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Thread: Bridge not perpendicular

  1. #1
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    Default Bridge not perpendicular

    Wondering what tips you guys can share about keeping my bridge perpendicular to the top. The bridge tips very slightly towards the nut--not severly by any means. Whenever I change strings I try and straighten the bridge and it just never seems to end up perpendicular though. I'm not sure the bridge foot is perfectly fitted to the top but I believe it is. And in all honesty surface to surface contact is very good, but I'm concerned over time . It seems that it should be a simple fix.

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    Registered User Roger Moss's Avatar
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    Default Re: Bridge not perpendicular

    When you change strings, do you tune them all up to pitch at once after you have changed all the strings? I used to do it that way and I had that problem all the time. It was from all the strings being pulled forward at once. I started changing one course at a time and tuning both up to pitch before going on to the next course, and I don't have that problem any more.
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    Default Re: Bridge not perpendicular

    I never change strings all at once unless I am doing some other work that I need the strings off (fret work for instance). As Roger says change a course at a time, I change one string at a time. Your bridge may have a good fit to the top, but not a perpendicular fit. I have seen bridges with the foot seating well, but not perfectly straight up, and you may have one of those. It could be refit to the top, a lot of folks like them to lean slightly back instead of perpendicular.
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    Default Re: Bridge not perpendicular

    Make sure the two threaded posts are not bent.

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    Default Re: Bridge not perpendicular

    Quote Originally Posted by AlanN View Post
    Make sure the two threaded posts are not bent.
    That I have not done. If one or both are bent then does that mean a new bridge? My method of string changing is one course at a time sometimes in the order GDAE, sometime EADG, and sometimes GEDA. The mandolin's intonation is just so perfect I don't want to mess with getting it out. Would you have to at least loosen all 8 strings somewhat to try and straighten the bridge?

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    I may be old but I'm ugly billhay4's Avatar
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    Default Re: Bridge not perpendicular

    You would loosen all the strings a bit to straighten the bridge, and straightening it may well affect the intonation as it would move the point where the break over the bridge.
    I'd straighten it anyway and re-adjust for intonation. Not a difficult task.
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    Default Re: Bridge not perpendicular

    You actually can pull the bridge top back to vertical under full tension. Builders and repair people can cause close to heart tremors doing it in front of others, especially when it's their mandolin. We call it, among other terms, "burping". Sit in a chair, put the mando neck between your knees, body flat on top of your thighs, grab the saddle with thumbs on the tailpiece side, index fingers curled around the front (kind of like holding a really thick flat pick), hold your breath, and pull the saddle top back to you. It should slide a little bit back to you. I don't recommend this, but it can be done.

    Regardless of how you move the top of the saddle back, your intonation is going to be a little different. It might even be more perfect.

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    Default Re: Bridge not perpendicular

    My eyes are not that great and it is hard for me to see slightly less than perfect bridge contact. I check by using a thin piece of a magazine page to see if I can slip it under any of the corners of the bridge. If you have full contact and perfect intonation, I'm not sure there is anything to fix.
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    Middle-Aged Old-Timer Tobin's Avatar
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    Default Re: Bridge not perpendicular

    I do what Dale Ludewig suggests. I nearly had a heart attack the first time someone did it to my mandolin, but after trying it a time or two myself, it become no big deal.

    Bridges will start to lean forward over time due to the winding of the G/D strings. Every time you bring a string up to pitch, those windings are grabbing the wood of the saddle and pulling it forward. It may not move at the moment, but it puts pressure on it. Over time, as you change strings (even one-by-one), this cumulative pressure from the strings will slowly start to pull the top of the bridge forward. There just isn't anything that ever pulls the bridge back the other way. Strings always go up to tension being pulled from the peghead. So burping the bridge just becomes necessary. And even if you take all the strings off and completely re-string it, the act of bringing them all up to pitch will just start the pulling process all over again. It's a battle you never win. You just have to keep an eye on it and occasionally burp it back.
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    Default Re: Bridge not perpendicular

    Well I took a couple photos but haven't been able to load them into a message yet. This mandolin was built in 1979 and so as Tobin comments there may be something to the many years of playing and changing strings. Actually the foot contacts completely except for one tiny place on the treble side. This bridge is very light in mass(compared to some bridges I've seen and played) and applies a small footprint on the top. So I feel I would have to be careful "burping". I need to try and get some pics posted here.

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    Default Re: Bridge not perpendicular

    You actually don't have to be "that" careful. Because of the break angle on the back side (tailpiece side) of the strings, it is really difficult to pull it back too far.

  14. #12

    Default Re: Bridge not perpendicular

    I too use Dale’s technique. If the bridge or the saddle has gradually tipped forward from string tension this will often cause it to straighten up. I usually feel a very slight pop and then it’s vertical. Use both hands and make sure you have your thumbs and index fingers on each side of the saddle-in the unlikely event that it tips over you don’t want the adjusters to ding the top. (I have never tipped the bridge in all the years I have done this.) Push at the top so you don’t move the bridge base out of position. If it does not want to move don’t force it. It may be that the bridge base is cut at a slight angle and the bridge is as vertical as it is going to get. I also change strings one at a time and keep the saddle pretty low, both of which tend to minimize lean.

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    Registered User Ivan Kelsall's Avatar
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    Default Re: Bridge not perpendicular

    A good point by AlanN. I had to straighten the 2 threaded saddle posts on a high quality Jazz guitar that i once owned. The bridge was fitted perfectly,but the saddle still leaned towards the nut. I removed the bridge,took off the saddle & re-bent the threaded posts. After that it was spot on.

    Mostly,the bridge leaning towards the nut,is caused by the wound strings pulling on the bridge as you tune it up - it happens all the time. However,if the 'lean' isn't too bad,& the mandolin still intonates properly,it's not a problem.

    I re-strung my Weber mandolin 2 days ago,after removing all the strings & bridge in order to give it a clean-up. I always fit the inner A string first to allow me to set the bridge position & keep it in place. I then fit the other strings & make sure that as i'm slowly tuning the wound strings up,i hold the bridge down to the top with my left hand, & tune up slowly with my right hand. My bridge always ends up vertical. However,mostly,i do as most others do,leave the bridge on the mandolin & change the strings one pair at a time. I only remove everything in order to clean the mandolin,polish the frets & oil the fingerboard (wipe on - wipe off) to keep it looking ok,
    Ivan
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    Default Re: Bridge not perpendicular

    When the bridge was fitted to the top maybe the person doing the work wasn`t holding it straight up so the base would tend to be higher on the back (tailpiece) side so it would lean even though the bridge seemed to fit perfectly....It will take a "good" eye to see this...

    Willie

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    Default Re: Bridge not perpendicular

    Another thing I do is sight bridge orientation by holding the mandolin up to eye level, peering at the bridge position; then, I flip the mandolin over and do the same. You'd be surprised how it looks right sunny side up but over easy, not so much.

    And to the burp: at IBMA one year, Gilchrist took my Gilchrist, placed it between his legs and did the burp. I darn near died.

  18. #16
    Registered User John Soper's Avatar
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    Default Re: Bridge not perpendicular

    The Burp is like that Lady McBeth thang: Screw thy courage to the sticking (burping) point!

  19. #17
    Registered User Ivan Kelsall's Avatar
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    Default Re: Bridge not perpendicular

    Hi Alan - I've heard you tell of that incident before. Personally - i wouldn't even have allowed SG himself to do it - just in case !!
    Ivan
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