Slotting a bridge

[Peter Wilcox]

You really don't need bridge pins, as has been mentioned before. Slot the holes, string and tune the guitar with pins (to make sure the ball ends are properly placed), then take the pins out - the strings will stay in place. The slots may need to be a little deeper (to reduce anxiety), and the bridge plate might deteriorate a little faster without the pin keeping the edge of the hole from compressing.

[redir]

Originally Posted by charles Tauber

We live in what has been called "the Information Age". Never before have we had such easy access to so much information: we are being buried beneath it.

Very often, the information with which we are presented is diametrically opposed: one person presenting the information states it is black while another presents the same information as being white. Distinguishing between what is good or valid information and what is not has never been more difficult: it is increasingly difficult to determine who is and who is not an expert. All of us are experts and none of us are experts.

Faced with so much information - and so much opposing information - many who lack the rational basis to determine which is good/valid information and which is not simply give up and chose to believe whatever information they want to believe is good and valid. Truth, for example, becomes whatever one wants to believe it is: objective evidence becomes irrelevant. In modern parlance, anything that doesn't align with what one wants to believe becomes "fake news".

Suppose five people state, as Jon does, that slotting pin holes is "bad" and five other people state, as some of us have, that slotting pin holes is good. How does someone reading this discussion determine what is "the truth" regarding slotting pin holes, or not? Do they just throw up their hands and say, "Well, some say it's good and other's say it's bad, so it is unknowable and the truth is whatever I want to believe, whatever appeals to me"? How does a reader determine who's information is valid and who's is not? By what criteria do they determine that? Jon has 40 years of engineering/manufacturing experience. John has 40 years of guitar making and repairing - he's also a mechanical engineer. Who's "right"? Since each is presenting diametrically opposing information, they can't both be right. Both are "experts" in their respective fields - one in manufacturing et al and one in guitar making.

Often, people get tired of the issue and just simply chose whatever appeals to them, either because it is easier, or just because they want to believe a particular view point and don't want to be burdened by objective evidence. For many, objective evidence to support information is irrelevant: I believe it because I want to believe it and it must, therefore, be true.

Well said. To add to that there is the concept of the 'Backfire Effect' and 'Dunning Kruger.'

[John Arnold]

If the bridgeplate is damaged from the string balls after slotting, I believe it is because of one or all of the following:
1) The slotting was sloppily done, allowing too much clearance around the string. The proper way to do this is to fit the bridgepin first (with a tapered reamer if necessary), then cut the slot, testing the fit with the selected string and the bridgepin as the slot is gradually enlarged. Once the string and pin can be installed with the pin fully seated with minimal force, stop enlarging the slot. This goes to the concept in my original post....slots fitting each individual string. That is not usually done with slotted pins, since most adhere to the notion that pins should be interchangeable on the different strings.
2) Improper pins were installed. Martin used slotted thermoplastic pins in slotted bridges for over 40 years....plenty of time for damage to occur. I have literally repaired hundreds of them. The sad irony is that many of these guitars were slotted deep enough to install superior unslotted pins from the get-go. If that had been done, the guitars would have fared much better, like their prewar counterparts.
3) The bridgeplate is made of soft maple, or other soft wood. Maple varies widely in hardness; much of it is not hard enough to stand the pressure from the string balls. I have seen this too-soft maple on very expensive guitars, including Martins.
4) The pin holes were drilled without using a backer block, chipping out the bridgeplate. Once again, I see this on guitars at all price points, including Martin. I have actually witnessed this poor practice at the Martin factory. One of the advantages of maple is that it doesn't chip like some harder, more brittle woods, but it still happens.

I have used all manner of hard woods for bridgeplates.....ebony, rosewood, pernambuco, snakewood, and black locust, just to name a few. If I am not using antique old growth sugar maple (for restorations or vintage recreations), I prefer black locust. IMHO, its combination of hardness, stiffness, and density make it an ideal wood for the purpose. Locust adds a bit of sustain and punch, but is not overly dense or stiff as some of the other mentioned woods can be.