Thru body bridge and ferrule location

stevensivak

stevensivak

Dec 24, 2014
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Ann Arbor, MI
#1
When locating the ferrule centerline in relationship to the outside edge of a bridge with holes in it, what
is the offset required? I assume that it must be outboard by some distance to avoid weakening the strings
but not too far away such that the angle does not cause excess stress on the body wood as it passes thru
to the ferrule.
 
#3
stevensivak said:
When locating the ferrule centerline in relationship to the outside edge of a bridge with holes in it, what
is the offset required? I assume that it must be outboard by some distance to avoid weakening the strings
but not too far away such that the angle does not cause excess stress on the body wood as it passes thru
to the ferrule.
Click to expand...

I don't know if there's any real limiting distance range in either direction. Up close against the back of the bridge isn't going to overstress the string, as long as the saddle has some radius to it. That is, the back edge of the saddle isn't a sharp edge.

At the other end, where the string turns down into the body, there should also be some kind of ferrule or metal reinforcement on the top side. As long as it provides some radius for the string to bend over, the bend won't hurt the string. And don't allow the string to bend over the edge of a bare hole in the wood. That won't hurt the string, but it will crush the wood.

So it isn't about distance or break angles. The important things are: Don't bend the string over a metal sharp edge, because that might kink and damage the string. And don't bend the string over a wood edge, because that might crush the wood.
 
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#4
Having used string thru bridges for nearly 40 years I've never had any string, intonation, or breakage issues of any kind. While it's always good to anticipate potential problems before starting a project you should be fine just centering the ferrule. Even after moving used strings from bass to bass I've never had any problems.
KAgwdAsRTcu0mYWNDvXEMQ_thumb_11684.jpg


The bigger issue is making sure the bit doesn't drift as you drill thru the body. Good luck, OP! And keep us updated on your progress.
 
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#5
I’ve always drilled straight through from the bridge through hole locations. There’s a couple of tricks with a drill press that can help make sure the holes are nice and lined up on both sides of the body. As 2saddleslab mentioned bits can wander if you just try to hog through from one side and having the ferrule holes not in a neat line on the back is disappointing.
 
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#6
Bruce-
Thanks for your reply! I think a needle file will allow me to soften the outside edge of the holes in the bridge.
Makes sense about the entry hole- I can't say I have ever seen a metallic insert on the top of a thru string
body. I have searched Google but can't find any images....
The photo above does show me that the break angle (on this bridge) is around 45 degrees.

Very interesting saddle- any idea who made it?

Here is what I can find in nickel:
 

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#8
Matt Liebenau said:
I’ve always drilled straight through from the bridge through hole locations. There’s a couple of tricks with a drill press that can help make sure the holes are nice and lined up on both sides of the body. As 2saddleslab mentioned bits can wander if you just try to hog through from one side and having the ferrule holes not in a neat line on the back is disappointing.
Click to expand...
Agreed!
IMG_2469 2 copy.jpg


Not sure if it helps but here is a thread showing my string thru install.
 
#12
That saddle is of a different configuration than the one posted above- your string hole can ONLY be under the holes in the saddle.
The saddles that are available have the strings leaving the rear upturned edge and thus must be located outboard of the end of the saddle.
 
#13
stevensivak said:
That saddle is of a different configuration than the one posted above- your string hole can ONLY be under the holes in the saddle.
The saddles that are available have the strings leaving the rear upturned edge and thus must be located outboard of the end of the saddle.
Click to expand...
Not exactly sure what you're saying, sorry. But the bridge you show in the pic is not a string thru design. It has 5 screw holes to attach the bridge and the strings are top loading that go thru the bridge, not the body.
 
#15
stevensivak said:
What does "straight through from the bridge through hole locations" mean? A pic would be helpful!
Click to expand...


I was referring to the type of bridge 2saddleslab posted above. If you mean the Gotoh bridge in post 6 I suppose you could run the strings through the bridge and into the body but it’s intended to have the string ball ends seat on the plate just below the intonation screws.

If you want to see the metal collars Bruce was talking about look up how the old Gibson 2 point bridges mounted.
 
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