1/2 vs. 3/4 inch polepiece screws

[kevinT]

I received a sample of 1/2 inch length fillister head screws to try out. I have them installed in the pickup but i haven't had a chance to test for sound. They fit nicely into the bobbin but without the 1/4 inch screw excess coming out of the bottom of the baseplate.

I am wondering what effect a 1/2 inch screw will have on the magnetic field as opposed to the 3/4 inch screws which are normally used.

My initial thoughts would be that it would focus the magnetic field more, and reduce any eddy currents. I'm i correct or incorrect in this assumption?

Has anyone else tried the 1/2 inch polepiece screws?

Any comments are appreciated.

[corduroyew]

Once I ground 1/4" off the polls of one of my pickups. I didn't really "test" so that I could measure results, but I do think there was noticeable lift in the resonate pitch when I reinstalled the pickup.

[madialex]

I think Wolfe uses some in some of his pickups, or at least I have seen a picture that looked like they were barely coming out of the bottom of the base plate.

[David Schwab]

I cut the screws shorter on the few humbuckers I made. I cut them so they just protruded the base slightly (maybe an 1/8").

I didn't notice any ill effect on the tone. There was a reason I did it, but I can't remember what that was at the moment! Probably to not "waste" any of the magnetic field back behind the pickup...

[Zhangliqun]

I didn't notice any ill effect on the tone. There was a reason I did it, but I can't remember what that was at the moment! Probably to not "waste" any of the magnetic field back behind the pickup...

I had heard that this increases output some, the theory being pretty much what you said -- no (or less) "waste" of magentic field below the baseplate, which concentrates the field more.

I laughed at the idea first, but when I ground some down, there is noticeably more punch in the upper mids.

[David Schwab]

Well it makes sense... having the flux field wrap under the pickup serves no purpose. Having it extend too far over the pickup serves no purpose either. You are just wasting energy. This is probably why horseshoe pickups sound the way they do... the shoes confine the field and focus it around the strings.

Leo Fender made some changes to his pickups for G&L, and in the patent he writes about focusing the field right over the pickup, and keeping it from behind. He did this with a U shaped shield under the pickup.

But in the end it's all about how the pickup sounds.

[Joe Gwinn]

I had heard that this increases output some, the theory being pretty much what you said -- no (or less) "waste" of magentic field below the baseplate, which concentrates the field more.

I laughed at the idea first, but when I ground some down, there is noticeably more punch in the upper mids.

I suspect that the effect is due to the reduction in eddy-current loss due to the reduction in nearby metal mass. Steel is particularly effective in causing eddy-current loading.