There is a discussion that says the knob and pointer on a radionic instrument should be connected to the .25 shaft of the variable air capacitor or potentiometer. I have recently begun using this method to secure this connection. First off, I use knobs from Antique Electronic Supply @ http://www.tubesandmore.com.. The part number is P-K374. This is a large knob with space under the base; cost $1.40 each plus shipping.
I cut a 1 inch copper disc out of sheet copper and this disk fits under the base of the knob. Using a fine gauge drill three pairs of holes are drilled from the center hole out to the edge of disk. I loop copper wire through these holes to secure the needle I use as a pointer. I look for fine beading needIes around 2.5 inches long at Michael's or other craft shops. I wrap the needle with fine copper wire for .25 inch, then slide the needIe through the copper loops on the copper disk. I then pull the wire tight and solder the needle in place after assuring it protrudes the correct length. I then drill and tap a 4/40 thread hole into the knob base along side the .25 inch brass insert so that the tap will cut a partial thread into the outside surface of the brass insert. The disk is then secured to the base of the knob with a 4/40 X 3/8 inch machine screw. This provides a secure connection between the pointer and the shaft. Here are some pic's:
So - there you have it. This is a great pointer for fine tuning.
Happy instrument building to all who venture to do so. Doc
A forum for you to share and receive advice/guidance on your new radionics projects.
2 posts • Page 1 of 1
- Finished Knob and Pointer
- Finished knob and pointer.jpg (19.09 KiB) Viewed 2359 times
- Copper plate installed on base of knob and screwed along side brass insert
- Copper plate and pointer installed.jpg (18.29 KiB) Viewed 2359 times
- Copper plate drilled
- Copper Drilled Plate.jpg (10.4 KiB) Viewed 2359 times
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