I have an old track ball that has a 1.75" ball in a 5" x 5.5" base that I think is what you are trying to build. If it is not about saving money, Kensington makes two models that should do the trick. Newegg has them. Models 64325 and K7232US
David K0LUM On Jan 17, 2013, at 6:07 AM, Bill Clarke wrote: > I have found a cheap and effective answer to the problem that requires no > changes to the K3 and no soft in addition to the free version of HRD that I > am using. > > I took a mouse apart and removed the opto-wheel's detent spring. The wheel > now spins freely. Although the diameter is small compared to a "real" tuning > knob - I can control the tuning speed from HRD. Works for me. > > At some point in the future, I may take another mouse apart and remove the > optical encoder and build a new frame and enclosure for it - then add a > "real" sized tuning knob to same. However, having the smooth tuning > capability along with right and left clicks of the mouse is really convenient. > > Bill W2BLC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html