
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  9. 77custom

    77custom Senior Member

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    We all know that Gibson's QC is off, so this shouldn't really surprise anyone who has been around the Gibson block. In the 70's they would call these "seconds".
     
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  10. theguitarpimp

    theguitarpimp Member

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    I worked there in 91, in fact-I was doing QC in the body and neck lines-as well as in the white wood machine dept (where the necks are fitted and the pickup cavities are routed; the knob and toggle holes, as well as the control routes were done at the body line)

    I can tell you EXACTLY what happened...The CNC in that department was brought in and set-up at the end of 89. From time to time there were problems in programming to locations on models we were transferring to CNC. I remember that guitars with pickguard mounted controls could be problematic as far as strings not lining up with pole pieces or having the routes not lne up with the neck (I believe that the X axis was the vertical one-it located off the center of the neck) These guitars were generally a big loss-they got found out in final assembly-near finished-lots of money in them and also many with the same problem in the line behind them. I remeber scrapping about 40 67 V reissues because of it. Painful deal-we had fixtures made to test them after that-leaving that up to the CNC operator was a mistake that had to be corrected at both points. We did just that.

    Your 91 looks like one that had a couple problems-but was one that ran on a Product Spec Deviation Form. This was a form that was submitted by QC to the plant manager if a deviation was found in any number of models in a run. If it was deemed minor (or not something that would effect the physical playability or ability to warrant the guitar-we QC folks tracked all down that fell into the parameters of the deviance-noted the lowest serial it was found on and the last serial unit to be corrected. If deviance from spec was too much-these guitars were destroyed. It was usually only a few guitars in any case. This guitar however, is one that has a deviation found in several hundred Les Pauls of various models in 1991. The CNC in the "back house" or body line right off the rough mill had some problems with one of the carve stations. These bodies were milled 4 at a time, and one station had a leak in an actuator air line that was causing the bodies to be slightly off when gripped by the pneumatic clamp. So, by the time we found it, many had been salted into all Les paul body blanks for a long period (1 in 4, basically). As you could imagine it was a very big scare!

    We worked to find all of them-and it was scary! keep in mind, this was a very hard to find malfunction-the moniters and guages on the CNC back there had not picked this up. And, with a blank body with no stoptail or pickup routes-this was impossible to see with the naked eye!

    We tested 3 of every model through to White Wood, stopping production on all Les Pauls for about 48 hours. After testing it was determined that, even though the knob holes/control pocket were off by a little bit-they were very consistently off, with only about 8% being too far out and requiring scrap tickets-these bodies were culled and immediately scrapped. Tool and Die were called in to make a temporary locating fixture for one of the White Wood CNC heads (that CNC also processed 4 guitars at once-all guitars were made in multiples of 4).This was very important because the entire neck/body assembly located from the treble tone knob hole, selector hole, and neck heel on Les Paul guitars. This allowed us to run the guitars with the deviance noted.

    So, while that's not the nicest thing that ever happened when we were getting used to CNCs it did not have a physical effect on the performance of the final product. In the yearly total of production Les Pauls of all models it was only about 800 guitars, not even a week's production.

    All this said-we made great strides during that period of years, and many (including myself) feel that the USA Gibsons of the late 80's,early 90's are some of the highest quality production Gibsons made in the Massman Drive plant from the change from Norlin ownership, until today.

    Sorry for the long post-it was a chore to write, but-being a person that was actually involved in this very issue, and having had to carry out what my superiors decided at that time-I feel it is important to share this information.

    Mark
     
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  11. HardCore Troubadour

    HardCore Troubadour Senior Member

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    Daaaaauuuuuummmmmnnn!

    Great explanation Mark...good to know, thank you.
     
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  12. Ayton

    Ayton Senior Member

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    Incredible insight, Mark. Thanks for being here.

    OP, your guitar has beautiful color and grain, and at least the strings, pole pieces, neck etc. all seem to line up? Don't be mad at it. :)
     
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  13. colchar

    colchar Banned

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    Fvck I love this place :thumb:
     
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  14. dspelman

    dspelman Senior Member

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    I think this is probably a Gibson copy of a Chinese fake.
     
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  15. lunchbox

    lunchbox Senior Member

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    THANKS MARK!!! That was EXACTLY what I was hoping to learn!! That is awesome, and understandable.

    I wasn't quite sure when Gibson changed over to CNC and thought at this point they might still have been routing by hand. But this explanation makes a lot of sense. Thanks for taking the time to type that out.

    :applause::dude:
     
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  16. GibsonMarshallGuy

    GibsonMarshallGuy Senior Member

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    I'd like to buy this guitar :)
     
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  17. crapthatsloud

    crapthatsloud Senior Member

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    What a neat thread. :)
     
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  18. lunchbox

    lunchbox Senior Member

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    That's really tempting because I just saw a '79 Standard blonde top all original for $1600 on CL this morning. :hmm:
     
  19. River

    River Senior Member

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    LB, is your bridge pickup a 490?
     
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  20. martin H

    martin H Senior Member

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    Great Information Mark; thanks. However, ...this thread is far too full of such useful, sensible and relevent information. Not in the MLP tradition at all.

    Time to start speculating that the placement of the hardware and pickups creates an "unbalanced body resonance" that either (a) sounds incredible, making these the 800 greatest Les Pauls ever made; or (b) has entirely the opposite effect; or (c) ask when the re-issue of the classic "91 off-center LP" is coming?
     
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