This is my first post. I'm a guitar player, not a luthier. I've done a few setups on my own guitars over the last five years using Erlewine's book and some tools from StewMac; radius gauges, radius blocks, crowning files, and straight edges. I finally had to take my main guitar, an '81 ES-175, to be refretted and it came back buzzing worse than before. This has motivated me to get better at doing my own setups.
I've read all the posts on this forum concerning refretting and setups and there seems to be two main camps on how to approach getting frets level.
1) Use a neck jig to simulate string tension then use long radius blocks or straight files, or
2) Adjust the neck straight with normal string tension and use a 1" straight, sandpaper-coated piece of U-bar.
I have a few questions. If using method #2, how do you get the proper radius to the fret tops? Is eyeballing it good enough?
And why doesn't someone make a hollow metal radius block that you could thread the strings through to get the best of both worlds, i.e. get the correct radius all at once with the true string tension?
The theory of all this is well done everywhere, most of what you are talking about can be done with a ruler and the side of a straight wine bottle (which we have rolling around from time to time) , which visually simulates what happens when you bend a string around a cylinder. Even if the string spread is parallel it still results in bending a straight string around a cylinder or cone. The only practical way to get around this is to have a flat fingerboard.
Low actions are personal choice but still conform to the laws of physics and geometry. particularly when sting bending in the higher fret numbers is required.
We use compounding and drop away to allow heavy bending in the high number frets with-out choking or losing string energy as the strings foul the following frets.
Practically, and by way of my own choice, its a lot quicker to just plug in, bend the strings and work out what compounding is required for a particular player's action height, rather than work out the missile science on a computer and apply it to the frets. But if you have the time and the inclination. it's a free world. The Plek dudes have already done this and you may find something on "the tube" that will enlighten you further.
Anyway, If you need to validate this stuff just build a test bed on your bench top - it takes a few parts and a couple of hours and provides endless hours of fun. You can also test out your programs/simulations against a real world model. It also protects your regular instrument from being Frankensteined.
Good luck on this one Steve, tell us how you went.
You know what I think would be fun to play with is a TOM-type bridge that has adjustable nuts in the vertical direction. You could figure out what the best string heights are for a particular guitar before you start filing away on the real bridge. Anyone seen such a thing?
TOM's do not have nuts. They have saddles. Nomenclature is vitally important to the craft.
There may be ones out there that adjust in the vertical plane, but.... here's where you have to do the research. Do as we all do and spend a couple of hours searching the web for hardware spec's.
All of your interesting, albeit unconventional, 'theories' could take volumes to sort through and respond to. Most of the folks qualified to reply to your questions (and they're limited) are also full time luthiers who also run businesses and their time is extremely valuable. Essentially, each response you receive is like a $50-$100 gift.
I suggest you become familiar with a local tech or luthier and discuss your ideas. He or she can help you sort through the ideas and demonstrate, right on the spot, the outcome. Alternatively, they can demonstrate why your theories may fail, you'll see it right before your eyes and possibly rethink your strategies.
The depth of knowledge needed to interpret and properly respond to "theoretical applications" without having the instrument 'right in front of us' becomes difficult if not impossible at some point. We've given that message to scores of posters. It's simply a fact. I believe we've reached that point with your post, and seeking a 'hands on' tutor will be the very best way for you to explore and execute your goals.
It would be great, after you find a local to guide you, if you could provide us with a write up of what you tried and how it worked out.
Great hunting and best of luck :)
Thanks Paul, That's pretty much it.
What Paul said, you need to do a lot more reading and web research before musing here - time used talking is time not spent doing business and solving extant problems - maybe you can hook up with other theorists on some of the more esoteric forums which cater for advanced thinking. Or maybe a smarter guy than I can help you out here.
The guitar bridges you allude to with adjustable saddle heights are called FENDERS - get one and knock yourself out. Tell us how it went.
"But is the difference noticeable?"
On a Fender with the old 7.25 radius; yes it is if you try to bend notes, epecially on the high register frets (12th and up). The notes will choke out unless you have high enough action. The Gibson 12ish" Radii eliminate that problem and allow lower action for bender guys.You can feel it - if you change it on a re-fret job... which can be good or bad according to your desired feel. I have changed the radius on few guitars and regretted it. Currently, I try to accept my guitars for who they are :) Tom