Using round shafts on POTs instead of having a flat

I am currently looking for a POT for a project I am doing. I want the POT to be <=10kOhms and wire wound for reliability. Other than that (and some various size constraints) there is very little restricting me with my purchase.

However, when looking for wire wound pots I seem to be finding it very difficult to find pots with a flat on the shaft. I am intending on fitting a custom detent to it and attach a custom dial via a grub screw; grubs screws are very ineffective on a round shaft. It is possible for me to take some material off on the lathe, but for risk of damaging it on my limited budget I’d rather not.

Why is it so common to use round shafts when I assume the most common form of attachment is via set screws/grub screws?

Another quick question is, my project supervisor is suggesting I use a myRIO instead as they already have some available; so are they too dissimilar for arduinos and I assume the same breadboard is okay for using with the myRIO?


I would use a metal file and 'file' a flat on the shaft of the Potentiometer.

Yeah I was thinking that might be a better option. Cheers. Also I had meant mill before not a lathe. How important is the position of the flat?

Determines orientation of your 'custom dial'.

Yes, flatted shaft does not seem to be an option for wirewound pots.

Are the advantages of using wire wound in terms of lifespan that great over say conductive plastic?

The POT is to be used essentially as a potion sensor on a dial and from what I understand conductive plastic has a higher resolution making it a better option in some respect. Also conductive plastic seems to be cheaper. So would you say that using a conductive plastic POT instead for the advantage of resolution and the flatted shaft is a good idea?


Do it like this:

  • Position your dial to the exact position and tighten the setscrew so hard so it leaves an indetion in the axle
  • Take the dial off and use a small drill to deepen the indention made by the screw.

Thats a good idea, I had considered that, although drilling curved surfaces is not always a good idea. But as accuracy isn't THAT important, a pillar drill should do that okay.

I am now having doubts as to whether wire wound is the best option to go for. Would anyone reccommend a better POT; its to work as a position sensor on dials for a game essentially.

I had originally chosen wire wound as they are very durable.

Using a V-block makes it easy drilling a hole perpendicular to an axle

Is it difficult to take the input shaft out of the assembly normally?

Also any ideas on better POTS?

Actually, the pot you want is not "conductive plastic" but "moulded carbon". The quality ones have a little carbon block held by the wiper spring.