How to reduce the weight of this bridge?

Discussion of all aspects of multi-string guitars, namely those with 7 or more strings.
HNLim
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How to reduce the weight of this bridge?

Postby HNLim » Mon Nov 21, 2016 1:25 pm

I need some advice from our experts. How do I reduce the weight of this bridge. This bridge is meant for my 14-string harp classical guitar. It is currently 42gms and I am targeting to reduce it to 30gms. Any advice will be helpful. Thank you very much!

Lim HN
14-4a.png

14-5a.png
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1978 Yamaha GC30A - S/BRW
2012 Esteve Adalid - S/BRW
2014 Sen #5 - S/BRW
2016 HNLim - S/BRW-
1974 S.Yairi 950 S/BRW - converted to10-string-2015
HN Lim 14-string - S/BRW - Very close to completion.
1974 S.Yairi 800 : Retired

Ricardo Barros
Amateur luthier
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Location: Brasil

Re: How to reduce the weight of this bridge?

Postby Ricardo Barros » Mon Nov 21, 2016 5:47 pm

I had a similar problem with mine. I used EIR instead of BRW to reduce the weight. I kept the dimensions of the bridge the same as usual for a six string (except of course for the longer tie block).

So, you could considerably reduce the dimensions of the wings of the bridge, and that should give you a few grams.
Your tie block looks fat. Probably you could reduce its thickness too. It´s ok to leave a gap of a few mm between the tieblock and the ramp for the saddle.

Here is how my bridge ended up.

13string52.jpg
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Sergio Abreu 2012 (sp/ir)
Ricardo Barros 2013 (cd/ir)

HNLim
Posts: 2089
Joined: Tue Jul 26, 2011 1:02 am
Location: Singapore - The City in a Garden

Re: How to reduce the weight of this bridge?

Postby HNLim » Mon Nov 21, 2016 8:06 pm

Ricardo Barros wrote:I had a similar problem with mine. I used EIR instead of BRW to reduce the weight. I kept the dimensions of the bridge the same as usual for a six string (except of course for the longer tie block).

So, you could considerably reduce the dimensions of the wings of the bridge, and that should give you a few grams.
Your tie block looks fat. Probably you could reduce its thickness too. It´s ok to leave a gap of a few mm between the tieblock and the ramp for the saddle.

Here is how my bridge ended up.

13string52.jpg

What is the height of your bridge?
1978 Yamaha GC30A - S/BRW
2012 Esteve Adalid - S/BRW
2014 Sen #5 - S/BRW
2016 HNLim - S/BRW-
1974 S.Yairi 950 S/BRW - converted to10-string-2015
HN Lim 14-string - S/BRW - Very close to completion.
1974 S.Yairi 800 : Retired

HNLim
Posts: 2089
Joined: Tue Jul 26, 2011 1:02 am
Location: Singapore - The City in a Garden

Re: How to reduce the weight of this bridge?

Postby HNLim » Tue Nov 22, 2016 12:06 pm

IMG-20161122-WA0002.jpg


Is drilling holes on the tieblock a good idea to reduce weight?
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1978 Yamaha GC30A - S/BRW
2012 Esteve Adalid - S/BRW
2014 Sen #5 - S/BRW
2016 HNLim - S/BRW-
1974 S.Yairi 950 S/BRW - converted to10-string-2015
HN Lim 14-string - S/BRW - Very close to completion.
1974 S.Yairi 800 : Retired

Marshall Dixon
Posts: 376
Joined: Fri May 15, 2015 5:06 pm
Location: Almeda mine, Oregon

Re: How to reduce the weight of this bridge?

Postby Marshall Dixon » Tue Nov 22, 2016 4:35 pm

HNLim wrote:IMG-20161122-WA0002.jpg

Is drilling holes on the tieblock a good idea to reduce weight?


I have done that. Whether it's a good idea or not, I don't know. As Mr. Barros suggests, I'll lessen the tieblock mass first and lower the space between the tieblock and the saddle slot if further reduction needed.

What about removing the wings completely?

Ricardo Barros
Amateur luthier
Posts: 60
Joined: Thu Dec 18, 2014 8:04 pm
Location: Brasil

Re: How to reduce the weight of this bridge?

Postby Ricardo Barros » Wed Nov 23, 2016 2:53 pm

What is the height of your bridge?[/quote]

My bridge measures: 18.9 x 3.0 cm. The height varies acording to the guitar, due to small variations in neck geometry and soundboard doming, usualy between 8 and 9 mm. For this particular guitar, the bridge has 8.5 mm in the treble side and 9.0 mm in the bass side.

The tie block has 14,9 cm (spacing between strings of 11 mm) and the lateral wings only 2 cm each.

Regarding the holes in the tie block, I would avoid it or leave as a last measure. I would be concerned regarding structural integrity - 14 guitars strings pulling the tie block are a lot of tension!
Sergio Abreu 2012 (sp/ir)
Ricardo Barros 2013 (cd/ir)

robert e
Posts: 354
Joined: Fri Dec 11, 2015 6:49 pm

Re: How to reduce the weight of this bridge?

Postby robert e » Thu Nov 24, 2016 4:02 pm

Not a luthier, but did study mechanical engineering. Holes or cutouts would reduce the weight of course, and is old hat in many types of construction (like airplanes, actual bridges, etc.). But if that had been my intention, I might have made the bridge thicker than usual to compensate, and I'd have to consider if, and how, the size and arrangement of those holes would affect the rigidity of the bridge overall. I might consider scalloping the wings-- parallel to the strings, but with none of the grooves going all the way back to front, probably starting at the back, each groove going a bit past the centerline, and not too close together. I'm sure I've seen something like that on guitar bridges. Could smooth out to waves rather than grooves, if you really enjoy sanding.

Wow, though! This question made me reconsider the curvy bridges on some antique guitars. I used to think this was a purely ornamental flourish, but of course these curvy shapes are lighter than rectangular slabs would be for a given footprint, without giving up too much rigidity, especially front-to-back. And the way many of them were shaped now look to me like clever ways to taper rigidity toward the ends while losing more weight than a simple taper, and an opportunity to show off at the same time. Am I crazy?

HNLim
Posts: 2089
Joined: Tue Jul 26, 2011 1:02 am
Location: Singapore - The City in a Garden

Re: How to reduce the weight of this bridge?

Postby HNLim » Fri Nov 25, 2016 1:30 pm

C.png

This is the weight that I am getting now. I am thinking of tapering the wings. This will probably yield some more weight saving.
You do not have the required permissions to view the files attached to this post.
1978 Yamaha GC30A - S/BRW
2012 Esteve Adalid - S/BRW
2014 Sen #5 - S/BRW
2016 HNLim - S/BRW-
1974 S.Yairi 950 S/BRW - converted to10-string-2015
HN Lim 14-string - S/BRW - Very close to completion.
1974 S.Yairi 800 : Retired

Ricardo Barros
Amateur luthier
Posts: 60
Joined: Thu Dec 18, 2014 8:04 pm
Location: Brasil

Re: How to reduce the weight of this bridge?

Postby Ricardo Barros » Fri Nov 25, 2016 5:11 pm

Congratulations !

Don't forget that you will have 14 strings pulling that bridge. Don't reduce the glue area too much.

My guitar has a very good volume and treble response, even with a 29g bridge. Yours should be fine the way it is.
Sergio Abreu 2012 (sp/ir)
Ricardo Barros 2013 (cd/ir)


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