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saddle slot location
http://luthiersforum.com/forum/viewtopic.php?f=10137&t=52128
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Author:  Conor_Searl [ Tue Jul 02, 2019 5:11 pm ]
Post subject:  saddle slot location

So am I missing something?

This guitar had been converted to a lefty at some point, and the new owner wants me to put it back to right handed. I've filled the slot and got myself ready to cut a new slot. But measuring the scale length at the 12th fret, makes it look like the scale length should fall at 24 5/8". that puts the scale length pretty much at the front edge of the bridge. I had expected to add 5/64" to the high e slot for compensation, and 15/64" to the low e. But that ends up putting the high e pretty close to the front edge of the bridge, is it likely this bridge is in the wrong place? Or is the treble side of the bridge being that close to the edge normal?

Its a 1957 Gibson LG-1.

Author:  Bryan Bear [ Wed Jul 03, 2019 8:39 am ]
Post subject:  Re: saddle slot location

Is that slot in the second picture the one you cut for the new righty saddle? I can't tell what is going on exactly. Is the old (lefty) slot plugged or are you just holding wood there for the picture?

Was the bridge replaced when it was converted to lefty or can you see where the original slot was?

Author:  Freeman [ Wed Jul 03, 2019 10:10 am ]
Post subject:  Re: saddle slot location

I have had very good luck putting the center of an acoustic saddle at the scale length (double the distance from the nut face to the crown of the 12th fret) plus 1/16 on the high E and 2 or 3/16 on the low E. That allows for me to push the break points to the front of the saddle for the high E and G, to the back for the B and low E. Close enough for my old ears.

If you really want to do it right

https://www.liutaiomottola.com/formulae ... sation.htm

Author:  Conor_Searl [ Wed Jul 03, 2019 11:29 am ]
Post subject:  Re: saddle slot location

Bryan Bear wrote:
Is that slot in the second picture the one you cut for the new righty saddle? I can't tell what is going on exactly. Is the old (lefty) slot plugged or are you just holding wood there for the picture?

Was the bridge replaced when it was converted to lefty or can you see where the original slot was?


Haha, Bryan have you ever watched the TV show "The Office"? There's a scene where it's revealed the inept boss Michael Scott was forced into having a vasectomy by his domineering girlfriend who then made him have it reversed, and done again. This guitar looks like it kind of had a similar experience. From what I can tell the bridge is original. The rosewood plug that's in there is what I just filled the lefty slot with, the light wood going the other way is the original right handed slot, but there's also a sliver of light wood running parallel to the slot I just filled, which makes me think it was either originally left-handed, the left-handed slot was in the wrong place and then moved slightly, or the lefty slot was shimmed with the same material that the righty slot was filled with to make a tighter fit for the saddle. I'm not sure.

Author:  Bryan Bear [ Wed Jul 03, 2019 11:42 am ]
Post subject:  Re: saddle slot location

I remember that episode! :)

I see, now. The light colored wood is the original slot that pretty much lines up with where you would put it. It does seem pretty close to the edge. I wonder how long it was in service in that configuration.

Author:  Quine [ Wed Jul 03, 2019 12:00 pm ]
Post subject:  Re: saddle slot location

Maybe its the photo...but I'm seeing more like 24 13/16 to 24 27/32 scale. That would give you some more room on the bridge

Author:  Freeman [ Wed Jul 03, 2019 4:41 pm ]
Post subject:  Re: saddle slot location

I agree with Quine. I see the 12th fret at 12-6/16 plus. That means the scale is 24-13/16. When I put a business card up against your ruler and the center of the slot in the bridge I see 24-12/16 at the high E. In my opinion the slot is too close to the front edge of the bridge - I would have put the center of the high E slot at 24-14/16.

I also think the slot is too close to the front of the bridge from a structural standpoint.

I'll add two more comments - I don't understand the light wood in either slot - it looks to me like the slots go thru to the top. They shouldn't. Also the pin holes look wonky - almost like they were reamed at an angle. All of this could be just camera angle, my bad eyes or things that I don't understand about what you are doing.

Author:  Conor_Searl [ Wed Jul 03, 2019 4:44 pm ]
Post subject:  Re: saddle slot location

Quine wrote:
Maybe its the photo...but I'm seeing more like 24 13/16 to 24 27/32 scale. That would give you some more room on the bridge


Hold on, should a person measure to the center of the crown on the 12th fret or to the edge of the fret on the bridge side?

When I look at that picture I posted and at my ruler, it seems like the center of the 12th fret falls at just under 12 5/16". Am I missing something?

Author:  Freeman [ Wed Jul 03, 2019 4:50 pm ]
Post subject:  Re: saddle slot location

Conor_Searl wrote:
Quine wrote:
Maybe its the photo...but I'm seeing more like 24 13/16 to 24 27/32 scale. That would give you some more room on the bridge


Should a person measure to the center of the crown on the 12th fret?


In theory you should measure the vibrating length of the string. That normally is from the crown.

One other comment - I looked at a couple of other pictures of LG-1's on reverb - their slots aren't as close to the front of the bridge as yours.

Author:  Bryan Bear [ Wed Jul 03, 2019 5:33 pm ]
Post subject:  Re: saddle slot location

I assumed that was camera effect (and still think so)and went by the measurements provided.

Author:  DanKirkland [ Wed Jul 03, 2019 7:03 pm ]
Post subject:  Re: saddle slot location

Conor, before you slot anything take a 1/8" rod (flexible metal) and lay it on the bridge, string it like normal and set it like you would for a saddle. You can see if it will actually intonate correctly like this and you've not had to actually cut anything. If you can't get it to intonate accurately at all with this then there's some other problem afoot.

Image

Author:  Conor_Searl [ Wed Jul 03, 2019 7:16 pm ]
Post subject:  Re: saddle slot location

DanKirkland wrote:
Conor, before you slot anything take a 1/8" rod (flexible metal) and lay it on the bridge, string it like normal and set it like you would for a saddle. You can see if it will actually intonate correctly like this and you've not had to actually cut anything. If you can't get it to intonate accurately at all with this then there's some other problem afoot.


I like this. I'll give it a go!

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