Spring identification

[Floyd1807]

Hello All,
I am trying to identify a spring. The best description of it is that it looks similar to a spring pin but performs the opposite function. Typically you would insert a shaft at either end of the spring and spring tension hold the shafts in place. The application, as I recall, was to extend the shaft of a potentiometer where the rotational forces required were minimal. I am aware of shaft coupling devices that would do the job but these are not suited to my application. Does such a device still exist and if so what is it called?

 

[desertfox]

Hi

Do you mean a circlip?

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[Floyd1807]

Thanks for responding.
If you could take thin slice off the end of this thing you would have something approaching a circlip.
However, a circlip requires a groove to sit in. It really does look most like a spring pin.

 

[desertfox]

Hi again
Can you post a sketch of this thing? Sounds like it’s a spiral pin

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[3DDave]

It seems like it's a hollow pin, rolled like a spiral pin, that grips a shaft. Given that most pots are available with sufficiently long shafts and that most knobs are designed for those shafts, it's likely that any of them in the wild are custom made.

Here are some other ideas:

https://www.eevblog.com/forum/projects/how-to-extend-pot-shaft/

Or just a piece of brass tubing with a little crimp to the end to ensure a grip on the pot shaft. What happens on the other end depends on the knob, but either crushing that end or using a smaller telescope fit tube to match the pot shaft diameter into the knob with a touch of solder or a piece of brass rod (also soldered.)

 

[Floyd1807]

It is true that many pots have quite long shafts however this is not the case with my application.
I am aware of quite a few options for shaft coupling however this is the one I would like to pursue first as it is by far the best for my application.
The only difference that I can see between a spring pin and a spiral pin is the number of turns within the spiral. Where the spring pin has less than one turn and the spiral pin has greater than one turn.
In any case these are designed to be inserted into holes rather than to have a shaft inserted into them. The spring tension of these devices (pins) would probably be an order of magnitude greater than the device I am envisioning.
I have gone down quite a few paths to try and identify this device. The fact that I am having so much trouble probably means that young 3DDave is correct and the one I have seen could be a custom job.
Fear not I do have a plan B.

 

[3DDave]

Young. Uh, sure.