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Most bridge pins you buy at a store or come with an instrument come fluted. I have read on here that fluted pins are a good way of damaging your guitar but with no reason explaning why. So i'm asking, why? I have used both before. I want to say that i always have cut slots in front of my pin holes because I realized a long time ago that it was easier to get the string ball to sit right and not get caught on the pin tip and i felt it helped with the break angle over the saddle.

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Guitars, guitars and more guitars.

Here is an example of the conventional solid pins. It's how pins were pretty much always made up until the 30's and 40's.



I've never measure the slot depth precisely, but I would approximate the ideal slot depth at the bottom of the hole to be half the diameter of the ball end, plus half the diameter of the wrapped string. When cut this way with a solid pin, the pin will push the ball end in to position, at which point you should be able to remove the pins once strings are up to tension and the strings should stay in place. There will be only direct upward pressure of the ball against the plate, and no significant force pushing it back toward the hole. Excuse the poor sketch from a previous discussion, but if anyone has the software to make a better drawing I would love to have one.
Disclaimer - In this sketch from months back I wasn't thinking quite right and didn't even draw the slot to the ideal depth, but you can imagine what I meant.



Now when injection molded plastics came available, companies were quick to realize they could save much time in making slotted pins, saving a step in labor. This is what we ended up with.



Now what we have is a number of issues immediately. First is that the ball end can now fit in to the slot on the pin and rest directly against the corner of the pin hole. Second and more significant is that the string is bent sharply at the bottom of the hole, creating a good deal of force pushing directly back against the pin. Again, a poor drawing here, but bear with me.



So what happens next is something we all see. Pins begin to wear and dent, and the ball end starts to tear up the edge of the hole at the bridge plate. Here's an example of early stage degradation.



This creates a new force in the picture. The ball end with its round edges and effective tangents when forced in to a hole smaller than it, will begin to act as a wedge. As it is pulled up in to the hole, it will push more directly outward against the pin and edge of the hole, increasing it's ability to cause damage. This snowballs even further when it either cracks the bridge plate, or makes it's way through it to the spruce. At that point there is really nothing to hold it back, and it comes right up to the bridge in no time.



I wish I had some pictures, but for perhaps the first time I can remember in years, I don't have any bridge plate repairs in the shop this week. I had two picked up last week, but none to shoot right now. Oh well, few days go by that I don't have one come in, so I can get some real world shots soon I'm sure.

Here's a 1935 Martin that came in last week. Solid pins originally, and though only four originals were left the owner had the sense to put the slotted replacements in backward.



72 year old guitar, and the maple is slightly compressed. If you can find a guitar half that old with slotted pins that isn't either ravaged or already repaired, you're lucky. You just never see those problems though with traditional solid pins, unless of course someone has replaced the pins with slotted ones which is a double whammy.

You may also note the fourth pin in the above photo is missing. This is testimony to how the strings hold in place well enough with the pins removed. They hold so well in fact, that the owner apparently thought they could substitute one of their pins for an impromptu endpin. Looks like it went in a bit too far though.



Now when the plate gets worn but the damage does not extend in to the spruce, StewMac's bridge plate repair tool is an absolute wonderful thing. Of course I always fit the bridge for solid pins after doing this.



If the damage is up in to the spruce, but the plate is not cracked and the bridge is not split or lifting, then I will often use the more traditional cap.



Or if the repair coincides with the bridge having to come off (which it often does) you can plug from both sides with the StewMac plug tool.



So, solid pins are good. Slotted pins are bad. It's understandable the damages were unforeseen in the 40's when the transition happened. By the time the problems became more widely recognized it was probably already the 70's. Factories in that era and with those production numbers weren't about to switch back to a slightly less efficient production method. At that point they were already a standard, and it's unlikely that many folks buying instruments then even knew solid pins ever existed.

Some people recommend using slotted pins because of their availability, and simply turning them around. This is fine for a builder/owner, but I think it greatly overestimates the knowledge and attention span of the average guitar owner. Eventually, either when the guitar is sold, or more likely when the owner forgets, the pins will start to be used slot forward. This is a worst-case scenario, because it is as though the bridge plate is already perforated, leaving little material for the ball end to have to chew through before it does serious damage.

In summary, please disregard all that I have said above. I am a repair man. If people keep using slotted pins, I will always have plenty of business. Long live the fluted pins!!!

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Eschew obfuscation, espouse elucidation.

Mike you got it right buddy, non-slotted is clearly better and the better break angle is yet another reason that I have not heard until you brought it up.  Good thinking!

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Ann Arbor Guitars

What David just posted is the definitive guide to this question and the most comprehensive explanation that I have ever seen.

Thanks David!!!

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Ann Arbor Guitars

David great pic's. They make it easy to understand what problems can occur. All these years i thought they started using sloted for some inovative reason i just couldn't figure out. Here they just did to save a buck on manufacturing. Thanks mike

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Guitars, guitars and more guitars.

Nicely done, David. Thank you.

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"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

I don't use slotted pins anymore for the same reasons.
I use a small burr in the dremel to rough out the bridge slot and them finish
up with needle files. Takes only a few minutes.
-C

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Freeborn Guitars
and home of BeauGuard©

Great explanation David I have been convinced for years but If was not I would be now

Are many people making unslotted pins or are we stuck with turning the pin backwards and hoping the customer continues to do so?
-j.

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“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

Stewmac's wood or bone pins are available in slotted or unslotted

J also Louis (OLF screen name Louis4052) will make you custom pins out of the material of your choice.

Louis made these beautiful BRW "stumpwood......" 3 degree, unslotted pins for me.

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Ann Arbor Guitars

Aren't all Stewmac's unslotted 5 degree pins?  I'd like to see some discussion on the merits of 3 vs 5.

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A higher purpose for wood.
Rich Smith
Issaquah, WA

Jeez
Can you go into a bit more detail, ????

Nice explanation!
Thanks
Charlie

Yes Stewmac's pins are 5 degree

Frankly I doubt the difference really amounts to much as far as wear is concerned. The steeper the angle the quicker the pin will reach release point but even that is really manusha in my opinion

Also the steeper the angle the more pin surface area is contact with the bridge and bridge plate.

The main reason for 3 degree pins' existence is to have a smaller pin head. Since we MUST have at least a 3/16" exit hole, the less taper, the smaller the head, more taper, larger head.

there's always a reason....

I really don't have any thoughts on this issue. My strings are nylon and the end is knoted with a bead. The strings are then inserted from the bridge plate up through sting size holes and then over the saddle.

I just wanted to say thanks to David Collins for some really great information. Very well done!

Philip

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aka konacat

If you think my playing is bad you should hear me sing!
Practice breeds confidence and confidence breeds competence. Unfortunately, I'm stuck in practice.

Wow! Was that thorough. Thanks for making that REALLY clear.

Merry Christmas
Danny

I said I would post some damaged bridge plate photos when the next one came in, so here goes. This may not be the best example, but not atypical either. Massive plywood 70's Gibson double-X bridge plate that came in this afternoon.



Someone had already slotted the bridge and plate, and whether they advised the customer or not to use the pins in reverse we'll never know. In any case, they didn't. Don't ask me where the toothpick comes in, I haven't a clue.

The bridge had already cracked along the pins once, and a previous repair tech had glued and filled the crack a couple years back. Unfortunately they paid no attention to the underlying cause, that being the ball ends pulling up through the plate. This went unattended to, and in just a couple years the symptom of the cracked bridge came back. Now it needs to be replaced, along with a proper bridge plate and top repair.



Here's a shot of the damaged pins, and a good view of the misguided slots in the top.

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Eschew obfuscation, espouse elucidation.

David I also want to toss my "thanks" into this thread. Awesome work with the explanation and, like Hesh, the best explanation I've ever seen.

Thank you.

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Eagles may soar, but weasels don't get sucked into jet engines.

Yikes!

Reminds me of the propaganda pictures of smokers lungs they used to show us in health class to scare the bejeebers out of us. I never took up smoking and I'm turning my pins around tomorrow!

Thanks David! Great explanation!

J.R.

(Until I can get unslotted pins that is...)

Great  tutorial, thanks Collins! Has anyone used one of those bridgesaver devices that I see for sale at some places? They are a metal plate which supposedly will protect the bridge, pin holes, and top.

I think those plate mates are a fine quick fix. They're completely
unnecessary if the pins and slots are done well to begin with, but for a quick
fix on a torn up plate they seem just fine. Of course they add unnecessary
mass, but for most average guitars I think it is not enough to likely make a
big tonal difference.

To be honest I've always disliked them not for any good reason of function,
but rather because of the snake oil baggage that they bring with them. Had
they just advertised them as a repair for damaged bridge plates I would be
fine with them. When they are advertised as some tone enhancing device
however, it nauseates me just enough to be prejudice against supporting
them.

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Eschew obfuscation, espouse elucidation.