My prop won't fit on my O.S. 46 LA; the prop is an master airscrew G/F 3 series. Can I enlarge the hole with a drill. I don't know what size the crankshaft. I have a 1/4 in bit right now can I use it;or will the hole be too big?

You're 'supposed' to use a [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK248&P=ML]prop reamer[/link] as a drill bit can enlarge the hole off-center and create vibration. That being said, 1/4" is the right size.

The best tool to use is a stepped prop reamer: http://www3.towerhobbies.com/cgi-bin...&I=LXK248&P=ML

You can use a drill bit but you have to be very careful since you can end up making the hole crooked or off center. If I were to use a drill bit, I'd to it on a drill press rather than with a hand drill.

Without a drill press its hard to properly drill a prop hole straight. Most of us that have been in the hobby for a period of time have purchased a "prop reamer" to solve that problem. The prop reamer is a hand operated tool like a drill, its shaft is stepped to the proper crankshaft diameters sizes. An inexpensive handy tool well worth the purchase.

An ordinary drill bit doesn't leave a truely round hole either. Use a reamer.

thanks ya'll; I'll go buy one

You also can put the prop reamer in the drill press. Be sure and use the lowest speed and take it slow. Sure is easy on the hands!!

Happy Landings!

umm, ur doing it wrong? [X(]

serously there is this prop reamer thing, that is what U need to get. so many gadgets to buy so little money to spend[:-][]

I second the Prop Reamer! Do NOT use a drill or drill press. I screwed up a few props by using a drill when I first started in this Hobby... sure it looked good and I thought I had it right, until I noticed I took a lot off the prop to balance it. [:@]

Here is a test for all you people who think a drill press or hand drill is the way to go: buy a brand new prop and get it balanced right out of the bag, then drill your hole with the drill and re-balance... what happens? Yep you guessed it, your prop is out of balance... meaning your drilling wasn't 100% right on.

When I read using a drill press or hand drill I nearly choked on my coffee![sm=48_48.gif]

There has also been a lot of talk about a batch of APC props which were manufactured with the prop hole off-center. The molded in boss on the rear of the prop was accurate so folks used a bushing which fit inside this boss to redrill an accurate prop hole.

I have a tool that looks like a prop reamer but it has no " steps " just one long taper. I used it to ream out the prop for the new TTPro .61 I'm just breaking in. I reamed equally from front and back.

I had thought this was a prop reamer but now that I see mention of a " stepped " reamer should I not use this tool? It was one of the many things inherited from step dad...

Steve

A tapered reamer will only give you a small contact patch at the correct diameter. The rest will either be too big or too small. Ditch the taper ream as far as props go. There are other places it can be used though. Best is for gradually enlarging holes in thin material, metal or plastics where a taper won't matter.

Ok guys, I guess that now is the time for you to make me look foolish. I have owned two or three stepped reamers, some that I have bought and some that I have inherited. I have the same problem with all of them. The resulting hole is either too large or too small. I have tried to use them on engines from .15 to .90 and different manufacturers all with the same result. It makes me wonder if they are made in two different specifications, one for SAE and one for metric. So the solution for me is to give them away to someone that is not as picky as me and just use the tapered reamer. I use a high aspect ratio reamer and carefully ream each side until the prop slides on with a snug fit and I always ream before I balance. Am I the only one that has this problem?

Yes, there are both SAE and metric prop reamers. I have and use both. But I have found a better solution. Drill bits designed specifically for drilling out props. They have a 1/4 inch pilot ground on the end of the bit to guide it. The drills come in a number of sizes - both SAE and metric. I mainly use the the 5/16 in. size. Plus I always use a drill press. The holes come out perfectly. You can find them here:

http://bennettbuilt.com/page9.htm

Bruce

There are 2 types of reamers. One is SAE ane the other Metric. Which to use depends on the prop shaft. http://www3.towerhobbies.com/cgi-bin...&I=LXG941&P=ML is for Metric and http://www3.towerhobbies.com/cgi-bin...?&I=LXG940&P=M is for SAE. You need to determine which is needed for YOUR engine. There are other manufacturers of reamers too of course.

This works if the original hole is 1/4 inch. Not all props are. Note their offer to grind drills with custom sized pilots.

Both links are metric.

Oops - Corrected.