[ARC5] [Milsurplus] ARC-5 Tuning Knob Needed

[Kenneth G. Gordon]

On 4 Dec 2017 at 21:42, Richard Solomon wrote:

> I picked up a BC-453 to use on 472 KHz. I need a splined knob to tune
> it. 
> 
> There are a number of plastic splined knobs on e-Pay, but not sure what
> fits. 
> 
> Anyone got a knob they will part with ? 
> 
> Tnx es HH, Dick, W1KSZ

Hello, Dick. There are at least three versions of a knob the military used with these 
receivers. One, which we call "the wee knob", originally was included fastened under the lid 
of some of the later model AN/ARC-5 receivers. I have not seen any of those show up on 
eBay, but I'll bet they have. The second model, with a small crank on it, was used in the 
repair shops. Those normally sell on eBay for around $30 each. A third, much more rare 
knob was similar to the type 2 above, but had a scale on it. Those I have seen on eBay sold 
for $50 and more.

Personally, I have never liked any of those OEM knobs as they exhibit a terrible amount of 
back-lash, whereas the tuning mechanism in the receiver itself is completely back-lash free. 
They fit very sloppily on the spline and make zero-beating very difficult.

So, I make my own by cutting off a short section of 1/4" diameter hard-brass tubing about 1" 
long or so, cut two slots about 3/8" long parallel to the long axis of the tubing on one end, 
then I drive that "split" end over the splined shaft, install a good knob on the other end (the 
larger the knob the better), center it up, and, bang!, instant back-lash-free tuning knob.

If you really want to, you can use a bunch of super-glue to make it so it never comes off, but 
I have never needed to do that.

Ken W7EKB

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