3/7/21

Hi David,

Here’s a set of different fingerpieces for the cootie side. One side is offset more from the centerline. When you mount it so the offset side is towards the center of the key, it will decrease the paddle distance by 2,4,6 or 8mm (6.35mm = 1/4 inch). They aren’t marked, but your calipers will show which is which.

I went back through my notes. My LH version measures 34mm between the trunnions. I reduce it to around 26 with fingerpieces. When I sent you photos, your reaction and the reaction of the Morse Code group was the spacing looked way to wide. And Lery said it must be 32mm. It’s easy to make the paddle spacing narrower, but difficult to make it wider. So I redesigned the one for you at the widest likely to be required figuring it can always be made narrower with the fingerpieces. I didn’t want to ship you something that would be too difficult to modify long distance.

Bottom line is I could easily print a smaller bridge/mainframe for you. Mine is the narrow one with 34mm wide trunnions. Yours is the wider one with 40.35mm wide trunnions. That is roughly the 25% reduction in size you calculated. However, that would mean you would have to disassemble the key and install everything with the new bridge. If you are interested in doing that, let me know. It’s not overly difficult, but it’s a little fussy. You are the best judge of your current capabilities.

I would suggest fixing the paddle distance with the enclosed fingerpieces and trying to get up to speed that way. If you then want to swap out the bridge, let me know and I’ll print one. ’

BTW, let me reiterate, this is not a commercial venture for me. I have absolutely no interest in selling this or any 3D printed bug—too much like having a job (hi). My interest is strictly in exploring mechanical design for 3D printing using a fun subject: semi-automatic keys. If anyone has any interest in making one, I provide the files free. They just have to ask.

Eric KE6US

N.B.:  Eric hasn’t been heard from since April 2021, I think he is either in hospital, or he has died.  He doesn’t answer his email from myself or others.
/DR N1EA