Acoustic Guitar Construction

A while back I had to make a pinless style bridge for a guitar to recover from a boo boo. I probably could have recovered in some other ways, but I chose to go with a pinless bridge. This is how I made the bridge.

First I cut the bridge blank to size. I used standard Martin belly bridge dimensions I procured from the Stew Mac web site.


Then I marked the center of the bridge and the locations of the two E strings. I am using 2.25" spacing on this guitar. Once I had those measurements established, I used my string spacing ruler to lay out the locations of the remaining strings. I don't think it would make any difference if I simply made each string equally spaced but I have the ruler, so why not use it?


I then used my drill press to drill the holes for the strings through the back edge of the bridge. Be sure to note the extensive clamping I used to avoid the bridge moving around during drilling. Oh...there are no clamps in this pic? Well I used my right hand during the actual drilling. This pic is staged. I used a 5/64" bit for these holes. I determined this was a good size by guessing. Or by drilling a hole in scrap. I'm not telling.


After drilling the holes, I used a 7/32" bit to countersink the holes. I put tape on the drill bit to keep it from going too deep. I tried to make the countersinks deep enough to almost completely cover the ball ends. I didn't want to go too deep and risk compromising the strength of the back of the bridge.


I wanted to have about .25" of wood from the back of the bridge to the beginning of the slot where the strings start to go up to the bridge. It seemed to me that the saddle would raise the strings up sufficiently that I need not worry about the angle of the ramp in the string slot area. I used the set up in the next pic to slot the bridge and also to cut the slot for the string access.


I wound up with the mess below after cutting the two slots. Once the slot in the back of the bridge was cut, I used a chisel and a dremel with various attachments to cut the ramp.


The curved lines are where I would shape the wings. I used a very precise method for establishing the curves, namely a roll of blue painters tape because the radius was the right size out of all the things laying on my bench at the time.
True story.

I wasn't worried that the slot in the back of the bridge was sloppy. I was going to hack away at it with various sharp and pointy things anyway. After a bunch of sanding, chiseling and a quick wipe with Danish Oil, here is what the bridge looks like:


There you have it. I pretty much made this up as I went along. I had three bridge blanks to work with if I messed up the first, but it all worked out. I had a vision in my head of what I wanted the finished product look like and I figured out as I went along how to get there.
If I missed anything that might need filling in, I will do my best to explain but these are all the pics I took of the process. Well...except for this one:

but it shows less detail than this one:

so I went with #2.
Thanks for looking!

Tony

That's a great photo-essay on the process. Thanks for sharing.

Nice explanation of your technique. Glad you didn't need more than one bridge blank to be successful. What do you think the reduced mass of this bridge does for the sound of this guitar compared to others you have built without the pinless bridge? I know that an extremely subjective answer will follow, but hey, inquiring minds want to know.

Fred

Umm...I dunno. This bridge is 40 grams. It's the only one I have weighed but I think a Martin style bridge is about 34-36 grams so it's probably too fat in some areas. The extra weight hurts attack and helps sustain but I cant even begin to guess what has more of an affect on the overall sound of this guitar.
I'm glad this was at least informative if not helpful to everyone.

When calculating the weight of the "bridge area/assembly" you have to consider the weight of the pins, saddle, bridge plate and the bridge itself. To hear what might be expected of a light weight pin-less bridge guitar that also has very accurate intonation as the result of the "engineered" saddle configurations. Take a listen to a top of the line Ovation (they are not cheap!) and search out a George Lowden. Those old enough may remember Glen Campbell -- he played Ovations. For a long time Glen was the most sought after studio guitar player in the industry -- his credits can be found all over the place including recordings by Frank Sinatra. Point being his acoustic guitar work and sound signature was at the forefront of the music industry.

And the subjective part of the question -- to my ear when the instruments mentioned above are in the hands of an accomplished musician, they indeed do have different qualities as compared to the typical SS sound (AKA Martin) -- more over tones --- more piano and harp like is color.

Re Glen Campbell - a little off-topic, I'll be brief - those who knew him only by his many 'pop' radio hits did not know how he could kick a** on his standard ol' telecaster. I saw him once on a PBS special, when he was older, following a few other younger and flashier players, and he looked out of place - he was dressed well, the string tie, the Southern-style suit, boots, no hat, lean and fit - and I thought: what is he doing there? He started the song - amp set to 'clean', no distortion at all (how could he solo without distortion?) , a pleasant voice and good lyrics, but no show of chops. Until the song was done, when for a few beats in the silence he looked over at the younger guys, gave a little smile, the drummer kicked it off again and he solo'd for a couple of minutes - it made your heart sing - this guy was a master. No cliches in his playing, just state a theme, develop it, add more layers, play fast when it fit, it just went on and on. Plenty of fire. It was obvious he could play whatever he wanted to.