I'm wondering if there is an easy way to mount a nylon prop on a un-knurled prop hub face.
An example of a smooth (un-knurled) hub of an SPE 26cc engine is shown. The back of the nylon
Master Airscrew (and many other nylon props) prop hub has molded in spaces that do not allow a drill
to track straight when using the prop washer as a drill guide. The drill is trying cut into half of the nylon.
The drill never goes thru straight. This, of course does not happen with a wooden prop.

When trying to mount without drilled bolt holes thru the prop hub, the prop will spin loose. Short of milling the little bolt holes
out with an end mill, is there another way to drill this out? Or is there something that can be used as a locking
washer between the back of the prop and the aluminum prop hub?

Looking forward to your suggestions!

A disk made of sand paper will help. Make two disks and glue them together back to back

Yep, that works well. And use a prop hole reamer when enlarging the center hole in any type of prop.

AV8TOR

Just tried the sand paper suggestion. Works great!
Thank you!

Glad it worked for you. Harbor Freight sells a set of hole punches that work great for things like this, and/or making gaskets.

AV8TOR

Ck out the Master Air Screw web site. The Classic series props hubs in the larger sizes are now made for four or six bolt mounting hole drilling. They show pic. of the hubs in the Classic prop section of their website. I have two 18-10 Classic I have not drilled out yet.