1.94" steel spacers (screw keepers)

[Corona Blue]

Hi everyone-

I've just been making my first handful of PAF and early P90 sets, trying to get beyond some of the problems of the standard "off the shelf" parts available these days. I've been using mostly stuff from Mojotone, but I find that things like the 1.94" PAF/P90 steel spacer to be problematic. The spacer seems too lightweight and a bit too thin dimensionally (vertical height). This creates mechanical oscillations that I have to dampen out with tape shims or wax potting.

I have read through a good many posts here, going back to around 2006 or so, when the now senior members were struggling with these same issues. I'm just wondering if anybody is presently making better quality metal spacers and base plates for the 1.94" spacing and if I can purchase a handful for my own uses. I'm a hobbyist, I don't make many of these, just a few for myself and friends, but I would really like to get it right! (I'm old enough to have owned a few guit's with these pickups, and remember their unique sound and feel... old enough to wish I never sold any of them!).

Thanks in advance,

Allen

[Corona Blue]

Uh oh... did I say something wrong??? 48 views, no replies...

[Magnut]

I can't suggest any other vendors but I will suggest not using the keepers. Not everyone uses them and they are not completely necessary. Not using one on a humbucker of course means using a slightly wider magnet. Of course a P90 doesn't have any such issue.

Mojo offers a few different keepers. I have found the eight hole to be different material than the ten hole. You may want to try switching which one you use.

[Lpone]

been there done that - hint: stewmac

[big_teee]

been there done that - hint: stewmac

The Stewmac Kits had a Keeper and Spacer the same thickness as the magnet they provided.
So with other Keepers and spacers, unless you tape or add some addtl. thickness to what is supporting the edges of the bobbins.
You end up with the magnet edge of the 2 bobbins higher than the outside edges of the 2 bobbins.
Causing the bobbins to lean and gap. What do other Winders do to correct this?
I end up shimming the outside edges to match.
Terry

[Corona Blue]

The Stewmac Kits had a Keeper and Spacer the same thickness as the magnet they provided.
So with other Keepers and spacers, unless you tape or add some addtl. thickness to what is supporting the edges of the bobbins.
You end up with the magnet edge of the 2 bobbins higher than the outside edges of the 2 bobbins.
Causing the bobbins to lean and gap. What do other Winders do to correct this?
I end up shimming the outside edges to match.
Terry

Hey there T!

Yes, this physical leaning is another symptom of the same problem. But when using say a rough-cast magnet from AddictionFX (which is also a bit taller like the old magnets I have seen), when you shim the outer bobbin edges on the screw bobbin (at the fence) you take a good portion of the bobbin's loading pressure off of the cheezy metal spacer and it will oscillate and cause the pickup to go microphonic. But I have had this problem with regular milled magnets as well. I have been fixing the issue by potting just the space below the bobbins, but it takes away a lot of the nicer harmonics too.

I don't think Stewmac has the 1.94" (49.2mm) metal spacers for PAF bobbins.

Allen

[LtKojak]

I don't think Stewmac has the 1.94" (49.2mm) metal spacers for PAF bobbins.

mojotone.com have'em.

http://www.mojotone.com/guitar-parts...ar-49-2mm-1-94

HTH,

[Corona Blue]

mojotone.com have'em.

Mojo Pickup Parts » Mojotone Keeper Bar 49.2mm (1.94'')

HTH,

Thanks LtKojak-

Yes, I am presently using the Mojotone units. I'd like to do better, but looks like I'm on my own.

[Lpone]

I use the Stewmac spacers with Mojotone 49.2 mm bobbins and baseplates, tightish fit but works for me.

[Corona Blue]

PAF Spacers: The Final Frontier...

This will be old news to the senior members who crossed this bridge many moons ago... probably reading this thread with some wry amusement. But since I know Mojotone has a presence here, and because there are some newer people who may be interested, I thought I would post a little "show and tell."

I dissected a couple of PAF variants I had handy, just to see what is being used for a steel spacer. Apologies for the blurry picture, but I think it is clear enough. Here we have a WB "VTP" PAF and a Gibson "57 Classic" on either side of the Mojotone 49.2 mm steel spacer. The dimensions shown are the vertical height (the axis of the screw holes) X the horizontal width (axis where the magnet face makes contact).





Not to belabor the issue, just for clarification of the problem: most of the 2.5" x .500" milled alnico humbucker bar magnets that I have measured are around .125" in vertical height. They all vary slightly, but that's a pretty good average number. I have measured some of the rough cast bars from AddictionFX as tall as .135" and have found them to vary more than milled bars but, as an average, the .125" number is in the ballpark for them as well.

So assuming a magnet bar height of .125", with a screw keeper height of .115", this leaves a .010" gap somewhere under the screw bobbin and the keeper will likely oscillate if not potted or shimmed (and may still do so, regardless). It is interesting that the Gibson keeper is the correct height (.125") but the horizontal width is cut back to .190" (I forgot to measure the Gibson magnet to see if it was a bit wider). Also, both the Gibson and the WB bars have smaller holes and the steel seems different than the Mojo. I haven't weighed them, but that might be telling. The WB has a flat bottom and slightly rounded top, appearing to be stamped and sheared. The Gibson unit looks like it possibly was milled (very uniform).

Yes, doing away with the bar would be the practical solution. Yes, potting or shimming might possibly mitigate the problem. But why even use the 49.2 mm bobbins if you're not going to try to go all out and make an "as built" PAF?



Regards,
Allen

[big_teee]

Hey Allen:
Either you are much pickier than these other Professionals, Or Mum is the Word!
B_T

[Corona Blue]

Hey Allen:
Either you are much pickier than these other Professionals, Or Mum is the Word!
B_T

LOL!! Yeah, you hearin those crickets chirpin too??

Oh well no worries here.

Allen

[copperheadroads]

I'm doing a rewind on a 1956 p-90 right now & its keeper is .130" thick & magnets are .133"

[Corona Blue]

Thanks CHR-

Better watch yer back... you've broken the blood oath!! Might find a horses head in your bed in the morning!!



But thanks for being a stand up guy. Feel free to post pics, but you might want to do that ANONYMOUSLY... (nod nod wink wink)

Best,

Allen

[copperheadroads]

hAHa It has a turn per layer of 3+how much money is in my piggy bank & the magnets are gaussed 5000 a piece