Hi all.

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?

Thank you.


Views: 11148

Reply to This

Replies to This Discussion

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.

With respect, getting a saddle flat, straight and square on the bottom, and doing it by hand,  is as far removed from rocket surgery as it is possible to get.

I cannot speak for "supposedly high-end shops" but speaking for my own shop, I have a granite surface plate to which is attached a strip of PSA 120 grit adhesive. Clamped alongside this strip (in fact overlapping it by means of a tiny rabbet) is a block of 12mm thick Corian, which has a dead straight, dead square edge (machined on the router table) and this edge acts as a fence when sanding saddles.

With this set-up it is virtually impossible to achieve anything other than total straightness , flatness and squareness on the bottom of the saddle.

Far from "never taking material off the bottom", this in fact is the operation which I invariably do as a matter of routine, just to make sure that the bottom of the saddle is in fact straight, and square, before doing any top contouring which may be required.

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!"

Hi Murray

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. 


It's all been done.......bottom, top.That's what action/compensation adj. is..up,down,fwd,bk...precision flatbottom a must for drop ins though..Frank,help us outta here!!
Another vote for bottom-sanding on drop-in saddles.

Here's my routine:

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. 


© 2023   Created by Frank Ford.   Powered by

Badges  |  Report an Issue  |  Terms of Service