Official Luthiers Forum!

Hello all, i'm curious to get some opinions on how much wood to leave under the saddle slot and how this could affect tone,any ideas? All the best Rob.

Roby: Mine end up about .150",it is predicated more by saddle blank height(about .400") and string height over the top(about .500") then any other consideration. Not much help but that's my story and I'm sticking to it.
Tom

_________________
A person who has never made a mistake has never made anything!!!

About 3.5-4mm. Bridge is usually 9.5 mm, so a 6-6.5 mm slot depth.

I aim for 3mm

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

If you are worried about tone, what is under the saddle isn't as important as the overall height of the bridge and saddle. A pinned bridge is actually using coupled forces , that means there is an upward pull from the ball end and a downward push from the strings pulling against the bridge causing a rotation force.
About a 1/2 in string height is about the sweet spot. Much more than that can really choke up a top. Once you get below 7/16 you are also not getting enough transfer. Break angle really isn't that important as long as you have more than 5 degrees. But you do want to have about .150 saddle showing.
I like a .350 bridge and .150 saddle to start with.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I try to leave about 1/3 of the bridge thickness. I have replaced a number of bridges and first try to determine if the one I am taking off is the original thickness. Then I figure what string hight I need based on a number of factors but try to base it from the guitar I am repairing. It is usually about 1/2" but can vary slightly from guitar to guitar. What ever thickness of bridge I end up making I try to cut the slot no more than 2/3 of the thickness of the finished bridge and then make the saddle to match that slot depth.

Cheers,
Bob

I usually aim for about 2-3mm.
It really depends on the instrument you are making, height of the bridge. strings and amount of saddle showing above the bridge. Many of my smaller guitars use a 3/8" tall bridge as 7/16-1/2" is basically a Martin spec. It's what you do if you are making a dread-not and using medium or medium light strings.
Larson's used a shallower bridge on their smaller instruments. A 1/2" tall bridge just doesn't fit on a parlor (12-12-1/2" lower bout). That size bridge will choke the top too. There really is no single sweet spot. There are several. It depends on the strings you use too. You don't need a tall string saddle height with light strings on a parlor or concert size.
I always try to get the saddle as deep into the bridge as possible, so on something like a parlor, the saddle sits deeper in the bridge. I just leave enough to maintain the integrity of the bridge.
Of course "open end slot bridges" would be another story...but not mine to tell.

I don't think that at any time a 1/2 in thick bridge should be used. That is pretty excessive Haans I was speaking overall string height , A good rule of thumb is over 1/2 of the saddle in the bridge. You definitely don't want to be too thin. I have seen slots that were about 1/8 under the bridge and seemed ok. I like my slot to be about .180 to .200 deep on a .375 bridge so you would have about .200 to .150 in under the saddle.
On a side note over height at the top in front of the bridge should be 7/16 in to 1/2 in.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Sorry, John, misread that. Too early, no coffee...
Agree, never have used a 1/2" bridge. Think I have used some at 7/16" on GC's and 12 strings, but parlors more like 5/16-3/8" depending on strings.

I figured that Haans
For me it is lack of coffee in the morning and beer at night.
Hitting the neck set is critical .

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Well, don't do the beer part, but sure need the coffee...
Neck set is critical and that is why I finally bought the Luthier tools neck jig. It's very accurate. I like that I can control the neck angle to a very high degree.
I can tell you from mandolin experience that it's amazing what a little change in neck angle/bridge saddle height can do. I spent a lot of time with neck angle changes and also break angles and small changes can make a big difference in the choking of a top or not enough power being transmitted to the top. I've had it both ways. Too shallow an angle and you can't get enough power out of the instrument.
Another thing I just thought of is the fingerboard height. Some times I will use a thicker fingerboard than most because of the way Larsons are built. This usually necessitates a neck angle change.
At any rate, I probably set my saddles deeper than most, but I use a closed end slot.

That is a good point that we didn't address on the fretboard thickness.

Most today are 1/4 in but older instruments used as thin as .180.

While I don't use the neck jig I have one of my own and this can't be stressed enough. If you don't get the neck or right , you are in trouble from the start. I do have a new neck setting video that will be out soon. I think it is one of the best ones I have done. after a few years I think there is something valuable I can pass on.

I will post when it is up.

we are here to help so never be afraid to ask questions.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

John, I looked at your old one several times when I got myself into trouble in the past. It got me through more than one "Oh no..."!