Acoustic Guitar Construction

Tim good luck to you. I plan on getting one of those bridge placement things from Ken. Seems the way to go. As all that will be taken care of. Sorry I can't help you.

Tim, that's an interesting machine you show for routing the slot. Exactly what is it?

Yes I agree. Understand why the saddle goes where it goes and then get the bridge setter. It really makes it easy ! er.

John, it is a mill/drill that I bought from a guy at work. It is the cheapest mill/drill that Grizzly makes. It is a bit crude but it only cost me a couple of hundred dollars so I can't complain. It worked great for cutting the saddle slot once I built the little jig to hold the bridge.

Tim,

Beware of David Russell Young's book and what it says about compensation. It has a serious typo on page 132 where he says to add 13 27/32 inches to the 12th fret location to locate the center of the saddle slot. The nominal scale length proposed in his fret table on page 108 is 25.44 inches. So you would be about an inch too long if you used his 13 27/32 inch measurement. What he appears to mean is to include an extra 7/64 inch (.11). If you look carefully at the photo on page 133 you will see that his ruler reads 12 inches plus, not 13 inches plus. Cumpiano advocates adding .15 for the 25.4 inch scaled steel string featured in his book. I use .11 myself as the starting point, then alter the saddle as described below.

Thus, I think your .17 is excessive. 3 degrees off square is a standard angle, though Somogyi suggests 5.5 as better.

With a digital tuner (Peterson makes very good ones, both clip on and stand alone - I use both) you can alter a trial saddle until the harmonic at the 12th fret and the fretted note are as close to the same as possible. You can use a standard ballpark pattern which arranges the lowest four strings along one path from long for the low E to short for the G, then reset it to long for the b and short for the high e. You have a pretty thick saddle that should give you some wiggle room. Sometimes I use a piece of ebony flattened on the top with little pieces of piano wire on top that I roll around to get the best final length, then take a measurement with a micrometer and use them to carve the saddle. If you really want to be fanatic, take the measurements with the instrument strung to pitch with the final brand and gauge of strings you plan to use. The biggest issue, though, is to measure with all the strings tuned to full pitch, rather than just stringing one at a time.

You have to remember that many $100,000 pre war holy grail guitars do not have perfectly compensated bridges. And none of them have compensated nuts. Fully compensated saddles make the largest difference on 12 string gits. Leadbelly, however, did not find them necessary. Recording engineers, on the other hand, tend to love them.

BTW: The mathematical calculations for compensation differences between long and short scaled steel string guitars amount to a couple thousandths of an inch, not really relevant to actual placement of bridges, but technically, the shorter the scale, the less the compensation.

Birth of the KMG Bridge Setter.

I've told this tale many times before -- its 1982, I am rushing to get a commission completed, a Torres Classic. My friend at the Cadillac plant in Detroit is leaving the company moving to California and wants to take the guitar with him. No problem the timing is good all I need to do is string it up and away it goes. However, after I get the strings wound I'm getting these strange fretting results --- duh!!! I had glued the bridge exactly one inch off location -- yikes!

It took that instant to realize why every single critcal placement operation at the Cadillac facillity had a locating fixture -- moral -- no matter your knowledge or skill you will have those "DUH" moments. I recommend at least making a template that has target positions and alignment details.

Good story Ken