String holes in the bridge

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dartemo1

Posts: 76
Joined: Apr. 21 2010

String holes in the bridge

Hello,

I need to repair worn bridge holes in my old guitar. Wondering if new holes can be drilled at a slight angle to the soundboard after filling to increase the break angle and permit using lower saddle? Actually, it also should be easier to drill at an angle.

Thank you and Happy New Year!

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 6 2020 20:32:32

Tom Blackshear

Posts: 2304
Joined: Apr. 15 2008

RE: String holes in the bridge (in reply to dartemo1)

Man O man! You don't make things easy.

Please clarify what type bridge you are describing. Is it a steel strung acoustic or a classical style bridge with nylon strings?

If classical style, then either you'll need special tools or just find a bridge replacement that suits your needs; even something that is close that you can tweak to fit the style.

_____________________________

Tom Blackshear Guitar maker

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 6 2020 22:32:14

Echi

Posts: 1132
Joined: Jan. 11 2013

RE: String holes in the bridge (in reply to dartemo1)

Hi, yes it’s possible.
I did it once, but in my case without drilling to a different angle as I used a jig with a 90 degrees angle for the purpose.

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 6 2020 23:57:03

dartemo1

Posts: 76
Joined: Apr. 21 2010

RE: String holes in the bridge (in reply to Tom Blackshear)

Yes I know that this project is quite involved and chances to screw up are high. Anyway, I have a classical (flamenco bridge), as shown with positions of the old and possible new holes. Thank you.

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REPORT THIS POST AS INAPPROPRIATE | Date Jan. 7 2020 1:39:13

ernandez R

Posts: 739
Joined: Mar. 25 2019
From: Alaska USA

RE: String holes in the bridge (in reply to dartemo1)

Dartemo,

I've been aiming for about 7-8 mm string hight off the top at the saddle and decided to go the twelve hole bridge route to get the necessary break angle.

I also drill my string hole the same angle as the string so it does not cut upward where it enters the tie block. (A)

Another thing I've discovered, I just strung up my #7 & #8, is the 4th string is half the diameter of the hole and it looses a lot of angle accordingly so on my next bridge I will be drilling both the first and fourth string using a much smaller drill bit rather then the .063" I use normally (C)

I have a strong thumb and I can roll the D string on the saddle if there is not enough angle but it could just be my poor technic.

Another option would be to carefully chisel a channel between the aft saddle ramp and forward face of the tie block then drill accordingly. (B)

I have made a thin drill bit extension using thick copper wire, commonly used in the USA as ground wire 4ga. I drilled a hole in the end of a 12" length and then silver soldered the drill bit in place. This way I can drill the holes from the back and get the necessary angle if I am doing a repair.

I'll try to post a couple fotos.

All of this depends on your skill level... it might be better to take your guitar to a pro.

HR

Both of the bridges below are 7.5mm E and 7.0mm e off the top.

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REPORT THIS POST AS INAPPROPRIATE | Date Jan. 7 2020 3:46:29

JasonM

Posts: 2055
Joined: Dec. 8 2005
From: Baltimore

RE: String holes in the bridge (in reply to dartemo1)

I did this a while back. Except I opted to just convert to a 12 hole rather than try and plug the holes and re drill. Dewalt and Bosch sell 1/16 inch x 12 inch long bits. It turned out well except on one of the holes I drilled too far out the other end and into the bridge a little ways. should have protected the bridge in between the saddle slot and the tie block! To help establish the correct angle through the block I drilled a hole through a small piece of scrap wood to act as a guide for the drill bit. But just for starting the holes. Once each hole was partially started I drilled freehand the rest of the way.

Ernendez that sounds like a good idea to slant the holes upward. I guess the disadvantage might be that you loose room on the back side of the tie block for the string knot?

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 7 2020 5:31:44

Echi

Posts: 1132
Joined: Jan. 11 2013

RE: String holes in the bridge (in reply to dartemo1)

Well, you can build a jig to guide your drill with a certain angle.
Without a jig you run too muck the risk the holes will be not in line.
In case you would instead add a set of 6 new holes, in the attempt to convert the bridge to a 12 holes, you should keep in mind that the new holes would be few mm far from the current ones, which means the strings will keep coming out from the actual holes otherwise you would get a different spacing.

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 7 2020 7:40:19

dartemo1

Posts: 76
Joined: Apr. 21 2010

RE: String holes in the bridge (in reply to ernandez R)

Thank you guys for your input. I like the design with the string hole being parallel to the natural string position to prevent cutting the wood. It is quite opposite to my design and definitely calls for a 12-hole bridge to keep the break angle acceptable. I prefer standard bridge and will go ahead, as Jason and Echi suggested, using a hardwood jig for drilling and 12" aircraft drill bits (3/64" for 1, 2, and 4th strings and 1/16" for 3, 5, and 6th strings, and 3/32" to open the holes for redwood dowels, all also available form drillsandcutters). I tested 1/16 on a scrap piece of sapele and it worked fine, although rosewood could be a bit harder. Thanks again.

REPORT THIS POST AS INAPPROPRIATE | Date Jan. 7 2020 19:30:58