There's one fancier replacement, a vernier scale that allows reading the dial to a tenth of a division. Either one is a nice thing to have when the urge to build some interesting device happens to strike.
Friday, August 23, 2013
GENERAL RADIO KNOB AND INDEX
It showed up ay a popular auction site: a genuine GR calibrated knob:
In the original box (love those fonts!):
With an "index:"
Actually, three of them, and that's the part you never see. Sure, it's just (just?) a line scribed on a piece of metal, the same nickel-plated brass as the calibrated skirt, but it's mounted on a little leaf spring and shaped to ride right on the edge of the calibrations. It beats the usual crude expedients by a long ways.
There's one fancier replacement, a vernier scale that allows reading the dial to a tenth of a division. Either one is a nice thing to have when the urge to build some interesting device happens to strike.
There's one fancier replacement, a vernier scale that allows reading the dial to a tenth of a division. Either one is a nice thing to have when the urge to build some interesting device happens to strike.
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Is this a vernier drive one, or "just" a knob that fits on a shaft?
ReplyDelete"Just" a knob -- in size and appearance, it's a near match for the Crowe reduction drive unit I bought at the Indy hamfest. GR made a little pinch-disc edge drive for these knobs, which gave a ~5:1 reduction. (National did the same for the similar-looking type O knob with calibrated skirt. Theirs was the "O dial drive," part number ODD!)
ReplyDeletePretty neat. It looks new.
ReplyDeleteI had a few of these and a few verniers from helping to clean out an SK's shack. I didn't have a use for them at the time, so I sold them on eBay.
Still kicking myself over that.....