Now have 12 new props, all 16 & 18" with factory bores from .25" to .310" front end holes. The aft ends on come are .362" tapering to .30" at front.
The specs available on these props all mentioned that they could be reamed out (some stated to .375". I am now the owner of a 'name brand' prop reamer.
All of the props have a hub thickness greater than the length of the reamer.
What is the proper method of using this 'tool'? A) just keep going till the right tip diameter comes out the front of prop? or B) remove and insert from opposite side?

Are reamers meant to serve a regular purpose on your props or is it like an EMERGENCY use when you break one at the field? I ran dial calipers over this new unit with the following results: 3/16" .1875 tool cut edges .195 +.0075"; 1/4" .25 tool cut edges .259 +.009"; 5/16" .3125 tool cut edges .316" +.0035; 3/8 .375" tool cut edges .364 -.0011



What type of fit are we looking for? a) a little play, b) snug slip fit, or c) lets apply a little more pressure and push that hummer onto the shaft?

Are the prop shafts on production RC motors normally a true dimension. like 5/16" shaft equalling .3125"? I'm looking at having adapter shafts made locally and can specify dimensions.

After inspecting the props and reading the install warnings on having proper bearing surfaces to assure safe operation, I was glad I opted for the LARGE 3" GP spinners. Wrong!! The raised 'knerled- grip' area is 1.36" diameter which gives it only a limited contact surface, less than what the prop manuf. say they want for safety. 16" and larger dimeter props won't even fit inside much less fit thru the side openings.

Support you LHS. Tower has a nice site and my experience with them was good. I would have preferred to have had the 'hands-on, let's see how this is going to fit' experience.

A possible alternative to machined prop washers:
3M Abrasives Sandpaper - Drywall Sanding Sheets
Has anyone tried them? They are availble in a variety of grits (coarseness)

mikenlapaz '1000 miles to the LHS'

What is the proper method of using this 'tool'? A) just keep going till the right tip diameter comes out the front of prop? or B) remove and insert from opposite side?

Either. Use you're own disgression depending on prop thickness.

What type of fit are we looking for? a) a little play, b) snug slip fit, or c) lets apply a little more pressure and push that hummer onto the shaft?

b) snug slip fit

Are the prop shafts on production RC motors normally a true dimension. like 5/16" shaft equalling .3125"?

Yes.

MinnFlyer is correct on all counts. A prop reamer is a normal tool for working with props. It is not just for "emergency field use." The point of it is to keep the hole centered. If you use a drill bit there is a good possibility it will grab the grain on wood props and move the hole off-center. On plastic/fiberglass/carbon props it's less of a problems, but the reamers work very well.

I've used a Fox reamer for years and haven't ever ruined a prop with it. Works great. Mine could stand to be sharpened though. It's reamed a lot of props.

I use a drill press or mill to drill propellers. Put the proper size bit in the undrilled hole then place the assemble in the press and secure. Remove the previous bit then install the size bit for the new hole and then drill. I have yet to have one off center using this concept.