Measuring Tension On Wound Pickup

[Beef Coon]

Hi,

Anyone have a method of measuring tension on a dead pickup as you unwind it, or another way?

Searched and couldn't find any information on this.

[big_teee]

Hi,

Anyone have a method of measuring tension on a dead pickup as you unwind it, or another way?

Searched and couldn't find any information on this.

Just my own thought and take on it?
After the pickup sets for a while, and the copper wire sets, especially if potted?
The Pickup is relaxed, and no tension is present, and no tension to measure?
Guys correct me if I'm wrong?

[copperheadroads]

Hi,

Anyone have a method of measuring tension on a dead pickup as you unwind it, or another way?

Searched and couldn't find any information on this.

A Pickup that is not potted is pretty easy to tell ,But if it's potted I think it's hard to tell ..You will have to know how wire builds under different tensions .

[Lyrebird Steve]

Anyone have a method of measuring tension on a dead pickup as you unwind it, or another way

I'm assuming you don't have a way of approximating turn count (reference pickup DCR / wire type)

... if you can approximate the # of layers by unwinding a couple and getting a rough Turns per Layer count.

Feed this info into the Coil Estimator and work out Fill efficiency.

Alternatively ... you could check the thickness of the coil using calipers along the coil. High Tension= small variation ... Low Tension = big variation (this is what I see in my coils at least

[Beef Coon]

Thanks for the responses guys.

Tee, that's a good point - tension could change over a bit of time.

... those appear to be ways to get a "rough" idea of tension, versus a specific measurement no?

[big_teee]

Thanks for the responses guys.

Tee, that's a good point - tension could change over a bit of time.

... those appear to be ways to get a "rough" idea of tension, versus a specific measurement no?

If the bobbins are bowed and flared a lot, they were probably wound real tight.

[rhgwynn]

Measure resistance.

Unwind with device that measures wire length.

Compare numbers to what they "should be".

Apply logic and make an educated guess.

Higher resistance than "should be" means tight winding.

Don't forget to compensate for temperature.

You could also use a micrometer to measure wire thickness around the turns.
Sometimes tension can stretch 42 to 43 spec or smaller around the turns,
which would get you to your DCR target faster than expected.

-Rob

[copperheadroads]

Measure resistance.

Unwind with device that measures wire length.

Compare numbers to what they "should be".
Goodluck with that
Apply logic and make an educated guess.

Higher resistance than "should be" means tight winding.

Don't forget to compensate for temperature.

You could also use a micrometer to measure wire thickness around the turns.
Sometimes tension can stretch 42 to 43 spec or smaller around the turns,
which would get you to your DCR target faster than expected.

-Rob

[ATTACH=CONFIG]23400[/ATTACH]

Goodluck with trying to unwind a potted pickup

[rhgwynn]

Goodluck with trying to unwind a potted pickup

Yeah, no doubt. It's not easy; and quite a mess, with all the wax and what not.

Might be easier if you have constant source of heat though...? *Shrug*

-Rob

[copperheadroads]

Yeah, no doubt. It's not easy; and quite a mess, with all the wax and what not.

Might be easier if you have constant source of heat though...? *Shrug*

-Rob

I can usually tell roughly how much tension is needed buy listening for certain aspects of the tone when listening to it played in a guitar or a clip played .
But this don't help the OP

[big_teee]

Measure resistance.

Unwind with device that measures wire length.

Compare numbers to what they "should be".

Apply logic and make an educated guess.

Higher resistance than "should be" means tight winding.

Don't forget to compensate for temperature.

You could also use a micrometer to measure wire thickness around the turns.
Sometimes tension can stretch 42 to 43 spec or smaller around the turns,
which would get you to your DCR target faster than expected.

-Rob

If you can read DCR, you probably wouldn't be rewinding it.
I never rewound a vintage working pickup.
T

[Joe Gwinn]

Hi,

Anyone have a method of measuring tension on a dead pickup as you unwind it, or another way?

Searched and couldn't find any information on this.

It's pretty difficult to measure after the fact.

What do you hope to use the information for? Perhaps there is a better approach.

[Beef Coon]

That's what I figured. It's for the purpose of "duplicating," or matching, the coil as closely as possible. Other details can be measured and matched more or less - OD of wire, ohms per foot, TPL, total turns etc. Matching the tension would be an important factor as well I'd think, no? I haven't been able to find any discussion on it - including the old board, so maybe I'm wrong or it's not possible. I also think it would be useful to know how far from the bobbin the wire is fed onto it, but I don't see how that's possible just from the examination of a coil either.

[Joe Gwinn]

That's what I figured. It's for the purpose of "duplicating," or matching, the coil as closely as possible. Other details can be measured and matched more or less - OD of wire, ohms per foot, TPL, total turns etc. Matching the tension would be an important factor as well I'd think, no? I haven't been able to find any discussion on it - including the old board, so maybe I'm wrong or it's not possible. I also think it would be useful to know how far from the bobbin the wire is fed onto it, but I don't see how that's possible just from the examination of a coil either.

There are many threads on this and related issues. In my opinion:

The most important things to know are the turns count (not the DC resistance), the wire size (AWG), the wire insulation thickness (single or double build), and the physical dimensions of the coil (winding shape seems to matter).

The DC resistance varies with all manner of irrelevant details, so don't take it too seriously.

Insulation type does not matter, but thickness does matter.

Wax or no wax matters only for the level of microphonics - some people like a little microphonic sensitivity, but too much yields a squeal. Likewise epoxy potting et al.

Wax or epoxy saturation of the winding prevents moisture accumulation, the prevention of which was Leo's original reason for wax impregnation of pickup coils.

[Beef Coon]

Thanks Joe for taking the time to write, that's a great summation.

Tension matters and I have not found any discussion anywhere as regards to measuring the tension of a wound coil, unless my search skills are really that bad... but maybe they are?