Identifying mystery knob - Page 1
Forum section: electronics / repair

author: Lomax
author_rank: Frequent Contributor
timestamp: November 19, 2017, 03:42:36 pm
content: Hi guys,I've spent hours trying to identify the collet knobs on a French MIG welder I'm restoring (a GYS Pearl). Farnell, RS, Mouser, Rapid, TME, Google Images... no stone left unturned but I cannot find a match! The MIG has two rotary encoders on the front panel, and one of them has lost its "knob cap" which annoys me greatly. Ideally I would want to replace with one identical to the other, second best replace both caps, third option replace both knobs entirely. Posting here in the hope that maybe someone will see this and know immediately what make they are. 23mm dia at base, 21mm at top, 16mm tall (excluding cap), shaft dia 6.35 or 6.4mm. Anyone recognise these?

author: amyk
author_rank: Super Contributor
timestamp: November 19, 2017, 04:27:46 pm
content: Google: collet knob 21mm 6.4mmhttp://my.rs-online.com/web/p/potentiometer-knobs/4638463/Here is their whole catalog:http://www.sifam.co.uk/Downloads/Content/sifam-controls-catalogue-v2-web.pdf

author: kayvee
author_rank: Regular Contributor
timestamp: November 19, 2017, 04:28:14 pm
content: Elma perhaps?Reminds me of the ones we used to use in the '80's

author: cvanc
author_rank: Frequent Contributor
timestamp: November 19, 2017, 06:45:47 pm
content: Way back when I think Alco (known more for switches than knobs, I think?) made stuff like this. Not sure if they're even still around... in any case good luck finding something.

author: stmdude
author_rank: Frequent Contributor
timestamp: November 19, 2017, 10:20:44 pm
content: Know anyone with a 3D printer?This should be a 5 minute CAD-job for them, and about 20 minutes of printing.Or, anyone with a lathe. Should be a quick job for them with a delrin rod.

author: Lomax
author_rank: Frequent Contributor
timestamp: November 20, 2017, 11:24:10 am
content: Thanks everyone! I think the knob suggested by amyk gets pretty close, appearance wise, so I might go with that and replace both knobs. Shame that it is so difficult to locate caps to fit a given knob - it's a common problem that these go missing...Edit:Ah, but there's a problem with those RS Pro knobs; they only come with black capsTo keep the original appearance I need (pale-ish) yellow caps! Back to square one.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: November 20, 2017, 01:54:56 pm
content: Why replace the knobs ? Just get new knob caps. (if one is so bothered about knob caps that is)

author: Lomax
author_rank: Frequent Contributor
timestamp: November 20, 2017, 09:41:59 pm
content: Quote from: Bashstreet on November 20, 2017, 01:54:56 pmI would prefer this, as I said in my original post, but the problem is locating caps which fit.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: November 21, 2017, 03:39:37 am
content: Well i would not personally bother but if you really want restore the equipment to factory default and are ready to spend quite bit of time and energy you could ether order similar cap (long as it is not too small) Or use material at home and make facsimile using the another cover.If you get similar knob cover you can then modify it to make exact fit (size profile and appearance)1. If the knob is too large you can remove material carefully retaining symmetry and finish with gradually finer sandpaper till you get to 500 grit.2. If the color is not same you can get (depending of the plastic used) Acrylic model paint.3. Order extra covers to practice with.4. If the caps do not retain you can use suitable flexible clue that is easy to remove and leaves no residue (for future repairs removal of knobs etc.) (or use mechanical fastening of your choice)Good luck