Screw lenght and sound

[orangedrop]

Maybe this is a stupid question - I understand that the material in the screws (ie HB PU) will affect the sound but what about the physical properties?
Does screw length and thickness affect sound?

[Possum]

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Yes. You can cut off the bottoms of your screws and you will get a brighter tone, some people actually do this. Head size changes how the strings are sensed and heard. The alloy of the screws changes how treble and bass are reproduced...

[belwar]

+1 to what possum said.

Changing the length of the screws (and to a lesser degree, the alloy) alter the inductance of the coil. There are alot of really bad sound screws out there.

[frankfalbo]

It also changes the way the magnetic field looks at the top of the coil, how it passes through the outer edge of the coil, etc.

[Possum]

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Alot of that has to do with head shape. Before Guitar Jones screwed everybody and disappeared, the screws you'd get from that source were really small and just a hint of a slot on top, very difficult to use. I wouldn't say they were "bad" sounding, just that the small heads don't sound the way I want. Its like the difference you hear in vintage size tele magnets vs. the thinner CBS era ones, very noticeable. The screws I'm using now are close to real PAF screws, and have a batch on the way that should be closer. These have much larger heads and big slots. These are very different. Leo Fender, I believe it was, actually patented pole screws with large heads and deep slots. What happens with those is that each side of the screw head acts as a single magnet pole, so you got flux spewing out two small poles and of course they repel each other. If you have Erlwine's books, he has a photo showing how the pole heads were arranged from the factory when the old 'bursts were new. Basically they are about a 30 degree angle from having the slot line up with the string, so guess they were aware that having the slot run the same direction as the string wasn't a great idea. Anyway Leo patented the idea of tone control by slot position, I think this was for bass pickups, not sure I remember right. The cheapie screws have threadcutter ends on them, that looks like a slice taken out of the length on the end, I hate those. Some screws have narrowed ends called a header point to help ease the screw into the hole. Not a fan of those either and PAFs didn't use that. Screws are a complex subject, there is alot more that I don't know about them, different types of threading etc. Dealing with fastener making companies is fun, cough cough...

[orangedrop]

Thank you for your excellent replies.

Concerning length - If I shorten the screw, the sound will be brighter?
More focused magnetic field? Less magnetic field interference from the botten of the PU?

[Possum]

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the flux has a shorter circuit to go through, less metal. Hope you have a spare set of screws. I've seen PAFs that were used in lap steel guitars, actually its the first use of them and Gibson cut the screws off at the bottom, ouch. Because the pickup wouldn't fit in there with screws sticking out, Seth Lover probably had a hissy fit over that one...

[Achiles]

Possum,based in slot angle "EQ" ,what do you think about allen head screw.
Something like a tubehead screw.
see Fury pickups.
Welcome to the Fury Guitar Web site

[David Schwab]

Seth Lover probably had a hissy fit over that one...

But remember, Lover didn't want the screws sticking out of the bottom... or screws in general.

[Possum]

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I really don't know anything about allen head poles, thats metal head territory. I've seen the patent for the tubular pickup poles, seems kind of gimmicky to me, I'd like to hear sound clips....