A New Knob for my K2 (Stolen from a Yaesu FT900)

One day after a few hours of tuning my K2, I noticed that my 'knob turning thumb' was getting a bit tender due to the sharp edge of the stock K2 knob. I looked at my nearly idle Yaesu FT900AT and noticed that its knob had a nice smooth front edge and thought that I would see if it would fit on my K2. Several folks have reported happiness with the FT100 knob on their K2, but that is a bit on the small side for my taste.  

Armed with my trusty allen wrench, the knob was in my hands and no longer attached to its original host. It has a good heft to it – that meant enough weight to allow smooth knob spinning; the skirt of the knob would overlap the display bezel on the K2 by a bit, but not enough to cause a visibility problem.

The thickness of the bezel meant the knob would not rest against the K2 felt washer, and while it would spin with great ease, it would not stay in one place after tuning. This is the result of the Elecraft folks using a super smooth optical decoder in the K2. I needed something to shim out the felt washer to provide a bit of drag.



Looking about for something to use, I spied the anti-static foam that my K2 firmware chip was shipped in and thought it would be about the proper thickness – turns out that it did the job just fine.

I cut a piece of the foam to the approximate size and shape of the original felt washer. Both the felt washer and my new foam provided the right thickness to put drag on the knob.

I temporarily put the K2 knob on my FT900 so I could tune it - just in case, but I did phone Yaesu and ordered a new knob and ring

As of May 2004 the phone number for Yaesu parts is 1 (800) 283-7839, and the part numbers and prices were R3150470 ($9.88) for the knob and R3520371 ($0.53) for the ring.

Nov 2007 update - the FT-900 knob is no longer available, but the ring may be.  The FT-900 ring does fit over the stock K2 knob with a bit of a stretch to provide a cure for the sharp edge.  The FT-100 knob ring can also be stretched to fit, and the FT-847 knob ring similarly works.  Elecraft has the 'finger dimple' for those who like those and the combination can yield a knob that is quite usable for you.