#1
Hello everyone!

I've just got this quite mint 2nd hand Swing guitar (don't worry, my main axe is a Sigma 000mc-4e), and I had a little look inside the guitar as a precaution. Inside, I found wood chip pieces and splinters, which were causing the rattling, a unstuck wire mounting for the piezo, fixed that.

But what really got me worried is that the bridge pin holes, the underside where the ball ends rest and push up against the bridge plate - the sides of the pinholes are splintering. Not sure to what extent or is it bad, and will this cause any tuning instability, or cause the ballend to wiggle out of the hole? I'm sure the latter won't happen, but maybe something else..?
Attached is the image,



And the guitar itself in question, a SM-50TE!

Apologies for the sideways images, my phone uploads them as such, no idea.


Thanks for the help in advance!
Last edited by AORNova at Jun 12, 2017,
#2
It looks to me like they didn't have a block of wood behind the bridge plate when they drilled the holes for the pins so it caused chipping when the bit broke through the plate.  This chipping will make the bridgeplate more susceptible to splitting so you will need to be sure you string it the proper way in order to minimize the chances of that happening.  The best tutorial I have seen on stringing a steel string acoustic can be found on frets.com.  As long as you are stringing the guitar properly the chipping shouldn't have an impact on tuning stability but if the bridgplate ever splits your tuning stability will be shot.
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Last edited by CorduroyEW at Jun 12, 2017,
#3
Hey Cord, thanks for your reply!

So basically the current way the strings are sitting are fine? And normal restring would not harm the bplate but what would? Like a twisted pin, or something else? What improper methods or studf would cause the bplate to split through sideways (horizontally i suppose, join the holes)? tq
#4
It's kind of hard to explain but I'll give it a go.  Improper stringing means the ball end wedges itself against the pin to stop the string from moving.  To get a visual of what I'm talking about get a two liter pop bottle, a marble, and a bit of rope.  Drop the marble in the bottle and thread some of the rope into the bottle.  Flip the bottle so that the mouth is facing down and then pull on the rope.  The marble will wedge itself against the rope and the bottle and stop the rope from being pulled out.  This is the same concept behind what is going on inside an improperly strung guitar and it puts outward pressure on the bridge plate causing the plate to split.  You know you are stringing the guitar wrong if the pins start to lift when you tighten them.  If you have to hold the pin down while you tighten the string the 1st time the string isn't hooked under the bridge plate.  Another indicator that you have done it wrong is if your pins are getting stuck.  They get stuck for the same reason the rope in the bottle get stuck.  The ball end is meant to be a hook not a wedge.  Wedges stay stuck even when you relive the tension but hooks lose their grip once tension is released.  Finally if you are seeing the tips of your bridge pins deform over time that means you are stringing it wrong.

Judging from the photo's you have posted I would say your guitar is currently strung properly.  The ball is pushed forward by the pin and pulling against the plate rather than the pin.  I can also see that there is some deformation on the pins so it has been improperly strung at some point in time.  Many modern guitars have notches in the bridge pins and don't have them  in the holes that the pins go into which makes proper stringing of the instrument very difficult.  If your guitar doesn't have notches in the holes of the bridge I suggest you cut some with the blade of a jeweler's saw or jeweler's file.  If you are not sure what notches I'm talking about look closely at the photo's in the link I provided.  You can seen them on both the external and internal photo's.

Ps you are correct that in your case the split would connect the holes.  Splits almost alway run with the grain and this guitar already has splintering running along the grain so it simply makes it more likely to happen.
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Last edited by CorduroyEW at Jun 12, 2017,
#5
Mhm, I know this. Wedging the pin means the ball end rests on the top tip of the pin instead of against the side of the "trench" of the pin and the bridge plate, correct? Which would result in the pin exerting backwards/outwards pressure against the edge of the bridge plate wood its resting on, causing it to split?

As well, the notches, do you mean the small cuts aft of the pin holes that allow the string to arch forward a little? Like my Sigma, in the image attached below :


and this is what the Swing's bridge looks like, including the bridge pin,



if they are I could definitely do up some notches, but what will they help? As in, what's the purpose? And is the bridge pin too deformed to be used safely? (i dont think it is haha)
tq
Last edited by AORNova at Jun 12, 2017,
#6
AORNova  You can harden any unfinished wood surface with, "Crazy Glue". (Cyanoacrylate), those pin holes and bridge plate are certainly no exception.

In fact, with even very large radio controlled airplanes, the wings can be installed using maple blocks and 1/4" nylon bolts, which are then drilled & tapped (!), and the threads hardened with CyA glue.

You have to be extremely careful when wicking the glue into the pin holes, so you don't get any on the guitar top. You can't put anything on the top to protect it, as the CyA will either stick it down permanently, or wick under it and stain the top.

So, it's a delicate operation but it does cure the issue, pretty much once and for all. If you're wondering, any "changes in sound" this treatment makes, should be, (and IMHO), imperceptible.

Some of these types of glues come with a fine gauge extension nozzle. Those that don't, can be wicked down something like a tooth pick.

You do need to practice the procedure through several dry runs, and a second pair of very steady hands would likely be of great benefit
Last edited by Captaincranky at Jun 12, 2017,
#7
Captaincranky
The CA glue, where would I place it? Through the top of the pin hole? Or reach under and dab it on the underside of the bridge where the splintering is?

I don't quite get you, because if I wick the ca glue down from the top, it won't harden the place where the splitting may take place, and, if I do it from under the glue won't flow down the nozzle against gravity because i'd be pointing it upwards 😂

tq
#8
How about if I answer the 2nd part first?
Quote by AORNova
I don't quite get you, because if I wick the ca glue down from the top, it won't harden the place where the splitting may take place, and, if I do it from under the glue won't flow down the nozzle against gravity because i'd be pointing it upwards 😂
OK, to do it from the bottom, you would need very small hands, and the guitar upside down. That, and possibly an inspection camera, a light inside the guitar, and a mirror.
Quote by AORNova
Captaincranky
The CA glue, where would I place it? Through the top of the pin hole? Or reach under and dab it on the underside of the bridge where the splintering is?
CyA has extremely low viscosity and surface tension. In plain words, it's wetter than water, and it will wick into any porous surface it might contact.

Think in terms of wicking the glue along a string. If a string has the proper J bend, it runs slightly under the bridge and contacts it. That's where the adhesive has to go, and that's how the wick should be shaped. I'm guessing if you would feel more comfortable, you could position the guitar vertically, head stock down. (Or any angle up to 90 degrees at which you feel comfortable). That would mean the glue flowing "down", would actually be the glue flowing "forward",
from the guitar's perspective. Does that help?

Look, I did this successfully to one of my guitars with it laying on its back. I did get a tiny spot of glue on the top. It wasn't the end of the world. But if you can prevent it happening to you, so much the better. Like I said, CyA is runny, and it will easily saturate and move through any wooden surface it might contact.

FWIW, you won't hurt my feelings if you don't take my advice. I'm quite familiar with CyA adhesives from working with model aircraft. I find it does jobs that nothing else will. For some tasks, even the thin fast setting glues don't dry quick enough, and you have to use them in conjunction with an "accelerator". (That shouldn't be necessary for the task at hand).
Last edited by Captaincranky at Jun 12, 2017,
#9
Yup, I get you, flip her over, support the guitar on either end with something, and from underneath the soundhole reach in and somehow wick the glue in. Tough job..

Plus, I've just unstringed the guitar, and it actually looks much worse now, at least to my eyes..


Should I continue trying to diy fix her up, or get a replacement? I have found a replacement (from a guy who wouldn't mind trading his guitar for mine, and working on the swing himself) with none of this messy bridge issue.
Another plus, the guitar he'll like to trade in retails at $100 more than my Swing.

Yeah.. gonna pop the question in again, worth to diy the underside of the bridge, or get that replacement?

cheers
#10
AORNova Well first, if those are the pin holes, what's the white stuff in them? Or is the light fl;at enough that I'm seeing the side of the pin holes and they just look "full"?

But, more importantly, that doesn't look that bad to me. But by all means, hold out for a second opinion.

EDIT: Plus I have no idea how I managed to give you the impression that you should apply the glue from inside the guitar. Perhaps my ability to communicate in English isn't as good as I thought.
Last edited by Captaincranky at Jun 12, 2017,
#11
Captaincranky The white stuff is the wood of the bridgeplate, I think. Pretty sure its the lighting.
Yeah, I kinda don't get what you mean about wicking the ca glue in, it's kinda complicated the way you're explaining it, and I probably misunderstood by a long way
#12
Quote by AORNova
    Mhm, I know this. Wedging the pin means the ball end rests on the top tip of the pin instead of against the side of the "trench" of the pin and the bridge plate, correct? Which would result in the pin exerting backwards/outwards pressure against the edge of the bridge plate wood its resting on, causing it to split?

Exactly.  You get backward pressure from the pin and forward pressure from the ball end causing the plate to split.
As well, the notches, do you mean the small cuts aft of the pin holes that allow the string to arch forward a little? Like my Sigma, in the image attached below :


 and this is what the Swing's bridge looks like, including the bridge pin,


 

Yes, those notches you see on your sigma is what I am suggesting you create on your Swing.
if they are I could definitely do up some notches, but what will they help? As in, what's the purpose? 

The notches make it easier to position the ball end of the string correctly because it creates a space for the string pushed into by the pin.
And is the bridge pin too deformed to be used safely? (i dont think it is haha)
tq

It is safe to keep using the pins you have but a new set of pins would make stringing the guitar easier.  If you do replace the pins you may want to consider getting something other than plastic because the harder the pin the easier it is to correctly string the guitar.  Wood pins are not much more expensive than plastic and wood pins are much harder than plastic.
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#13
Thanks for the help Captaincranky !
It's all good, I've found a guy who does luthiering, and wouldn't mind fixing the entire bridgeplate issue, in exchange between a Cort guitar of similar price. Seems that he doesn't mind, and he just loves his hobby. Win win, I get a good Cort guit with no issues, and he gets something to work on.
But I'll keep your advice in mind, and use it if it need be in the future! Many thanks!

And as a little treat, here's the Sigma's bridgeplate. Absolutely brilliant condition. Must be me being too careful and pampering her too much, haha.



Cheers!

(If there're any issues with the Cort I'll update this thread, if not, i'll leave it at here! Thanks!)
Last edited by AORNova at Jun 15, 2017,
#14
AORNova Just an FYI to anyone concerned about this issue, a Mitchel's Plate Mate is an option as a repair.  Google 'brass bridge plate saver'.  Haven't tried one, but it sounds like a reasonable idea, especially for vintage instruments.
#15
juhrmann 

3/16"brass washers also work at martin string spacing, but have the disadvantage of being messy to work with. I made a brass plate out of shim stock that was small and lighter than the Stewmac (Plate Mate) version. I would say it weighs less than a single brass pin.
#16
I can think of ways of applying CA that involve holding a piece of non-stick plastic (eg our milk bottles) against the bottom of the pin hole, and carefully dripping the glue into the hole. The plastic wouldn't have to seal it, it would just need to make the glue spread across the width of the hole and into any cracks. The glue residue could be cleaned off with a pin hole reamer or rattail file. - I have one that is just the right size. I would put a drop sheet in the bottom of the guitar to catch any drips
#17
Quote by Tony Done
I can think of ways of applying CA that involve holding a piece of non-stick plastic (eg our milk bottles) against the bottom of the pin hole, and carefully dripping the glue into the hole. The plastic wouldn't have to seal it, it would just need to make the glue spread across the width of the hole and into any cracks. The glue residue could be cleaned off with a pin hole reamer or rattail file. - I have one that is just the right size. I would put a drop sheet in the bottom of the guitar to catch any drips
I had envisioned a similar strategy involving thick aluminum tape, of the type you might use for repairing a roof gutter. Sticjk it on the bottom of the bridge, pour in some CyA, wait a few seconds for it to penetrate the wood, then yank the tape while it's still a bit wet. And yeah, CyA won't stick to some plastic, so a freezer bag taped to the bottom of the guitar, with a few paper towels on top, of it would take care of any potential spills

I just got really tired of being misunderstood. I felt like I was spouting the ravings of a madman, so I just gave it up.
Last edited by Captaincranky at Jun 18, 2017,