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newbie question re: potentiometers


RTurner
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Does anyone know of any practical reason why one should use potentiometers with metal shafts versus plastic?  Are they more prone to breaking?  Bending? 

The reason I ask is: I like the "feel" of Bourns potentiometers, however; the only ones that seem to be reasonably priced have plastic shafts.  Even the approx. $3 that mouser wants per potentiometer is a bit steep for me, but, $3 is closer to my price range than the  5+ dollars the others are going for...

Thanks,

Robin

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Nohohooooormallyyyy (***) metal shaft pots have higher power ratings and are used for that stuff (e.g. in row with relais, direct control of motors and other higher power (>0,5W) stuff). So in MB´s there´s aaabsolutely no need for metal shafts.

Greetz

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I am actually using plastic shaft pots from Bournes that I found for next to nothing (.75 a piece!). There are potential issues if you are really tough on equipment, but if not then there's no big difference. The forces applied to the shaft are primarily rotational, and so a composite shaft is just fine - particularly in the larger sizes. But I tested my pot choice through 1 straight hour of back and forth twisting - no degredation noted, and that is on a 1/8" shaft!

EDIT: No Masturbation jokes please. :P

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Alright, the good news: at a local computer/electronics store I found a stash of bourns pots that are pretty much everything I need... 10k, 5/8" diameter base, great <ahem> rotational action on the shaft, they're even of the conductive plastic type.  I was able to buy a box of 26 for $40!  (eat it, mouser)

The trade off:  the shaft is metal, but it's 1/8th inch in diameter........  were aluminum knobs just never made for 1/8th inch shafts???  Oh well, thanks for the swift replies guys.

Robin

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the shaft is metal, but it's 1/8th inch in diameter........  were aluminum knobs just never made for 1/8th inch shafts???

Check my post in Parts Archive titled "God I love Knobs"!, where you will find a company that makes very nice aluminim knobs for 1/8" shafts.

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