I have a Martin D-15 Custom acoustic guitar. It has a new bone saddle,
but the action is too high on the guitar. There is plenty of height on the saddle
for me to shave it down, but I have never done this before, and I'd like to ask
what the proper way to do this is, and, is this a job for a non-luthier like myself?
The saddle is the one thing you cant hurt on your guitar. Save the originel and start with a new one. Trace around the original and sand aaway all to make it like the old one than sand the bottom of the amout you want . Go a small amont and try it. When you sand the bottom flat hold it to some thing that you know is flat and hold it up to a light and see if it is flat.
I have a old key making machine that I use to flatten the bottom and it is right the first time.
You only need the bottom perfitcly flat if it has a pick up under it .
I'm guess we are now talking about a new bridge, rather than simply altering the saddle to adjust the action, as in the original post.
When I lay out a new bridge, the first procedure, after establishing the height of the blank, is to rout the saddle slot. On a milling table, that slot has a nice surface, and I can continue the rest from there, such as drilling the bridgepin holes, cutting the outside profile, shaping the ends, etc.
I use good unbleached bone saddle blanks that come with tolerances I can rely on. (Not all the commercially available bone blanks are that good, BTW.) Once you have a good routed slot and a precisely matching saddle blank, the rest takes care of itself. You only need to trim the ends to fit the slot, and eventually adjust the height during the setup.
For a less-skilled person such as myself, I actually just bought a couple of large dog bones at Petco, cut them in pieces on my bandsaw, and then threw the pieces into a can of acetone for a couple months. The acetone got rid of the copious grease, and the blanks were nice and white, but not bleached. I now have tons of blanks, and can make as many mistakes as it takes to get a saddle right, which is really nice - less worries equal better quality work for me.
Not to mention that it's great fun to chat with neighbors while chopping up bones on the bandsaw. (Yes, I have a dedicated cheap-o blade for this.)
I would never take material off the bottom of a saddle. Good saddles are machined to very fine tolerances, and the slot in the bridge also has a carefully machined bottom. The fit of those two surfaces is critical, and it's nearly impossible to take the bottom surface down without compromising it. I see this all the time. You need a vacuum fit to get a good signal. I've seen really supposedly high-end pro shops do that slab of glass thing and never get it right. Often the saddle ends up resting on one edge because of a lack of 90 degrees front-to-back, but more often the bottom surface ends up with a slight arc end to end. Getting all that right by hand is really difficult.
Post a picture of your set-up!!!
Someone, somewhere, at some time made every saddle bottom flat. So, granted, while it's our responsibility to make certain that doesn't get screwed-up, it's not the sacred cow and (as Murray notes) it's not "rocket surgery".
A precision fit can be made. Yes, it takes time and it takes patience, but it's done correctly every day in good shops all 'round the world.
And bungled in many others.
I love "rocket surgery!"
Thinking about Paul's cautionary words I decided that I would try to set up a straight edge to keep the saddle material perpendicular to the flat surface. That is what Ron was getting at also. Your corian strip is a great way to do just that. Consider that idea stolen!
Arthur - don't give up. It is great that you want to take on work on your guitar with your own hands. It is a good way to get to know your instrument and increase your confidence with it. If you mess it up it is entirely fixable. It is not like you are trying a neck reset, or rocket surgery.
This is lovely, but I have three comments:
1) it is so much easier to reprofile the top than to go through all this. Time is money if you're actually doing this for a living.
2) often, after some years, the top bellies, and the saddle gradually goes with it and the bridge. So when you do this procedure, you're putting a flat-bottomed saddle into a curved-bottomed slot it no longer fits.
3) some shops I know who do this still wind up with saddles with curved bottoms. You can hear the lack of contact, you can pull the saddle and see it with a good straight edge.
Oooops, here's the updated URL: