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Magnets & Copper Wire: A Pickup Building Thread

#361
Bruce Johnson said:
Do you actually want a shiny polish, or just an even satin finish?

Like T Bone said, a vibratory machine is better at deburring the edges and putting on a satin finish. Not so good on polishing flat plates. By the time you got it shiny with soft abrasive, it would really round off all the edges.

If a satin finish is okay, you could use sandblasting in one of those little benchtop cabinet machines. There are many grades of abrasives available. That would be fast and easy to do.

If you want them full-polished, use buffing wheels with common Tripoli compound. Because these parts are flat with all the holes and cutouts, you'll have to come up with some way of holding them while you buff. You have to apply some pressure to buff out brass, and they will get hot. Make up some kind of a handle/holder. Another approach would be to screw a group of them down to wood board, clamp it down, and go over them with a 6" buffing wheel in an electric drill. You'd want to use a fairly stiff buffing wheel, maybe a felt wheel.
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I wanna try getting both finishes. I think that either way, I'd want to deburr, so the vibratory machine is worth a shot for that at least... maybe with corn cob media.

I like the suggestion of using a bigger buffing wheel while screwed to a board. The dremel buff is a little too small, I think.
 
#362
The vibratory machines with corncob media do a great job of shining up the brass on your reloading bench. But, the brass shells were already polished shiny. They just got tarnished and dirty from shooting. The corncob cleans off the tarnish. Taking brass plates from mill finish up to a polish is a lot more mechanical grinding and rubbing.

Polished vs Satin: The downside to polished brass is that it will tarnish quickly, and it tarnishes in uneven patches and looks ugly. To prevent tarnishing, you have to coat it with a clear finish (I use Sta-Brite) or wax it. And once you've coated it, you have to handle the part carefully to avoid scratching it. And you can't solder to it.

Satin finished brass will also tarnish, but mostly gets duller, more evenly.
 
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#363
Bruce Johnson said:
The vibratory machines with corncob media do a great job of shining up the brass on your reloading bench. But, the brass shells were already polished shiny. They just got tarnished and dirty from shooting. The corncob cleans off the tarnish. Taking brass plates from mill finish up to a polish is a lot more mechanical grinding and rubbing.

Polished vs Satin: The downside to polished brass is that it will tarnish quickly, and it tarnishes in uneven patches and looks ugly. To prevent tarnishing, you have to coat it with a clear finish (I use Sta-Brite) or wax it. And once you've coated it, you have to handle the part carefully to avoid scratching it. And you can't solder to it.

Satin finished brass will also tarnish, but mostly gets duller, more evenly.
Click to expand...

Yeah, I'm less concerned with the brass, finish-wise. The stainless, though, is something I want to play around with.
 
#364
I believe you'll need heavier ceramic media, not corncobs or walnut shells for deburring, particularly stainless. Possibly plastic media, which is somewhere in between.

Not really sure about "what shape might work best" - there are many, and I think its typical to experiment and find what suits your parts/process best, but that also seems like a rabbit hole you could send a bunch of money down.
 
#365
I have a fair amount of experience with working both raw brass and stainless steel. When you get to the de-burring or rounding edges stage I suggest you go with more aggressive mechanical means. I de-burr and round over corners with common files followed with a 220 hook and loop disk in a 5" random orbit sander. If everything is sanded to 220 then you can follow with 320 and finer paper depending on what your finished surface needs are.

For actual polishing I use a 6" cotton buff in my drill press spindle and apply "cut and color" compound for either brass or stainless. Spindle speed of 2400 or so works well.

DO make sure you hold the work safely and in away that will deflect it if there's a catch. Experience is the best thing to guide you with the polishing work.

Raw brass or stainless can be easily brought to a mirror-like shine using only the cotton buff and compound.

If you're not looking for a mirror polish you can stop at 320 and go with the vibratory polisher if you're going for a matt or satin finish. You'll find a vibratory polisher will have little effect for de-burring or rounding, even if you use ceramic media.

I usually throw raw brass in my 5 pound vibratory polisher with dry play sand to produce a matt finish.

I follow the surface prep with a 1 minute or less swirl in patinating solution because I love the antiqued brass finish it produces. No tarnishing or uneven coloration following a patina finish. There are several brands of brass solution available.

In the next couple of installments of my build topic "Building a Short Scale P Bass" I'll be detailing making the adjustable bridge and I'll be covering some of those details regarding raw brass finishing.
 
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#366
rudy4444 said:
I have a fair amount of experience with working both raw brass and stainless steel. When you get to the de-burring or rounding edges stage I suggest you go with more aggressive mechanical means. I de-burr and round over corners with common files followed with a 220 hook and loop disk in a 5" random orbit sander. If everything is sanded to 220 then you can follow with 320 and finer paper depending on what your finished surface needs are.

For actual polishing I use a 6" cotton buff in my drill press spindle and apply "cut and color" compound for either brass or stainless. Spindle speed of 2400 or so works well.

DO make sure you hold the work safely and in away that will deflect it if there's a catch. Experience is the best thing to guide you with the polishing work.

Raw brass or stainless can be easily brought to a mirror-like shine using only the cotton buff and compound.

If you're not looking for a mirror polish you can stop at 320 and go with the vibratory polisher if you're going for a matt or satin finish. You'll find a vibratory polisher will have little effect for de-burring or rounding, even if you use ceramic media.

I usually throw raw brass in my 5 pound vibratory polisher with dry play sand to produce a matt finish.

I follow the surface prep with a 1 minute or less swirl in patinating solution because I love the antiqued brass finish it produces. No tarnishing or uneven coloration following a patina finish. There are several brands of brass solution available.

In the next couple of installments of my build topic "Building a Short Scale P Bass" I'll be detailing making the adjustable bridge and I'll be covering some of those details regarding raw brass finishing.
Click to expand...

I really appreciate the input!

I did try ceramic media with the stainless, and yeah... the results weren't all that impressive. I think I'll try what you're suggesting: sanding to deburr, and then likely sand in the vibratory cleaner.
 
#367
Well, I can't help myself...

I made another multi-coil pickup, and I think this design is a keeper.

Each coil is 9960 winds of 44awg. Steel keepers and a ceramic bar magnet, adjustable set screws for poles.

IMG_20201120_191421_998.jpg
IMG_20201120_191422_008.jpg
20201120_192803.jpg
 
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#369
slowburnaz said:
Well, I can't help myself...

I made another multi-coil pickup, and I think this design is a keeper.

Each coil is 9960 winds of 44awg. Steel keepers and a ceramic bar magnet, adjustable set screws for poles.

View attachment 4060633 View attachment 4060634 View attachment 4060635
Click to expand...

Very nice engineering and mechanical work! Now that looks like a good production-ready multi-coil. You might be able to sell those to Wal. Seriously. Or find some other high-end small builder who wants to get into that type of pickup.
 
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#370
slowburnaz said:
Well, I can't help myself...

I made another multi-coil pickup, and I think this design is a keeper.

Each coil is 9960 winds of 44awg. Steel keepers and a ceramic bar magnet, adjustable set screws for poles.

View attachment 4060633 View attachment 4060634 View attachment 4060635
Click to expand...
The only thing that detracts from the aesthetic for me personally are the four screws holding the cover in place. If the cover could be attached from underneath for a cleaner look I would be interested:drool:. Nice job though and kudos for putting the time in:thumbsup:!
 
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#372
Slidlow said:
The only thing that detracts from the aesthetic for me personally are the four screws holding the cover in place. If the cover could be attached from underneath for a cleaner look I would be interested:drool:. Nice job though and kudos for putting the time in:thumbsup:!
Click to expand...
I agree, another idea would be to use black screws to attach the cover. These pickups are quite nice looking :thumbsup:
 
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#373
Slidlow said:
The only thing that detracts from the aesthetic for me personally are the four screws holding the cover in place. If the cover could be attached from underneath for a cleaner look I would be interested:drool:. Nice job though and kudos for putting the time in:thumbsup:!
Click to expand...


I agree that attaching from underneath would look cleaner. I'm sure it could be done somehow, but space is limited... I could see maybe having tube-like structures coming down from the inside of the top which could be threaded, but I worry about the durability of those threads in the nylon.
 
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#374
Bruce Johnson said:
I'm curious about the bobbins. It looks like they are also 3D printed? Did you print them in one piece, or are they upper and lower halves? Any secondary machining operations on them?

This whole pickup shows very effective use of 3D printed parts. Nice work!
Click to expand...

You're right, the bobbins are 3D printed as well. All one piece. Didn't need to do anything more to them... this printing process (HP Multijet Fusion) is really nice and accurate. I did the rectangular protrusions on the bottom so they'd kinda mechanically lock into place in the PCB, and hopefully guard against any twisting when the pole pieces are adjusted. The adhesive should prevent that anyway, but I guess I consider it another preventative. :)

Also, I did the surrounds like this for a couple reasons...

1) I wanted to see if I could pull off the "Wal" look.
2) I also wanted to test whether or not this material would be sturdy enough to be used in this manner.

I think if I ever actually started selling this design, the obvious similarity to Wal pickups would concern me from a patent/trademark perspective... although I don't think Wal has any patents or TMs on the pickups themselves. I know of at least a couple other makers that do this sort of thing and sell them, too.

I'd likely put this into a MM cover, which would be easy enough, as the baseplate and cover currently already fits into that standard route. Plus, it might be a bit much to think that someone would want to put four extra holes in their bass for the surround to take a chance on some unknown pickup maker guy. heh
 
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