Hey everyone, first post here so forgive me if it's in the wrong place.  I'm a licensed private pilot, building a Cessna 172SP panel for use with X-Plane 11 (of course) and have a question about rotary encoders.  I'm building the panel with analog/steam gauges and plan to use them for things like the heading bug, altimeter setting, etc.  I'm new to building electronics but have been around electronics my whole life, so I get the idea of how they work.  My question is, how do you know which ones to buy?  I see 6mm, 12mm--what is that referring to?  My "panel" is 1/4 inch plywood so I need the threaded portion to be more than that, otherwise I'll have to rout out behind the panel enough to give the nut enough threads to hold onto on the front side.  Lastly, I'll be wiring them to a Bodnar BU0836X board.  Thanks for the help--love this forum!

Believe the 6mm is referring to the shaft mounting .. ie 1/4" shaft. usually the suppliers will list the encoder dimensions in a spec sheet. There are some very good FS hardware builder sites on the webnet with much good information. Iv'e build 6 or so panels using Bonars boards , encoder switches etc.

So is that 1/4" diameter, or length?  If length, I would assume that is the knob shaft only, not including the threaded portion?

http://www.ttelectronics.com/sites/default/files/download-files/Datasheet_RotaryEncoder_EN11Series.pdf

 

Check out the datasheet links for the encoders on the Leo Bodnar site, such as the one on this page.