Sable bridge material?

L3stat · #1 09-03-2021, 02:20 AM

Hi all, I've just tried my 1st attempt at setting up my Sable. I've done that for electrics before and know the basics, but have always shied away from doing it for acoustics due to the need to remove material, file stuff etc. On electrics it's mostly turning screws and nuts, easy peasy.

I took down the nut slots, because they were way too high, using a blend of Music Nomad's feeler gauge (0.020 for E, A, 0.018 for D, G and 0.016 for B, E measured at 1st fret) and Frank Ford's measuring as a guide. Had to take a lot of material off! From the factory, a good half of each string was sitting above the nut.

I've just done the saddle, and might have overshot. Was shooting for 0.080 and 0.070 for low and high E, ended up at 0.070 and 0.060. I play more fingerstyle, and no buzzing so far. If it buzzes I'll try a set of mediums (currently have lights).

Now the drastic saddle lowering has messed up the break angles. Does anyone know what the bridge is made of? Some form of CF or plastic polymer? I know the risks of cutting into CF, but in this case the bridge doesn't look like it's made of CF. Does anyone know?

mountainmaster · #2 09-03-2021, 05:52 AM

From the McPherson website: "The body, neck, bridge, fretboard, and bracing is made fully of carbon fiber, with a proprietary blend used on the back and sides."

Does the different break angle affect your tone in any way? Personally I would not mess with it unless it is making unwanted noises.

I lowered the bridge on my Rainsong almost as much as you did and it is still my best sounding CF guitar.

L3stat · #3 09-03-2021, 06:13 AM

Thanks mountainmaster, that’s a great reminder for me to check in with the factory. You have a point, and I can’t tell any tonal difference, but it does bother me. Your break angles actually look fine, definitely better than mine.

I am planning to use my nut files, which cut well and slowly, and take my time. With eye protection and an N95 mask (hope this is fine). I’m guessing unless I use a power tool like a dremel, the chances of fine carbon fibers flying all over should be quite low. And hopefully the carbon doesn’t fray as well. The factory also partially slotted the bridge pin holes, so I suspect I should be ok…

steelvibe · #4 09-03-2021, 07:16 AM

I have a guitar that has the most drastic break angle of any guitar I've ever owned and it remains the quietest.

On the flip-side, like mountainmaster have previously owned a RainSong that had the most drastically low break angle and it had plenty of projection.

I'm not claiming to know more but this is based on personal experience. We have to keep in mind that CF is different than wood and how they respond to string tension. McPherson braces their tops but it isn't for strength, it is for tone shaping. If I had to guess I would say your guitar is just fine. While it couldn't hurt to reach out to McPherson and hear what they have to say there are also folks here on the forum that I really respect the opinion of. One of those folks is Adam Carruth. Here is a pretty good thread with Adam's input in post #44:

https://www.acousticguitarforum.com/...=482555&page=3

Tøf · #5 09-03-2021, 10:31 AM

Quote:

Originally Posted by L3stat

From the factory, a good half of each string was sitting above the nut.

It’s actually by design. I hope you didn’t cut too deep! But I see you’re playing with a really low action.

L3stat · #6 09-03-2021, 10:39 AM

Thanks for sharing, interesting thread! I don't doubt the physics mentioned there, but one artifact about my guitar that worries me is the angle the string makes after it leaves the bridge pin hole, it's almost 90deg. I wonder if such an extreme kink weakens the strings, especially when will be stretched while tuning up. Clearly the strings are still functional in my case, but a gentler angle (and hence better break angle) would reduce such extreme kinks. The only other kink in the string is at the tuner posts, but then again the string doesn't get stretched over that kink. I'll hear what McPherson has to say. Chances are if it won't hurt the guitar (or me), I'll probably go ahead for peace of mind.

Quote:

Originally Posted by steelvibe

I have a guitar that has the most drastic break angle of any guitar I've ever owned and it remains the quietest.

On the flip-side, like mountainmaster have previously owned a RainSong that had the most drastically low break angle and it had plenty of projection.

I'm not claiming to know more but this is based on personal experience. We have to keep in mind that CF is different than wood and how they respond to string tension. McPherson braces their tops but it isn't for strength, it is for tone shaping. If I had to guess I would say your guitar is just fine. While it couldn't hurt to reach out to McPherson and hear what they have to say there are also folks here on the forum that I really respect the opinion of. One of those folks is Adam Carruth. Here is a pretty good thread with Adam's input in post #44:

https://www.acousticguitarforum.com/...=482555&page=3

L3stat · #7 09-03-2021, 10:42 AM

Quote:

Originally Posted by Tøf

It’s actually by design. I hope you didn’t cut too deep! But I see you’re playing with a really low action.

No buzzing when playing open strings hard, so I think I'm ok. There's still good room over 1st fret, and doing the Frank Ford measurement.

Can you share why McPherson does it that way? What are the design considerations? The nut slots were quite high from factory, and they did make the lower frets harder to play.

Tøf · #8 09-03-2021, 01:49 PM

I have no idea why McPherson is doing it this way with the wound strings not completely recessed. All I know is that the nut is supposed to be compensated (and patented).

As for the depth of the slots, I don't know the Frank Ford's method but when fretting the 3rd fret I only have a very small gap between the strings and the top of the 1st fret. I could probably deepen the nut slots by a tiny tiny bit but nothing that would change the playability for my own playing. But I like my action to be significantly higher than your setup (I play with Medium-Light gauge and a saddle that I shimmed to be a hair higher than the low one coming with the guitar).

It seems the bridge is made of the same material as the saddle, with the same "grainy" finish. It might be Tusq if we believe the description in the FAQ. On the other hand when you buy an extra saddle it is just described as a carbon saddle. Haha it seems I won't be very helpful

L3stat · #9 09-06-2021, 07:05 AM

Quote:

Originally Posted by Tøf

I have no idea why McPherson is doing it this way with the wound strings not completely recessed. All I know is that the nut is supposed to be compensated (and patented).

As for the depth of the slots, I don't know the Frank Ford's method but when fretting the 3rd fret I only have a very small gap between the strings and the top of the 1st fret. I could probably deepen the nut slots by a tiny tiny bit but nothing that would change the playability for my own playing. But I like my action to be significantly higher than your setup (I play with Medium-Light gauge and a saddle that I shimmed to be a hair higher than the low one coming with the guitar).

It seems the bridge is made of the same material as the saddle, with the same "grainy" finish. It might be Tusq if we believe the description in the FAQ. On the other hand when you buy an extra saddle it is just described as a carbon saddle. Haha it seems I won't be very helpful

Ok got it. There's a gradient on the vertical side of the nut facing the saddle. I guess in lowering the nut slot I lost a tiny bit of the compensation.

The Frank Ford way is as you described, fret between 2nd and 3rd, check action at 1st. I know it's really subjective, but I had a large gap on mine. Maybe mine just wasn't that well set up when it left the factory.

I have a feeling you're right about the bridge material, and it's quite clear when you remove the bridge pin, that the bridge itself seems to be a different material from the top. I know sheet carbon, and forged carbon, but never seen carbon that looks just like plastic. I could be wrong though.

L3stat · #10 09-06-2021, 07:17 AM

No news from McPherson, oddly enough. I thought they would at least politely tell me not to ruin my guitar at least. So I've gone ahead and done it anyway.

This was how far I went using the Music Nomad nut slot files, which by the way cut well, but due to the design they weren't that easy to use for this purpose. The blades were square shaped, I had to use short strokes so I don't hit the back end of the bridge pin hole.

End result, I think I could go a bit more on the 1st 3 strings, maybe next time.

And the verdict on tone? No difference at all whatsoever!

But sure does look more pleasing to my eyes.