Bridge fit

[Br1ck]

I recently strung up my mandolin after finishing it with shellac. I don't know if things changed, or I didn't notice it before, but the neck treble side if the bridge corner is not making contact. I mean no more than 1/16 inch each direction, maybe not that much. It's a full contact CA bridge, and I'll probably wait until next string change to deal with it, but was wondering what if any detrimental effect this would have on tone. We are talking maybe 2% or less of the contact area.

[colorado_al]

2%? Probably no effect at all on tone

[Marty Jacobson]

Fitting a bridge perfectly is impossible (unless you can control temperature and humidity to +/-10 degrees and +/- 10% RH). Ideally the four extreme corners of the bridge are in contact. Mass further away from the centerline has an exponentially larger influence than mass closer in. So the four corners of the bridge are most important to fit. (Look up moment of inertia if you doubt this).
The amount of surface area in contact appears to be largely irrelevant. Do a test with the corners in contact and then "full contact" or as close as you can get. If you can measure a difference, I'll be interested.

[sunburst]

Well, I now have about 30 minutes of internet education on moment of inertia, and I can't see how it relates to a mandolin bridge and what it does when we play a mandolin (let alone how it relates to contact at the ends of the bridge). Marty, can you give me a hint?

[treidm]

I feel for you.....
It's probably how all newbie's feel, when they ask a question and the seasoned veteran posters, use terms and explain things, sometimes in a condescending way...
[Not that he was being condescending, he's just way smarter than me]

It's easy for that to happen, as I've never been thought of as a genius just a regular guy. At least you got SOME education, I didn't get any of it..

[Rob Roy]

How does it sound? My experience has been that CA bridges have a fuller, stronger, more fundamental tone than other makes. If it's full contact, it's hard to imagine one outside "0.060 of the corner would affect tone.

[Br1ck]

The mandolin sounds great. Much better than I could have imagined it would. Very loud and on the bright side. This is more of its bugging me than any why doesn't it sound good issue. Something I can correct rather than all the binding flaws I can't. LOL

[Marty Jacobson]

Well, I now have about 30 minutes of internet education on moment of inertia, and I can't see how it relates to a mandolin bridge and what it does when we play a mandolin (let alone how it relates to contact at the ends of the bridge). Marty, can you give me a hint?

I guess I should have said that my assumption is that what you care about in a mandolin bridge is optimizing rigidity vs. mass.
The mass further away from the neutral axis in a structure imparts far more stiffness per unit of mass than the same amount of mass located closer to the neutral axis.
So if the goal is to get the best connection we can between the top and the bridge, fitting the four corners perfectly is most critical. The further towards the center you get, the less critical the fit is. I'm not saying irrelevant, just less critical.

[treidm]

I guess I should have said that my assumption is that what you care about in a mandolin bridge is optimizing rigidity vs. mass.
The mass further away from the neutral axis in a structure imparts far more stiffness per unit of mass than the same amount of mass located closer to the neutral axis.
So if the goal is to get the best connection we can between the top and the bridge, fitting the four corners perfectly is most critical. The further towards the center you get, the less critical the fit is. I'm not saying irrelevant, just less critical.

[Phil Goodson]

I guess I should have said that my assumption is that what you care about in a mandolin bridge is optimizing rigidity vs. mass.
The mass further away from the neutral axis in a structure imparts far more stiffness per unit of mass than the same amount of mass located closer to the neutral axis.
So if the goal is to get the best connection we can between the top and the bridge, fitting the four corners perfectly is most critical. The further towards the center you get, the less critical the fit is. I'm not saying irrelevant, just less critical.

So, if you just cut off those 4 corners that don't fit well, would you hear a difference?
If so, should we make bridge bases even longer to take advantage of this opportunity?

[Marty Jacobson]

So, if you just cut off those 4 corners that don't fit well, would you hear a difference?
If so, should we make bridge bases even longer to take advantage of this opportunity?

Never mind, I just overcomplicated it as usual.

[Larry Simonson]

Is the fit of the bridge important for other than cosmetic reasons? I suppose poorly fitted bridges are a sign of bad workmanship and blamed for poor tonal performance so I am wondering if someone has investigated this in some sort of objective manner. I am aware of the rather large effects of mass such as violin mutes and hole drilling to increase or reduce bridge mass, respectively, but not of fit to the sound board.

[Stephen Perry]

Two aspects to fit come to mind. First, fitting from bad to nice makes for a more solid sound. Has to be fairly bad for me to immediately look to see what's up. Second, poor fit results in dents in the top.

[Rob Roy]

The mandolin sounds great. Much better than I could have imagined it would. Very loud and on the bright side. This is more of its bugging me than any why doesn't it sound good issue. Something I can correct rather than all the binding flaws I can't. LOL

Yes, of course it's something you can correct. However, you're looking at A LOT of tedious sanding to bring the rest of the bridge foot to the level of the one high corner. Maybe start dreaming about your next build…?