"Thin walled" socket for crank nut and fan?
 

Hi ya'll, I have a little project that involves the fan from an X-Cell Fury and a prop adapter. The prop adapter goes from a 6mm electric motor shaft to a (fairly standard, I thought) 5/16-24 shaft for mounting a prop....or, in this case, a 700-size heli fan.

My problem is that I can't get a socket down into the fan to torque down the crankshaft nut. I spent the afternoon hitting local hardware, auto parts, and building supply stores looking for a thin-walled socket, OR a nut with 5/16-24 threads and a smaller outer diameter. The nut is 1/2". If it were 7/16" or 12mm, I'd be ok. It seems pretty much every 5/16-24 nut on the planet is 1/2". There's probably some perfectly logical metallurgic/strength reason for this, but that's beside the point....

Just precisely how do they expect you to torque this thing down??? The only "thin walled" sockets I find are specifically for impact drivers....which is immaterial, except the only reason they are "thin" is that they are only thinner than standard IMPACT sockets, which are quite thick. The 1/2" socket in the thin-walled set I found looks to be the same outer diameter as the other 1/2" sockets I've tried.

The inner diameter of the center area in the fan is right at 17mm.

Matt
https://cimg6.ibsrv.net/gimg/www.rcu...5cda418dcb.jpg

It's time for "roll-your-own". Find a local maker place. That's where the guys with 3D printers and CNC machines gather. They usually have a guest night during the week. Take a socket with you and see if you can get one of them to put it on a lathe an trim the outside down a bit. You probably only need to do about a 1/4 inch of the tip.

Most Helicopter engines have a 1/4" threaded shaft. The area on the crank where the tapered collet goes on is usually 8mm (very close to 5/16"). I had run into your same problem a few times back in the day, I just took one of my sockets and modifies it with a belt sander. The second issue you may run into is that it looks like the shaft and nut are sticking up above the the hub a little. This will keep the clutch from sitting where it needs to be.

Snap On is where I got mine