What is this tool?

[BJuby]

A/B/C prop shaft (quickie) perfectly fits on the center rod. Is it a prop sharpener? Or maybe some pitch calculator? I have never seen something like this before. Thanks

http://i1088.photobucket.com/albums/i326/Astrolia44/C3594A4F-BFA0-40F1-A602-FECA6F83B23F-48385-00000ED5ECC6CC9E_zps4b372533.jpg

[Bill Van Steenwyk]

A/B/C prop shaft (quickie) perfectly fits on the center rod. Is it a prop sharpener? Or maybe some pitch calculator? I have never seen something like this before. Thanks

http://i1088.photobucket.com/albums/i326/Astrolia44/C3594A4F-BFA0-40F1-A602-FECA6F83B23F-48385-00000ED5ECC6CC9E_zps4b372533.jpg



I can't say I have ever seen anything like it either, but if I had to take a wild guess, and you mean by your statement that a prop with A/B/C prop shaft size HOLE will fit on the center shaft, then possibly it is something made to check blade concentricy (sp) on propellers by placing the prop on the center shaft, adjusting the pieces that look to be adjustable inward and outward on three sides of the round disk, so as to contact the bare edge of one blade of a three blade prop.

After the adjustment is made, and each adjustable piece is contacting a blade edge, then rotate the prop and see if each blade is concentric to the others in a 360 degree circle.

I may be full of it, and probably am, but I can't see what other use you would make of it, and also that is the first thing that comes to mind.

[BJuby]

Yeah, the center rod fits the prop shaft hole. Yes, those three rectangular objects do pivot inward. Did you see the markings on the surface, they look like what timing marks look like on a flywheel. And they are perfectly positioned for the three blade prop....

[Bill Van Steenwyk]

I thought that maybe the markings on the surface would possibly be 120 degrees apart, but difficult to tell the way the light reflects off the surface of the plate in the photo.

If they match a three blade prop spacing, then perhaps you do not have all of the tool or whatever you want to call it.

Reason I say that is I used to have a pitch gauge that allowed you to check and see if the pitch was exact on all three blades of a prop, or how ever many blades it happened to have by taking a reading of the pitch from one blade, leaving that indicator in the same location, then rotating the prop to the next blade reading with the indicator left in the exact same location. You could then tell if the blades were exactly the same pitch on all. I do not see anything that resembles "the rest" of the device, if there is more left, to do that type of measure.

Hopefully Ron Hill will see this thread and let you know what he thinks. If in some way it measures a prop, I'm sure he would recognize it.