Andy, I had luck making a plastic knob from scratch a while back. I needed a knob for a little Dremel jig I built for creating Manhattan style PCB pads. I think my knob was about 2" in diamater.
Basic supplies: - Polyester plastic casting resin - Hardener (for resin) - Mold The casting resin and hardener can be had at local crafts stores around here. I presume it wouldn't be hard to find across the pond either. For molds, I have had good luck with Polyethylene (HDPE / LDPE) and Polypropylene (PP), without using a mold release agent. That being said, I also cut the mold off, so they end up being one time use for me. Mold release (available according to the resin manufacturer), or a better shaped mold (nice draft angles) might let you reuse molds. For my knob, I used an empty plastic single serving fruit cup. I wanted a threaded rod coming out of the back of it, so after pouring the resin in the mold, I gently set a bolt into the puddle of liquid plastic. 24 hours later, and the bolt is a permanent part of the knob. It's not exactly perpendicular to the knob face, but only a few degrees off, and unimportant for what I needed. A little work and you could find a way to embed one and make it square. Once my knob was done, I faced the back a little bit by chucking the bolt end into my little drill press. A little work holding a file against the back edge, and I shaped it to my liking (flattened it out a bit, and smoothed over the "corner"). Link to the casting resin manufacturer's site (surely there are others, but this is the brand I used): <http://eti-usa.com/consum/index.html> scroll down a little bit Picture of the style of fruit cups I used for a mold: <http://tbn0.google.com/images?q=tbn:lBqSO-1t6kwCAM:http://www.packworld.com/thumbsLarge/issues/03.03/images/Features/DelMonte.jpg> If you go this route, and have more questions, feel free to send me some mail directly. I skim this list in digest, so I might miss a reply sent there. -detrick KI4STU On 7/31/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > Date: Tue, 31 Jul 2007 04:42:32 +0100 > From: "Andy - GM0NWI" <[EMAIL PROTECTED]> > Subject: [Elecraft] Project Knobs > To: "'Elecraft Discussion List'" <elecraft@mailman.qth.net>, "'Flying > Pigs'" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>, > <[EMAIL PROTECTED]> > > Hello to everyone in the group from "Bonnie Scotland".. > > I am currently tryin' to source some 2 inch - 2 1/4 inch diameter knobs for > a project that will be gettin' undertaken in > The near future.. > > I am in need of 3 sets of 3 (9 knobs in total) "I think".. although this may > not be case as I progress > But better I think to "plan ahead".. > > Can anyone on the list give any details of a supplier, ..or possibly some > ideas from a what type of older > Radio's in the past might have had this sort of diameter of knobs > included..? > > Think "VFO -Tuning Dial" sort of diameter.. and you'de near a ball-part > figure/size.. > > Has anyone in the past home-brewed this size and diameter of knob for a past > project..? If so, care to share how you > Did it..? > > I've looked around the internet are lots of places, and there just does'nt > seem to be anyone out there who stocks > This sort of thing, both here in the UK and the US and further afield.. > > Really would appreciate help or ideas on this one folks.. > > TIA.. > > 72's 73's [EMAIL PROTECTED] > > Andy > GM0NWI > > Elecraft K2 "Fully Loaded" QRP S/n 01432 > Elecraft K2 "Fully Loaded" QRO S/n 05469 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
