Daily Archives: February 1, 2018

Goodies

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[Today’s run: 3.5 miles]

I’ve taken apart a few of my new acquisitions and I have some interesting pieces.

Most knobs that I run into use a 1/4 inch shaft.  Then they usually have one or two set screws, either allen head or flat-head set screws.  I have added to my stock more of that type.   These other knobs instead have a plastic cover to pry off.  Under that is a nut which operates a wedging “cap”. The knob itself is lined with a brass tubing.    The cap goes on the shaft and squeezes from all sides as it is drawn up by the nut.   Pretty fancy stuff.

And I’ve run into a handful of these peculiar vernier reduction drive mechanisms. Most that I run into have a 6:1 reduction. These guys seem to have something closer to 25:1. The knob will turn 270+ degrees (not quite a full circle). But the potentiometer on the other side of the reduction drive only turns a little bit. The example I’m showing in this little video is a 20,000 Ohm potentiometer. The portion covered by the motion of the knob is only 700 Ohms. I’m not sure why they built it this way instead of using a 1,000 potentiometer and a directly-connected knob.

 

 

Feb 1, 2018
« More stuff to take apart | GPSDO – finally, maybe, finally »
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