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  1. #1

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    Check out the fit of these braces to the underside of the top. This is one of the P90 equipped 275 guitars that's been sitting in the case - brand new. Just got the back off this morning. Oh boy.

    .Unfortunate top brace fitting in new Gibson ES-275-2759-jpg
    Unfortunate top brace fitting in new Gibson ES-275-2757-jpg
    Unfortunate top brace fitting in new Gibson ES-275-27510-jpg

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  3. #2

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    Yeah it looks like it's put together a bit too casually for a guitar in it's price range.
    Tone bars are kerfed so they don't have to shape them to exact fit. But then they didn't bother gluing them all the way

  4. #3

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    Wow. Looks like the tail block isn't really glued to the top either. Amazing what Gibson can get away with because they're Gibson.

    Just out of curiosity, how did you end up taking the back off a brand new guitar?

  5. #4

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    I ended up buying this guitar for a pretty reasonable price as a project, thinking I could get in the F holes with clamps and glue the braces back. Not sure what I was thinking as there's big chunks of dried superglue between the ends of the open braces and the top. So I'm the second owner, no warranty at this point and the only way this is going to get fixed is if someone opens it up. Might as well be me. So I used a router to cut most of the binding off, took the rest off by hand then got a knife around the joint. That wasn't bad but the neck block was a bit tougher. As has been pointed out the tailblock was making little contact with the back, but there's good contact everywhere else. Maybe I'll glue an extension on the short tailblock and chalk fit it in. The kerfed lining is pretty much intact so after the braces are replaced with nice fitting ones I'm going to try and leave the kerfed lining alone without much cleanup that may alter the fit, and try to glue the back on in the same exact position it was. The 275's with the p90's seem to be priced at around $3500, crazy money for this level of quality control IMO although the rest of it looks ok.
    Unfortunate top brace fitting in new Gibson ES-275-2755-jpg
    Unfortunate top brace fitting in new Gibson ES-275-2754-jpg
    Unfortunate top brace fitting in new Gibson ES-275-2752-jpg
    Last edited by vejesse; 08-02-2019 at 11:46 AM.

  6. #5

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    Looks like you've done really nice, clean work so far. It should be a rock animal when you're done. Add $500 to whatever Gibson's charging for 'em (don't you wish?). That's a laminate top, right? Funny that they use curly maple veneer on the inside of the top, but not the bottom where you can see it.

  7. #6

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    That restores my faith at buying new gibsons, specially unseen..

  8. #7

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    It is like sausages and burger patties; love them but don't ever try to find out how they're made.

    Now that I know I can't unknow. Puts a dampener on my enthusiasm. It will be a far better guitar once you're done with fitting your own tonebars to the top.

    That's pretty crazy putting curly maple veneer on the underside where it cannot be seen than on the back where it can be seen. And you are still paying for it.
    Last edited by Jabberwocky; 07-22-2019 at 03:30 AM. Reason: I hate this Autocorrect shirt!!!

  9. #8

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    ...The builders may not even know the difference between the top and the bottom or the inside and outside.

  10. #9

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    ...because the guitar ain't worth much. This is beyond embarrassing. It looks like they're not even trying. This needs to be shared widely to warn the fools out there that Gibson is wholly uncommitted to making a good instrument.

    You should send the link to this forum thread to the president of Gibson. Hah! They should pay you the price of the guitar to kill the thread for the damage it could do to their reputation. Good luck with your improvement effort. I guarantee that the guitar will not be worse than before.

    Thanks for posting.

  11. #10

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    Omfg... this is really upsetting..... my €250 Ibanez looked waaaay better inside!

    Here's what you get for $3200 less:





    Here's the only little flaw I could discover. Some squeeze-out of the glue.


  12. #11

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    Mirror exam on my ES-275 looks fine. But I got it new and checked it out thoroughly right away. I learned to do that by experience. You've documented the possible shoddy workmanship elegantly with your pics. Thanks.

    This is really shameful workmanship.

  13. #12

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    Quote Originally Posted by vejesse
    Check out the fit of these braces to the underside of the top. This is one of the P90 equipped 275 guitars that's been sitting in the case - brand new. Just got the back off this morning. Oh boy.

    .
    Unfortunate top brace fitting in new Gibson ES-275-27510-jpg
    Only a Gibson is good enough ....

    man what a guitar !

  14. #13

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    Any archtop builders care to critique the bracing scheme? Towards the lower end I was able to get a brace tap tone very close to the same note as compared to right next to the brace tapping the top. Closer to the bridge it's about a whole step lower (went too far?), and it's hard to discern by the neck block. By the bridge the height is a bit over 1/2" and it's 3/16" at the lower block, a bit taller than 1/4" at the neck block. I left the height a bit higher by the pickups for structural purposes. Being this is a plywood guitar I don't know if the bracing height will affect the performance of the guitar nearly as much as it would with a carved guitar. But with a nice chalk fitted quartersawn brace compared to crappy kerfed brace, why not?
    Attached Images Attached Images Unfortunate top brace fitting in new Gibson ES-275-img_0669-jpg Unfortunate top brace fitting in new Gibson ES-275-img_0668-jpg Unfortunate top brace fitting in new Gibson ES-275-img_0670-jpg Unfortunate top brace fitting in new Gibson ES-275-img_0673-jpg Unfortunate top brace fitting in new Gibson ES-275-img_0674-jpg 
    Last edited by vejesse; 08-10-2019 at 05:21 PM.

  15. #14

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    Wow! I love the pics.

  16. #15

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    Nice job fitting the new braces. I particularly like the tapering below the bridge region. This will lower the frequency in that area and impart a nice bass response.

  17. #16

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    Goid job! Probably will turn out to be a mighty fine guitar - can’t go wrong with P90s in a (thinline) hollowbody!

  18. #17

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    Quote Originally Posted by vejesse
    Any archtop builders care to critique the bracing scheme?
    Since I'm building from scratch, I don't often stop and tap a top after it's on the rim. Not that it's right or wrong, but I make those decisions before the plate is attached to the rim. From an experienced gut feeling, I like what you've done. When compared to the the Gibson braces, your's are tapered more. Because your braces are not kerfed and fit properly, the final stiffness may be similar to the stock braces but your's will be lighter and that's good. I guess your brace blanks are similar to the Gibson, possibly .3" wide and .5" tall and that's a reasonable starting size because it's a smaller body. I don't think you've gone too far. You've left lots of stiffness between the bridge and the neck block, similar to the Gibson, but possibly loosend up the between the bridge and the tail block and that seems reasonable unless your trying to make it work as a Rock guitar.

  19. #18

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    Thanks for taking the time to give me some feedback Barry. The braces are 0.425 wide" and they are vertical grain Engelmann spruce. That spruce is pretty soft, maybe sikta would have been better but I ended up with a bunch of 7/16" Engelmann spruce guitar bracing stock. I don't have much experience building guitars but I have installed many upright bass - bass bars, and they seem to perform a similar function. With those as a starting point at least I like to tap the bar, then tap the top right alongside the bar, thinning the bar until notes are the same. If the bass bar looks too big I'll go further then, maybe ending up one whole step lower. I'm not sure if the tapping thing has any real magic, but at least you're not working blind.

    I remember that the Gibson 275 I had earlier seemed like it didn't have a lot of bass response, but the highs didn't seem that great either. I wanted at least try to improve the lows a bit by thinning the lower end of the braces.
    Last edited by vejesse; 08-12-2019 at 03:10 PM.

  20. #19

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    Quote Originally Posted by vejesse
    Any archtop builders care to critique the bracing scheme? Towards the lower end I was able to get a brace tap tone very close to the same note as compared to right next to the brace tapping the top. Closer to the bridge it's about a whole step lower (went too far?), and it's hard to discern by the neck block. By the bridge the height is a bit over 1/2" and it's 3/16" at the lower block, a bit taller than 1/4" at the neck block. I left the height a bit higher by the pickups for structural purposes. Being this is a plywood guitar I don't know if the bracing height will affect the performance of the guitar nearly as much as it would with a carved guitar. But with a nice chalk fitted quartersawn brace compared to crappy kerfed brace, why not?

    Keep on replacing crappily glued kerfed braces by nice chalk fitted and tapered braces!

    Just one thought: Gibson and other manufacturers (like Roger in old Germany) used resp. still use quite simple rectangular bars (cross-section). This is desirable from the cost-cutting POV. It's also ok from the functional POV (stability) on mainly electric laminated thin hollowbody archtop guitars. It may even be ok for some carved full-hollow-bodies - but it's not the end of the road!

    Your slight tapering of the braces is a good start for going further. Just have a look on the shape of the bass bar of some fine master cellos; the old masters found the shape empirically during centuries. Much later their work was approved by Jakob Steiner's theorem. Steiner's area moment of inertia calculations are still the foundation of determining the cross-sections of beams in architecture and engineering - valid also for our archtop tonebars! For many archtop guitar makers this seems still to be an alien concept; hopefully this will change in the future!

    Excellent guitar makers (like the one my last avatar - now deleted for possible German patent law requirements - stood for) use(d) the old masters' and Steiner's insights for their work. So, for really fine tonebars (stiffness/weight relation) we'd expect a much stronger tapering, a height of at least 1", combined with a slimmer width … Steiner said it all.


    No commenting here on "brace tap tones", and other stuff that I consider to be widely esoteric, though now (by means of my guitar restoring and production engineer friend who has gathered about 15,000 features and exact measure points on the guitars my avator was pointing to) the procedure could be told how a master maker handled the fitting and selection of tonebars to the tops, and other approaches like the so neglected neck modes. Unfortunately, due to recent and hardly predictable developments with this maker's work in Germany, I doubt the public will get to know exact results in the near future.
    Last edited by Ol' Fret; 08-12-2019 at 09:45 AM.

  21. #20

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    That's rather wide, not that it's wrong, but I am a little more in the tall/thin camp. I don't know that I would thin them further with out being there to feel/hear what the top is doing, but you might taper the top to what in the link below is called "parabolic shape". This removes a lot of mass from the brace while changing the stiffness very little.

    http://ultimate-guitar-building.com/...ceprofiles.jpg

  22. #21

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    Yes, a tall and thin parabolic tonebar profile would be ideal!
    Ok, let's not be more papal than the pope, time is money! Something like approximate parabolic profiles can be prefabricated and would be desirable in any serial production.

    Unfortunate top brace fitting in new Gibson ES-275-guitar-brace-profiles-approximately-parabolic-jpg

  23. #22

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    Time to move on.
    Attached Images Attached Images Unfortunate top brace fitting in new Gibson ES-275-img_06811-jpg Unfortunate top brace fitting in new Gibson ES-275-img_06821-jpg 

  24. #23

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    It went from being an authentic piece of junk to looking like it’s going to be a sweet player. At least it didn’t end up under the dozer treads.

    This is is the reason why I hate buying acoustic guitars sight unseen. My Godin is the only time I’ve done it because I knew I had 14 days, no questions asked.

  25. #24

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    Gibson needs to take some lessons from Eastman and work up to Eastman standards.

  26. #25

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    As a novice fellow bracer, I appreciate the cool thread! Fine work.

  27. #26

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    Special thanks to Dan Shinn and company of Lays Guitar in Akron Ohio for re installing the back binding and touching up the lacquer.
    Attached Images Attached Images Unfortunate top brace fitting in new Gibson ES-275-img_0801-jpg Unfortunate top brace fitting in new Gibson ES-275-img_0802-jpg 

  28. #27

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    Quote Originally Posted by Ol' Fret
    Yes, a tall and thin parabolic tonebar profile would be ideal!
    Ok, let's not be more papal than the pope, time is money! Something like approximate parabolic profiles can be prefabricated and would be desirable in any serial production.

    Unfortunate top brace fitting in new Gibson ES-275-guitar-brace-profiles-approximately-parabolic-jpg
    If the only purpose of the brace is to provide maximum supporting stiffness with minimum weight, removing material from the outer edge by tapering produces exactly the opposite effect. The ideal brace would surely have an 'I' cross section like a girder.
    In fact, if you consider a kerfed brace, having many quite wide kerfs and being glued in place with care so that it looks like a spaced series of small blocks joined at the top by a solid strip that would be loaded in compression, would you not have an ideal low mass stiffener?

    Arthur

  29. #28

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    This is actually a brace design that has been experimented with in the violin world. You fit a bass bar that has interrupted sections or "cut outs". It hasn't really caught on for some reason, but it is commonly used to allow you to fit crack repair cleats under the bass bar when the crack runs right along the bar.
    Attached Images Attached Images Unfortunate top brace fitting in new Gibson ES-275-bar-jpg 

  30. #29

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    That really is shamefully sloppy; how can Gibson fall so low and not die of shame? That's only the 2nd example I've seen so far - the other was a new SG with the finish peeling off the headstock and outright broken off the neck, as if someone had quickly frozen and thawed it, then dipped the headstock in nailpolish remover - but in both cases it's grotesque "don't care, will sell" rather than a little negligence. Very disappointing.

    p.s. I like your double bass site

  31. #30

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    << If the only purpose of the brace is to provide maximum supporting stiffness with minimum weight, removing material from the outer edge by tapering produces exactly the opposite effect. <<


    Providing stiffness is the main function of tone bars. Tapering the ends of the bars towards the plate - where the string load is insignificant - is essential from the engineering point of view in order to get a maximum smooth transition without abrupt weak spots or places of mechanical (and vibrational) discontinuity. Ideally, the bars would taper out flat to the plate surface.

    The making of fine acoustic archtop guitars is all 1. about mechanical stiffness, and 2. smooth propagation of waves. This is the same as are tap tuning methods used by some luthiers. Stiffness translates into tap tone, and vice versa. Some feel it, some others hear it, again some others use both approaches, the majority uses empirical standards (that can vary a lot depending on the wood, the construction, the intended sound ideal, the continent, the actual musical fads, etc.). And the industry workers have to follow fixed values. Period.

    It would probably make not much difference if you'd use elaborated shaped tonebars or simple rectangular braces in a guitar construction like the ES-275, so Ockham's Razor would be appropriate.

    Also, there's a reason why archtop luthiers don't elongate the tone bars by glueing them into the blocks or the lining (which should provide even more stiffness): the body construction has to be as stiff as possible, at the same time allowing the plates to resonate freely and undisturbed. That's why most acoustic archtops feature the arched construction, bracing only where it is necessary, and two lateral f-holes.

    Girder in architecture or technical construction, etc., follow the same physical principals as our archtop guitar's bracing, but buildings or airplanes are built to prevent and avoid vibrations and resonances. The construction of a new main spar for an aerobatic plane is demanding. Two goals are the same as with our tonebars: to provide maximal stiffness at lowest weight. But, again, (uncontrolled) vibrations and resonances are the enemy of strictly static constructions. Airplane constructions with simple rectangular dimensioned and crafted wooden spars were not longer used after the 1930s. Watching the tone bars of many a new archtop guitar reminds us that we're still living in the archtop guitar Stone Age. As an excuse we have to consider that after the 1950s the further development of the acoustic archtop guitar halted, except visual embellishments.

    The theory of bracing was developed in the 19th century. It is called 'parallel axis theorem' or 'Huygens-Steiner theorem' - and no, this is not useless knowledge, but the daily bread of many engineers worldwide, except most luthiers.
    If luthiers would understand or follow Steiner, they'd immediately dump down any thoughts about 'kerfed' tone bars. Or about routing (integrate) bars out of the soundboard wood. Such constructions follow solely cost-cutting or marketing standards, result in overbuilding (or failure) and worse stiffness-weight relations.
    Newer developments, like the use of composites, etc., would make sense. However, luthiers are woodworkers, sticking to wood as their main material. Ok, wood is sustainable and ecofriendly. So, please, for acoustic archtop guitars, give the wood the best possible shape!






  32. #31

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    This approach works quite well:
    Attached Images Attached Images Unfortunate top brace fitting in new Gibson ES-275-hof-new-president-bracing-jpg 

  33. #32

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    Funny, I now own 3 hollowbodies without bracing. Two of those have the typical Asian low budget construction of a sound post under the bridge instead of tone bars to prevent the top from sinking (the third - as you all might know by now - is my ES-125 that came to me with the tonebars missing so the sound post was a necessity). I find that this way of constructing hollowbodies yields nearly identical sound results as the construction with tone bars.... (These guitars all have laminated tops, so I don’t know if the same goes for solid or even carved tops - but I don’t think so). In my Japanese ES-175 copy I experimented with glueing in tone bars (between neck and bridge, since longer tonebars wouldn’t fit thru the pickup cavities). Big no-no! The tone became very brittle and treble-ish.... removed them and the nice woody thunk this guitar had was back (I had a suspicion so thankfully I used water solvable wood glue). So apparently restricting top movement too much and making it too stiff emphasises the trebles and results in a very thin tone.

    My ES-125 with its sound post and missing tone bars sounds better than all other ES-125s I have compared it too (lots of jamsessions with different other 125s): dry, woody, thunky, very good definition, clarity without being sharp. But I am probably biased..... ;-)
    Last edited by Little Jay; 10-24-2020 at 04:01 AM.

  34. #33

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    Since a few years I have this feeling, if I can restart my life I would be luthier...which is way far my daily job, so please bear with me. Can anybody explain would be the impact of those manufacturing errors? Is it soundwise, or mechanical stability... I have no clue...

  35. #34

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    Quote Originally Posted by Gabor
    Since a few years I have this feeling, if I can restart my life I would be luthier...which is way far my daily job, so please bear with me. Can anybody explain would be the impact of those manufacturing errors? Is it soundwise, or mechanical stability... I have no clue...
    Here are my amateur comments.

    1. The sloppy work on that ES-275 is an embarrassment to Gibson. The guitar design was not executed, and it should have never left Memphis.

    2. The majority of the customers wouldn't have done a mirror exam and caught it.

    3. Most players and listeners couldn't tell the difference, especially amplified, even if there was a difference.

    4. The longevity of that instrument likely was not affected by its bracing.

    So is it no harm, no foul? No, not in my opinion. It's like when Gibson started making the "swiss cheese" LPs without telling the public. We are entitled to know what's under the hood, that's all.

  36. #35

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    Quote Originally Posted by BBGuitar
    Gibson needs to take some lessons from Eastman and work up to Eastman standards.

    Meh ... I'm sure Eastman has it share of lemons too

  37. #36

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    Quote Originally Posted by Lobomov
    Meh ... I'm sure Eastman has it share of lemons too
    I am sure this is not the case. Eastman has its handicap, I mean MIC, and that brand must prove continously to increase or even keep its market share. As opposite, Gibson is sitting on his throne. Not the same situation.