Reaming a Prop
 

If after I finish reaming a prop and it now has "wiggle room" on the engine shaft, are they ruined?

RE: Reaming a Prop
 

Well, it should be a good tight fit. Did you use the right reamer? They come in both metric and SAE. You should carefully match the shaft size with the reamer. Depending on how much "wiggle" room you have, it may be usable. If it's to much, well, you get the idea.

CGr.

RE: Reaming a Prop
 

As CG said, metric and sae. The wiggle can be fixed with masking tape around the crank shaft.

RE: Reaming a Prop
 

There go 2 brand new 3 bladed 12/8 props. I used the right reamer and the right size and my drill press, but when they were done, I saw a small lip inside each and took both off.....now they wiggle....[:@]

RE: Reaming a Prop
 

Drill press for your prop reamer?

Most folks in the hobby use a hand-held reamer such as this one: http://www3.towerhobbies.com/cgi-bin...?&I=LXEGH7&P=7

You can "feel" the reamer working. It has three separate sizes. You work the prop to the size you need, by hand, and that's it. It is very easy to do and is made for the hobby.

CGr.

RE: Reaming a Prop
 

The new ones have removable handles and even suggest a drill press.

RE: Reaming a Prop
 

Even your link says "Can be used with a drill press for extra precision"

RE: Reaming a Prop
 

Take it from experience. Do it by hand. You will be much better off. I've reamed many many props and not one has been "wobbly".

CGr.

RE: Reaming a Prop
 

I think it happened when I tried to get rid of the LIP I saw inside.

RE: Reaming a Prop
 

Many spinner backplates come drilled large with a set of shaft adapter spacers. If you know anyone who has some of these shaft spacers, just ream to fit one of those.

RE: Reaming a Prop
 

Look at the site Dick brought up. Notice the one shown has three steps in it, that's SAE. The next one down has four steps in it, that's metric. I only know one person using a drill press to ream his props. His press is set up with a jig that holds and centers his props, works for him but he spent a lot of time getting that jig set correctly. I buy new props, balance then toss in my flight box or prop box. When it's time to use a new prop is when I ream it, not ahead of time. I never know what engine the prop will be used on so I don't know the shaft/crank size ahead of time. It only takes a couple minutes of swearing, I mean reaming out at the field to get the job done.
Just a couple twists of masking tape will tighten the prop up on the shaft. That's what the roll of masking tape in the flight box is for.;)

RE: Reaming a Prop
 

There ya go, rocad. Listen to us. We have all done this before. It's not rocket science.

CGr.

RE: Reaming a Prop
 

I use a single tapered reamer from the back and it works fine. All the hole does is locate the prop on the hub. Once the nut is tightened it does nothing. For the original question, I'd be surprised if we're talking about more than 2-3 thousandths of wiggle here. The imbalance that would be caused by that is less than the props themselves bring into the equation.

RE: Reaming a Prop
 

Well Dick. I did at one point start knocking out the handle in one of my reams with big plans on using my press. It wouldn't knockout!!!!!!!!:eek: I was getting real sick of reaming out big wood props for my gassers. Those critters are thick and that wood is hard!!:eek: Either that or my hands have gotten old?:eek: Maybe a dull ream??

RE: Reaming a Prop
 

Not to be a jerk but have you used a pair of digital calipers to double check the actual crank size of the engine? You may have an fluke engine with a slightly undersized shaft.
You can get a cheep pair at Manards and they prove handy for the hobby. I checked them ageist my dads machineest grade Mitutoyo calipers<strong id="yui_3_3_0_1_1325475079126394"> [/b] and they were right on. <strong id="yui_3_3_0_1_1325475079126394">
[/b]

RE: Reaming a Prop
 

I once had a Graupner 3 blade prop given to me that had been reamed to a larger size than I needed. I was able to use 2 short pieces of brass tubing, one inside the other, to fashion a sleeve to make up the difference. Just find the tubing size to fit the prop shaft and work it from there; may need two or three layered sizes and the prop reamed a bit larger to get a good fit.

RE: Reaming a Prop
 

I''ve solved this problem on 1/2 A's with a piece of heat-shrink tubing on the prop screw. Works fine.

RE: Reaming a Prop
 

If its a very slight wiggle I woulnt worry about it. Balance it till it stays in any position. When you tighten up the prop nut try to hold it centered, basically not let the sides touch the shaft. If you have a significant wiggle these are your options;
1. The easiest is to dry your tears and buy a
new one, lesson learned.
2. Try what has been suggested above. Definately use a reamer by hand from the back!
3. This is hard and a last resort. And if your super cheap and can't admit defeat like me! I've filled in the hole with epoxy such as five minute. Find the center ( measure the hub an x, and from tip to tip. if it's it's not wood you can use the rings on the back an measure the center) and start with a small drill bit till I get the reamer started. If its off a fraction it's ok because you more concerned with the balance point shifting when you mount it. Blade track of a 16th or two will matter little on an R/C.
4. Paint it up all shiny with an old spinner painted ip all shiny mount it to a piece of finished wood and you have a nice static display! I have a room full of them, like a big game trophy room! :D

RE: Reaming a Prop
 

If you over drill the prop, you can take one (or even two) pieces of heat shrink tubing and put on the prop shaft to make up the difference. This is far better than masking tape and most heat shrink is pretty tough. Keep in mind that if you have over drilled the prop and in the process de-centered the hole then the prop is for all practical purposes shot, no way to easily fix that.

Happy Flying!

Loopman ;)

RE: Reaming a Prop
 

I'd like to toss out one more thing... is your drill press table square to the drill? I'm wondering if your table was slightly out of square (tilted), or if the prop hub rocked (there's not much base area there) while you were drilling?

For the record, I have used a drill press but for the most part I use them by hand. If you do use a drill press, I would recommend that you find a way to clamp the prop hub securely to the table so that it doesn't rock.

Greybeard, what was that site that you referred to in Post 11?

Just my $.02

Bob

RE: Reaming a Prop
 

While we're on the subject, there used to be a prop balancer that would let you balance the prop in a jig to find the true CG. You would then drill it out with a reamer. It's out of production now. I think it was a Robart or a Master Airscrew.

Has anyone used one of these, and have you seen one for sale? Don't want to hijack the thread, just asking a slightly off-beat question...

Thanks,

Bob

RE: Reaming a Prop
 

When looking into milling attachments for a drill press I found out that if the drill press spindle gets bent it will cut holes larger than the drill bit being used.

You may want to have a look at your drill press' spindle to see if the "wobble" came from it rather than the reamer.

When you say drill press we all think a nice new one but for all we know you could be using this one and there have been lots of opportunities for the spindle to get bent in the last 150 years.

RE: Reaming a Prop
 

Amish, Have you been scoping out my shop again:D (nice pic)

RE: Reaming a Prop
 

If you have the tools, use them (drill press, mill machine)... I would never use a hand reamer on one of my $80 carbon props or even a $30 APC. I drill props for my buddies.... you can do it once correctly or go buy another one.

I always balance my props after drilling. If a prop has slop on the crank shaft, the vibration will certainly decrease the life of the engine bearings. You can generally watch an engine run and see the vibration when the prop is not done correctly. Don't forget the spinner either.

RE: Reaming a Prop
 

Hi and THANKS for all the feedback,

I'm sure it was either me (most likely) or bad equipment. As I said, after using the drill press, I looked into the new hole and noticed a "Lip", I then put the prop back in the spinning reamer and pulled against the lip just enough to get rid of it....stupid, stupid, stupid.

Lesson learned, after stay up till 3am, DONT ream a new prop the next day.

Now on to the right way....The reamer from GP ( http://www3.towerhobbies.com/cgi-bin...?&I=LXEGH7&P=7 ) has a weird transition point at each step. It’s FLAT! There's no "slight" beveled cutting edge to ease the way for the next size. After 15 mins by hand is the reason I gave up and went to a drill press (that I admit wasn’t set up 100% before hand for this...again, NOT after staying up till 3am...gezzz)….. so, just man up and go by hand starting at the back or make sure the drill press table is 90 degrees to the reamer and go SLOW? And IGNORE the LIP!

Tx