Single coil repair

[playas]

Hi guys,

I have a couple of stock singles from a late 80s strat copy. The resistance is low on both, somewhere between 5K and 6K, I don´t have the exact numbers handy. The neck pup is fine, but one of the screw threads on the middle is stripped.

I had put tiny bits of paper between the bobbin base and the cover when mounting it, in order to wrap around the screw to hold it more or less in place. That worked a few times but at this stage I need another solution.

I know that I could probably use something like hot glue as another temporary fix to try and rethread. However if I understand correctly, I´d need to replace the base of the bobbin, completely taking the pickup apart, i.e. the pickup would need to be rewound to fix that issue properly. They are presumably cheap korean made pups. I have no idea what the existing polepieces are but on the assumption that it´s most likely the cheapest material, I would imagine ceramic. Also no idea what type of wire is used.

1) Is that correct or is there a way to replace the base without rewinding?

I have also been thinking about just replacing both of the singles (it´s a HSS guitar). While I am reasonably happy with the sound of the singles, they don´t exactly blow me away. It ocurred to me that maybe it would be worthwhile, in terms of the experience and end result, to buy new bobbin bases and tops, some A3 polepieces and try and re-wind them as I presumably haven't got too much to lose, especially with the middle pup. I haven´t previously opened up a bobbin.

Bear in mind that I would be going into this with the idea of replacement pickups if it doesn´t work out.

2) Would it even be worth trying to rewind them with A3 mags with the resistance being so low? My ideal would be a 50s strat style pup.
3) If so, are there standard dimensions for (non-staggered) strat polepieces and is there anything else I would need to get hold of apart from the polepieces and the flatwork?
4) Assuming it´s not a complete waste of time re-winding them, any other advice?​

 

[freefrog]

*If your single coils are powered by ceramic, their poles are made of steel and there's magnets under their coils. if there's no bars under their coils, their poles are AlNiCo rod magnets.

*Such pickups are usually potted. If they have fiber baseplates, it will/would/should be very difficult to pull them apart without harming the wire. Now, cheap pickups are often wound around relatively soft plastic bobbins (and the stripped screw holes in this case seem to confirm that idea).

*Without knowing how these SC's are powered and if they have plastic bobbins or not, I don't see how to give any relevant advice regarding the rod magnets to use.
But the 5k to 6k range IS typical for Strat single coils from the 50's, FWIW... https://guitarhq.com/pickups.html

*If you want to wind new single coils, you'll certainly find online the parts needed... but how do you plan to wind 8000 turns of super thin AWG42 wire with a right tension and without breaking it if it's your first attempt and/or without gear to do that? I've no doubt about your ability but it's difficult to wind a coil correctly from scratch...

I'd just use some Tinnerman nuts, personally. Or larger height setting screws. Or new pickups. There's dozens of vintage correct SC models on the market.

Now, do what you want and be happy... Good luck in your quest.

 

[jeremy]

a pic of the pup would help, but if its a classic design single coil, the bobbin flat work is structural and you cant easily replace it without ruining the coil. if you wanted to rewind, start fresh since the flat work hole is stripped. you would want to buy pole pieces that fit the bobbin flat work you buy. 0.187" diameter is common for strat pups. the height of the magnet can vary, i like 0.688" for all positions or even a bit taller for a bridge pup.

if you have wire and the ability to wind a pup, then a strat single coil is not a bad way to start. resistance is determined by the type of wire and number of turns (ie length of wire in the coil) what is there now is irrelevant to what you can make it.

 

[playas]

Thanks both for the responses. I don't have the pickups handy so I can't take pics, but the bobbins are definitely plastic and while I'll need to double check, they may well have a bar along the base as you mentioned freefrog.

The reason that I ask now without having them to hand is that I need to pick up some other mags so I thought of getting everything together.

I have never heard of a tinnerman nut before so I'll check into that, thanks.

The aim was never to get into pickup building and reading between the lines of what you've both written I guess that it would never be a case of rewinding the existing pups but winding entirely new ones from all new component parts so that answers my main question I reckon.

 

[freefrog]

Thanks both for the responses. I don't have the pickups handy so I can't take pics, but the bobbins are definitely plastic and while I'll need to double check, they may well have a bar along the base as you mentioned freefrog.

The reason that I ask now without having them to hand is that I need to pick up some other mags so I thought of getting everything together.

I have never heard of a tinnerman nut before so I'll check into that, thanks.

You're welcome. It's also possible to glue some bolts under the baseplates, for the record.

If your single coils have ceramic bars, it's potentially doable to unglue them and to extract the related steel slugs, then to order AlNiCo rods of the same diameter than these slugs and pull them in the bobbins . I've already done that.

It should make the sound brighter and more focused.

Doing your own pickups from part ordered on the Web is of course possible and would be very satisfying. Now the first attempts of winding can be discouraging (Tom Holmes stated somewhere that each day of work starts for him with 2 or 3 failed coils, albeit he has built thousands of pickups during decades).

Good luck anyway.

 

[playas]

You're welcome. It's also possible to glue some bolts under the baseplates, for the record.

If your single coils have ceramic bars, it's potentially doable to unglue them and to extract the related steel slugs, then to order AlNiCo rods of the same diameter than these slugs and pull them in the bobbins . I've already done that.

It should make the sound brighter and more focused.

Doing your own pickups from part ordered on the Web is of course possible and would be very satisfying. Now the first attempts of winding can be discouraging (Tom Holmes stated somewhere that each day of work starts for him with 2 or 3 failed coils, albeit he has built thousands of pickups during decades).

Good luck anyway.

If it´s possible to unglue the magnet and replace the steel slugs without dismantling the entire pickup, that would probably be the best solution, then a nut or something to allow for height adjustment of the pickup.

I take it that I would want to avoid removing the bobbin base at all costs as the wire would completely unravel?

 

[freefrog]

I take it that I would want to avoid removing the bobbin base at all costs as the wire would completely unravel?

With a potted coil on a fiber baseplate, it wouldn't necessarily unravel, but separating such parts is not easy, should be brutal if it happens and would at least probably break one or both of the start/finish wires... A pita to repair, if only it's doable.
Now, if your pickups are wound around plastic bobbins, their baseplates can't be pulled off anyway.

While I'm at it: gluing a fiber baseplate with proper screw holes under the existing pickup would be another solution.

 

[playas]

With a potted coil on a fiber baseplate, it wouldn't necessarily unravel, but separating such parts is not easy, should be brutal if it happens and would at least probably break one or both of the start/finish wires... A pita to repair, if only it's doable.
Now, if your pickups are wound around plastic bobbins, their baseplates can't be pulled off anyway.

While I'm at it: gluing a fiber baseplate with proper screw holes under the existing pickup would be another solution.

I did wonder if that might be a good solution alright

Thanks again.

 

[playas]

The pickups do have the two bar magnets along the sides of the base, to either side of the slugs.

They look like they've been potted with glue instead of wax.
I've removed a load of glue around one of the pickups and still going. Thus far there is no sign of any movement so it remains to be seen if I'll be able to get them to separate without damaging the coil, but I 'm taking it slowly so we'll see.

 

[playas]

Success!

I eventually managed to get through the glue and after removing the bar magnets, the slugs come out more or less easily.

Freefrog, I have one more question if you wouldn´t mind. The slugs are 5mm in diameter (0.196") and 22.8mm (0.870") long.

Should I try and replace them with polepieces of as close to that length as possible bearing in mind the pickup height is now 5mm (0.198") shorter without the bar magnets, or is there any advantage to longer or shorter polepieces soundwise?

I guess shorter poles would decrease the magnetic field and make lower the output a little?

 

[freefrog]

Success!

I eventually managed to get through the glue and after removing the bar magnets, the slugs come out more or less easily.

Freefrog, I have one more question if you wouldn´t mind. The slugs are 5mm in diameter (0.196") and 22.8mm (0.870") long.

Should I try and replace them with polepieces of as close to that length as possible bearing in mind the pickup height is now 5mm (0.198") shorter without the bar magnets, or is there any advantage to longer or shorter polepieces soundwise?

I guess shorter poles would decrease the magnetic field and make lower the output a little?

Hello,

Glad it worked.

I find difficult to answer about the required length, that said: sure, all other factors being equal, longer rod magnets should be stronger. But knowing how flux strength can empirically vary on rods on the same size / batch etc., I'd mainly try to find rod magnets of the proper diameter. Once that done, the result can always be tuned with added components (hex screws used as inductance boosters can be found under Fender single coils with plastic bobbins, for instance).

HTH.

 

[playas]

Hi guys,

The A3 pole pieces eventually arrived - believe it or not I´m still waiting for the flatwork - and I thought I´d give an update.

In the absence of the flatwork I tried the A3 poles with masking tape along the base of the pickup as a temporary workaround on the middle pickup with the neck still stock for comparison.
Masking tape so that 1) the poles don´t fall out and 2) the screws have something to grip instead of the flatwork with no thread.

Well, it was a bit of a disappointment. I couldn´t get poles that were as long as the slugs that were originally in the pickup so I ordered the longest ones they had...The pickup was really weak and lacking character compared to the neck even with a significant height difference in favour of the middle.

...When suddenly it hit me...I bet those poles aren´t even magnetized.

I did the screwdriver test and effectively, they´re not magnetized. I´m surprised I got anything out of them at all.

I don´t have any neo magnets, but I do have various A2, A5, and a single A8 magnet lying around.

Can I use a pair of A5 magnets to magnetize the poles? Can anyone give me clear instructions how I should go about it?

I guess I´d need to pick up a cheap compass as I don´t have one handy, although I believe the bars I took from some Duncan´s are marked North, so possibly I could use that for reference.

 

[jeremy]

ive never tried to charge magnets with anything but neo or an electromagnet, you can probably get some charge on there with a5 or a8, but i would guess it wouldnt be close to fully charged. due to the orientation of the magnetism on the bar, im not sure how itll work. also, it cant hurt anything so give it a whirl. there are youtube videos out there of how to do it, albeit i doubt any use an alnico bar, but the process is the same.

 

[playas]

Thanks Jeremy, will check that out.

 

[Artie]

If you search some hardware sites, they do sell those little inserts that some singles use. Can't remember what they're called. You'd have to drill the hole to the specified size, then squeeze them in.

 

[playas]

Never thought of something like that...I might look into that and cancel the flatwork if I find any.

Thanks.