Dual axis potentiometers? - Page 1
Forum section: electronics / projects

author: Martinn
author_rank: Frequent Contributor
timestamp: August 21, 2024, 06:26:32 pm
content: Hello all,for a milling machine power feed (personal project, qty = 1) I'd like to have potentiometers that have a coarse/fine adjustment in two coaxial knobs. Like many old scopes had on the X and Y scale settings, outer one for the range and an inner one for dual timebase or fine adjust.Now this is purely cosmetic and just for fun (I can simply place two potentiometers side by side), but I wondered if you could still buy those.Sifting through Digkey I found thishttps://www.digikey.ch/en/products/detail/tt-electronics-bi/P082D-27CBR10K/2620655one by sheer luck - there is no filter one could apply and I had to go through the images. This is perfect, they have 2000 in stock and it's not even expensive. But still, only one out of 635178 potentiometer models on Digikey? Would anyone know where to look?Next will be finding knobs for that (same problem), although as backup I could make them on the lathe (nice knurling exercise).Thanks! Martin

author: themadhippy
author_rank: Super Contributor
timestamp: August 21, 2024, 06:55:40 pm
content: Quotecommonly known as a concentric pot ,for knobs maybe try your local guitar store

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 21, 2024, 07:40:22 pm
content: Another term that has been used for these is ganged potentiometers. Haven't tried this on the usual distributor sites so don't know if it will help.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 21, 2024, 07:54:38 pm
content: Sorry, upon checking found that ganged is reserved for non-independent resistor elements. But concentric does work. Looking, it seems that the guitar industry is solely responsible for keeping this option alive.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: August 22, 2024, 05:07:38 am
content: Alps call these dual shaft modelshttps://tech.alpsalpine.com/e/products/category/potentiometers/sub/01/series/rk097/

author: Martinn
author_rank: Frequent Contributor
timestamp: August 22, 2024, 05:39:31 pm
content: Quote from: PCB.Wiz on August 22, 2024, 05:07:38 amSo this makes two types... but at least they are available.It seems guitars are the driving force, lots of knobs therehttps://www.thomannmusic.ch/potiknoepfe.html?feature-1757%5B%5D=Dome%2C%20Tandem&feature-1757%5B%5D=Fender%20Potiknopf%20Lower&feature-1757%5B%5D=Fender%20Potiknopf%20Upper&feature-1757%5B%5D=Tandem&feature-1757%5B%5D=Stacked&gk=GIETPK&sp=solr&category%5B%5D=GIETPK&cme=true&filter=truealso a few potshttps://www.thomannmusic.ch/potentiometer.html?feature-1761%5B%5D=Stacked&feature-1761%5B%5D=Tandem&gk=GIETPO&sp=solr&category%5B%5D=GIETPO&cme=true&filter=true"stacked" or "concentric" is the naming here.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: August 22, 2024, 06:37:55 pm
content: didnt the old ww2 style radio's have these geared "knobs" with one output shaft that was then connected to the POT ?

author: tooki
author_rank: Super Contributor
timestamp: August 23, 2024, 07:57:18 pm
content: I think it’s somewhat important to point out that the definition of “coaxial” issharing one axis, and that a “dual axis potentiometer” would actually be the exact opposite of what OP is actually looking for!

author: Martinn
author_rank: Frequent Contributor
timestamp: August 25, 2024, 10:20:43 am
content: Quote from: tooki on August 23, 2024, 07:57:18 pmNaming is completely random. Double shaft, coaxial, stacked, dual axis... Might be any of those. Sometimes even the pictures are wrong, so you have to find/read the datasheet and compare the descriptions. Also neither Digikey nor Mouser (nor any other shop) provides a working filter for what I am looking for.With Aliexpress, "double shaft" help:https://www.aliexpress.com/w/wholesale-double-shaft-potentiometer.html

author: tooki
author_rank: Super Contributor
timestamp: August 25, 2024, 11:33:12 am
content: Quote from: Martinn on August 25, 2024, 10:20:43 amIt certainly is not random. Inconsistent perhaps, but not random.Dual-shaft, double-shaft, concentric, coaxial, etc are perfectly correct (though in some cases unusual), because the two (or more) shafts share the sameaxis.But dual-axis is wrong for a potentiometer with concentric shafts. Not a little wrong, very wrong. Dual-axis means having two axes, like X and Y on a milling machine bed. They mean twodifferentplanes of movement.And indeed, if you search for “dual axis potentiometer”, what comes up is potentiometer-based joysticks, which do indeed detect X and Y position.Just to be explicit:axisis not a synonym forshaftoraxle. Anaxisis animaginaryline that something moves along or around. Anaxleorshaftis aphysicalrod or similar item that rotates.Searching for “coaxial potentiometer” doesn’t find much at all. It’s not really a term that’s used.“Concentric” is the key word you really want, because that is the word that unambiguously describes the shaft arrangement you want.“Stacked” is not reliable, because a stacked potentiometer can also be non-concentric, sharing just one shaft. (Like a stereo pot, for example.)

author: tooki
author_rank: Super Contributor
timestamp: August 25, 2024, 11:59:47 am
content: Quote from: Martinn on August 25, 2024, 10:20:43 amDigikey actually does, indirectly: the shaft diameter. If you look at the example you found by luck, you will see that under Actuator Diameter, it liststwodiameters: “0.138" (3.50mm), 0.197" (5.00mm)”If you look at the parametric search, you’ll see that there are a number of two-diameter entries in the list of actuator diameters.Unfortunately, the one you already found is the only one they stock. The other 44 “active” parts you’d have to order an entire box of.