proper way to shave-down saddle to lower action

[Arthur Sweeney]

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.

 

[Ron Frazier]

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 .

 

Ron

[Paul Hostetter]

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.

[Mark Pollock]

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.)

[Murray MacLeod]

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.

[Tom Mitchell]

Post a picture of your set-up!!!

[Mike Kolb]

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.

 

[Paul Hostetter]

And bungled in many others. 

 

I love "rocket surgery!"

[Mark McLean]

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. 

Mark

[Tim Mace]

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!!

[nathan clark]

Another vote for bottom-sanding on drop-in saddles.

Here's my routine:

http://fingerlakesguitarrepair.com/pages/diy/play-ability-for-the-p...

[Paul Hostetter]

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. 

[nathan clark]

Oooops, here's the updated URL:

http://fingerlakesguitarrepair.com/play-ability-for-the-proletariat/