SE Holcomb with a crooked bridge and no help

[Mozzi]

That surprises me. Why use humans when the CNC can do it better?

CNC is used for all the big holes and cavities. Finish would clog up the small holes and would need to be redrilled anyway so its pointless to do these pre finish. CNC is used to get a body to shape and do the basic routing necessary that templates would of been used to do. Templates were not used for the small holes things like stopping the tuners from rotating, fitting the pick up rings, drilling through the cavities for the wiring and the output jack etc. After a CNC has been used to get the body and neck into the rough shape and carve, with all the cavities (pickups, electronics, trem) and any 'big' holes (6 tuners, tuner-o-matic post holes, pot/switch holes), the rest is totally done by hand. They have a jig made so that the output jack is drilled in exactly the same spot every time.

Any small holes are not drilled because they would fill up with sawdust from all the hand sanding and clog up with the finish too so would still need to be hand drilled when the guitar ends up at 'assembly' - the people that fit the tuners, the pickups, etc would drill the holes needed for those screws.

 

[jak3af3r]

Has anyone in the "CNC does it better" or of the opinion that CNC doesn't deviate actually machined anything with a CNC machine (milling, lathe, etc?)

I've worked with similar machines as what PRS uses and some beyond what woodworking would require and even those have a tendency to deviate slightly because of coding issues, electrical problems, not properly warming a machine before use, stepper motors skipping a step or series of steps. It's amazing the machines are as accurate as they are to begin with.

Most commonly I had parts out of tolerance because a tool would begin to wear beyond its usefulness.

 

[Mozzi]

Has anyone in the "CNC does it better" or of the opinion that CNC doesn't deviate actually machined anything with a CNC machine (milling, lathe, etc?)

I've worked with similar machines as what PRS uses and some beyond what woodworking would require and even those have a tendency to deviate slightly because of coding issues, electrical problems, not properly warming a machine before use, stepper motors skipping a step or series of steps. It's amazing the machines are as accurate as they are to begin with.

Most commonly I had parts out of tolerance because a tool would begin to wear beyond its usefulness.

I guess it depends on what you are making with a CNC machine. With a guitar made of wood, the tools being used to machine are likely to be much harder and therefore wear is not going to be significant - over time maybe but I doubt its deteriorated, become blunt after a week or even a month. Tolerances too aren't necessarily going to be incredibly small - like to the nearest thousandth of a mm and, in the case of shaping, only a 'rough' cut because its going to need sanding by hand to remove the tool marks. Even the cavities aren't necessarily needed to be exact and to the thousandth of a mm accurate. If something does go badly wrong, its very early in the production that its a minor loss - inc all the man-hours that its occupied. Its far worse if something drastically goes wrong during the final test phase, dropping it and cracking the neck for example.

I think it does depend more on the materials you are working with and the accuracy/tolerances required. I can see wood being less of an issue than metal and building a guitar that is still going to have a lot of sanding done having a higher tolerance threshold than other products.

 

[Alnus Rubra]

If I remember correctly, the CNC machinery at Maryland is designed for metal milling. So therefore it’s probably pretty hardy.

Hopefully the OP gets the guitar he wants.

 

[jak3af3r]

I guess it depends on what you are making with a CNC machine. With a guitar made of wood, the tools being used to machine are likely to be much harder and therefore wear is not going to be significant - over time maybe but I doubt its deteriorated, become blunt after a week or even a month. Tolerances too aren't necessarily going to be incredibly small - like to the nearest thousandth of a mm and, in the case of shaping, only a 'rough' cut because its going to need sanding by hand to remove the tool marks. Even the cavities aren't necessarily needed to be exact and to the thousandth of a mm accurate. If something does go badly wrong, its very early in the production that its a minor loss - inc all the man-hours that its occupied. Its far worse if something drastically goes wrong during the final test phase, dropping it and cracking the neck for example.

I think it does depend more on the materials you are working with and the accuracy/tolerances required. I can see wood being less of an issue than metal and building a guitar that is still going to have a lot of sanding done having a higher tolerance threshold than other products.

Wood tools aren't and harder than metal cutting tools like carbide. They'll either be the same or softer as wood is typically a softer material. The silica content of wood is what wears tools down and can do so after a few bodies have been run. In particular the tool that has the potential to wear the quickest would be one that is fully engaged (180 degrees of cutting action at a time) which is a possibility on the outline cut provided bandsaw work isn't close or clean. Even then you run the risk of a tool dulling and cutting a curve wide or slightly crooked and when it goes in a form everything else becomes crooked.

Then if you wait to drill bridge hole until after the body is finished you have all the possibilities of crooked bodies, over-sanding, under-sanding, and finish thickness that could cause the body to sit crooked in a form while a machine drills.

On the matter of metal milling, I've seen a brand new, recently calibrated, multi-million dollar machine drill a straight programmed hole crooked because of the shape and density of the metal pushing the drill inside the material.

I can't say why exactly the holes may be crooked on that body. I'm more curious as to how that passed QC along the way. And if it were mine and it played better than all the other guitars I had, I'd keep it.

 

[Steve Insley]

I kinda wanted to see how this played out from the OP, but after "PRS are sending another one" he didn't say if he was happy with it or if it was the same as the first.

FWIW, I have had three in my possession at the same time after not being entirely happy with aspects of the first that came from an Internet order. I can tell you that the bridge is "crooked" at the exact same angle on all three, so it seems to be that's just the way they are. Sure, if you're really looking it's noticeable, but it's no biggie from a playability point of view. All three guitars measure 145mm from neck to bridge edge at the bass side and 146mm from the neck on the treble side.

My issues are more that the neck binding effect (as it's painted on - it's not real bindng!) is applied pretty poorly on all three. Application of the tape mask before spraying is clearly done by hand, and not particularly carefully. Two of the three guitars also have a neck heel that's worn on one side, making it look like it's not flush with the pickup ring, as per the OP's other observation. There's also yellow staining on the white paint on the neck in places and there is a very slight rough lip/edge just below the fret ends on the "binding" on the side of the neck - which too looks yellow or dirty. This is noticeable to varying degrees on all three guitars.

In the end, I am choosing one of the three to keep. None are perfect. PRS Support told me that this is all "within tolerance" for an SE. OK, that's what £900 quality looks like from PRS - not quite as good as you would get from an equivalently priced Ibanez (I have many) or Fender but there you go. I'm keeping the guitar because it looks nice on the stand, it plays well (or it will when I replace the gawd awful nut), the pickups are KILLER and it makes me smile! I can live with imperfections at the heel of the neck and the "wonky" bridge.

But seriously PRS, the nut that comes on these things is criminally bad. It's worse than on a $99 Chinese made no-brand guitar you get off eBay. I mean, how hard would it be to actually cut it so it fits the neck and the strings actually fit in the grooves? It's like someone found some old scrap plastic in a skip and went "that'll do". Put a better nut on them and charge an extra £20.... you'll sell so many more of these!

 

[Allstarrme]

There’s an easy fix to that bridge problem

 

[Steve Insley]

There’s an easy fix to that bridge problem

Haha - not exactly "easy" but a replacement bridge would certainly do the trick. Not sure about an Evertune on this guitar though as you kinda lose that Baaaaooooww on the low-tuned strings that I like for that djenty sound. But, if you're a jazz man, then sure! :-D