When putting a new prop on a motor and it will not slide up the shaft, how does everyone get them on? Do you lightly drill out the center of the shaft opening, or just keep twisting it on until it gets there? Is there another trick I am missing?

If you drill the hub you need to be very sure that you drill it in the center. A drill can walk off center or not go through the hub square.

Most of us use a prop reamer. A few different manufactures make them. Great Planes for one. Use a reamer you will have better results.

DEG

Here is a link to a prop reamer. I use a drill.

http://www2.towerhobbies.com/cgi-bin...?&I=LXK248&P=0

Eric

Prop reamer, best way to go. They even make metric and SAE stepped reamers. Those are the best. I use an old Fox reamer I got back when Tyranosaurus was flying planes.

Mark Shuman

Use the reamer...less likely to make your prop unbalanced.

phread59, I got one of those Fox reamers, and for T-rex the only available model was the Pterodactyl, actually, that`s how the Taxidermist job was born. Just Kidding ! JT

Someone said it might make the prop unballanced. Does that mean the prop is ballanced from the factory? Or do I need to put it on my balance machine before using it?

Always balance/check every prop for balance. Most do not come balanced from the factory.

There is a new balancing device that has you shift the center of the hole in the prop to correct for imbalance. Its an interesting concept.

The idea behind this method of balancing is that many wood props have the holes drilled off center a bit, and that is the reason for the prop not balancing. Unfortunately.. the premise does not hold true for the composite propellers.

The way I ream out props is I have a step-tap "screwdriver" made by Klein tools. (carried in the electrical section at most Home Depot stores.) This tool is extremely accurate about keeping the hole centered. When I have tapped out to the same thread as the prop shaft (if its an SAE thread...) then I follow with a reamer to take out the threads. The step-tap cuts better than most prop reamers because it is made to cut metal... most prop reamers are made to cut wood. (and have a hard time with composite props) The prop reamers tend to get dull quickly cutting the Master Airscrew black props and the APC grey props.

Is OS engines SAE or metric? I will have to check out the step tap screw driver. One thing I have used was just a drill bit with no drill. I just press it down on the table back and forth, that way just taking off a little at a time as not to take too much off.

OS engines use metric screws to hold the thing together... and a SAE thread on the prop shaft.

1/4-28 for thier .40 class engines... almost always "SAE Fine" for whatever size they are using 1/4-28 is SAE Fine, 1/4-20 is SAE course.

Thanks