Acoustic Guitar Construction

One of the issues/questions I get asked and I have noted on various forums, in print too - is "how high should the fretted finger board plane line up above the bridge surface?" Usually "brushing" or 1/32" is the answer. Of course to take this measurement you place a straight edge on the frets and see where it hovers above the bridge -- sometime it will bump into the bridge. Here's a little secret --- manufacturers including Martin have "several" different bridge thicknesses to choose from --- yes instead of jacking around with the neck joint to get the neck to tip a fraction of a degree one way or another they use a different size (thickness) bridge -- now does that not make perfect sense?

Ken: Think this is great for large manufactures,almost a necessity. But I think the small builder should take a different approach. A few years back I built a guitar with an ebony belly bridge that was quite thick(over .400"). I was not to happy with the general tone of the guitar nor the responsiveness. Someone suggested that I remove some bulk from the bridge. I did and that was a light bulb moment for me in regard to how sensitive that area of the top is to changes in weight or stiffness. I removed 1/4 to 1/3 the weight of that bridge and it completely changed that guitar. More responsive and brightened the sound to where it was one of my better guitars. Since then I have reduced the size of my bridges to 1" by 6" and consider them heavy if they are over 30 grams. Also have established .500" as my top to string distance at the bridge and tinker with the neck set to get it that way with the correct action.I think this has improved my guitars. I know folks like to put some of their own design elements into their bridges,have large bridges that produce excellant guitars and I think that's super. This works for me.
Tom

Tom I address bridge weight in a few other places -- I beleive this question is related more to action and playability and getting the parts on hand to work together. ie a Stew Mac or Martin kits. But yes I agree bridge weight is a major factor to consider -- as a matter of fact bridges supplied in the KMG kits are Rosewood dye Ebony (If I did not tell you would would not realize they were not Ebony wood) I choose to do this becasue I have been convinced that the lighter weight is a Plus tone wise. Research did reveal that todays major Classic guitar makers use Rosewood bridges instead of Ebony for the very same reason.

Tom: I've enjoyed your posts for quite some time, you obviously have a lot of knowledge and I'm glad you are willing to share it. I've benefited a lot.

Would you PLEASE post a few d**n PICTURES of your guitars?????
I'm asking politely for now - but I know people who can be more forceful. More exactly, I know Tony who knows people who can be more forceful, or maybe I know Tony whose uncle Salvio knows people who....in any case, I'm sure we would all like to see some of your work.

Thanks in advance for your courtesy and consideration. I now have Salvio on retainer. :-)

kencierp wrote:now does that not make perfect sense?

If that adjustment is within a certain range i.e. doesn't give you too high or low a bridge. Sometimes I see posts where it's so far off it would not make sense to do that. It may be obvious to some but others would need to know what that acceptable range is.

Not sure what you are saying /asking Tim? If the neck joint especially a dove tail joint, is close to having the straight edge test just brushing the top of the bridge --- what gets done is use a slightly thicker or thinner bridge or lower or taller saddle or both to get the string plane at the desirable range for playablity -- I am suggesting to think in terms of those varibles rather than jacking with the eight surfaces of the joint to try and change the angle +/- .05 dergrees -- this is what is done in the factories including Martin.

I was trying to say that for some they need to know what "close" is and not get confused that just changing the bridge thickness/saddle height will work of they will still have a guitar with an improper neck angle. That neck angle is a common problem for newbies and their close may not be close enough. But the concept is right on and a good one to know option wise. I used it on my last as the str8 edge was just skimming the top of the bridge.