Bone Shims - Luthier Tips du Jour Mailbag
In this episode, luthier Robbie O’Brien demonstrates the method of utilizing bone shims to make precise adjustments to saddles and nuts, providing viewers with practical insights into minor setup modifications.
Video Transcription
[on-screen text reads: Luthier Tips du Jour Mailbag]
Mailbag question: Can I use a shim to raise the action on my guitar?
Robert O'Brien: Today's Tips du Jour Mailbag question comes to us from New Jersey. "Robert, I need to raise the action on my guitar, and I don't want to make a new saddle. Can I use a shim under the existing saddle to increase the action? Craig in New Jersey."
Craig, shims are a great way to make minor adjustments to the not only saddles, but also to the nut. Now, I prefer natural bone shims for tonal and aesthetic reasons. In fact, LMI makes shims out of natural bone specifically for this purpose. And they come in at just a skosh under 32nd of an inch, which is perfect for making those minor adjustments.
Figure out how much you need to raise the action
Now let me show you how I do it. So the first thing you need to do is to determine how much you need to raise the action at the 12th fret. Now it's a two to one ratio. For example, if you need to raise it a 64th here, you need to raise it a whole 32nd back here, or exactly twice the amount. And that's about how thick these LMI bone shims are.
Cut the shim down to size and install
So once I've determined how much I need to raise it, then I need to size this. And obviously this is much wider than my saddle slot. So what I'm going to do is take my jeweler's saw and cut this down to size.
[Robert cuts the shim]
If you need to clean up the cut, use a sanding block, this will also help you get it to size if you cut it a little bit too wide. Once you have the bone shim, cut the size, just drop it into the slot and then put the existing saddle right in over the top of it and problem solved. You can do the same thing on the nut end of the guitar.
Other uses for shims
Here's something else you can use the LMI bone shims for. Let's say that you slotted too deep on your nut slot when you were slotting it for the string. Take a piece, glue it into place, cut it off, shape it, and re-slot it.
Yet, another use for the LMI bone shims is let's say that you have a saddle slot that is wider than the bone blank that you're working with. Take one of the LMI bone shims, glue it to the side, and now you have a wider saddle. So, Craig, there's just a few uses for the bone shims available from LMI, and I haven't even mentioned their use in inlay work. It works great for that too. So I hope you found this information useful and happy building.
[on-screen text reads: More Luthier Tips and online courses available at www.obrienguitars.com. Private and small group guitar building and finishing instruction available.]
