Author Topic: Drilling/reaming carbon props??/ (Read 2532 times)

Jim Oliver · « **on:** May 17, 2008, 08:59:37 PM »

What is the best/most accurate method of drilling or reaming the hole of carbon props?

Thanks,
Jim

gary tultz · « **Reply #1 on:** May 18, 2008, 07:26:55 AM »

Prop in a magnetic vise on the table of an accurately running Drill Press.

Jim Oliver · « **Reply #2 on:** May 18, 2008, 10:06:55 AM »

Understand the drill press scene-------wondering about piloted bits vs. tapered reamers, etc???

Thanks,
Jim

phil c · « **Reply #3 on:** May 18, 2008, 10:17:20 AM »

First, use a prop guage and make sure the rear face of the hub is flat and gives equal pitch to both blades of the prop. Once the back face is sqaure, clamp the prop down on a block of wood using a split clamp, or two clamps one on either side of the hole. Then use a reamer to bring the hole to size. If you have to take out a lot of material, like more than 1/32 in. or so, drill the hole slightly undersize and then ream the final 10 thou or so. If you are being really fussy, you need a pointed center finder and an x-y table to position the prop under the drill.

Bob Reeves · « **Reply #4 on:** May 19, 2008, 03:54:41 AM »

Whats wrong with using a standard prop reamer?

Jim Kraft · « **Reply #5 on:** May 19, 2008, 06:52:20 AM »

Hey Bob; Works for me. On most of my stuff a few thousands one way or the other is not going to make much difference any way. I have an old Fox stepped reamer that I have used for years. Works like a charm.

Randy Powell · « **Reply #6 on:** May 19, 2008, 10:57:32 AM »

If you use a standard prop reamer on a carbon prop, you won't use it many time unless you can sharpen it without changing the diameter. Carbon will dull it quickly. Same for drill bits.

Bill Little · « **Reply #7 on:** May 24, 2008, 11:48:23 AM »

I have reamed all my carbon props (for PA's) using a standard Fox reamer. If it has dulled much, I cannot notice it. I guess it HAS gotten a bit dull, though, as it takes a *little* while longer than before.

Anyway if I did have to sharpen it (I guess I will if I live long enough) it would be a simple matter.

Bill <><

Steve Helmick · « **Reply #8 on:** May 26, 2008, 06:45:58 PM »

I much prefer a tapered hand reamer to auger out props, rather than the stepped reamers from the hobby store. Scott Riese turned me on to that. It is possible to get a better fit, but takes a little more patience, as you have to work up to the right size. Experience helps, actually. One size fits all! Buy it at your local hardware store.

I haven't yet used the hand reamer on a carbon prop, but would do it in a heartbeat. A drillpress sounds like a scary deal...especially with a carbon prop. The carbon props probably don't have a whole lot of CF tight to the hole, so you'd mostly be cutting epoxy, not a big deal.

IF you have to drill a CF prop out for a shaft extension, then you'd better ask Randy Smith how to go about it! I'd like to know, but I'd also like to avoid that excitement....

Steve

Jim Oliver · « **Reply #9 on:** May 26, 2008, 09:32:14 PM »

While waiting for info to be posted, I talked to Randy about drilling the carbon Bollys.

He advised against the tapered reamer because the hole would be too large on one side (front or back) of the prop. He suggested the stepped prop reamer, rather than drilling. I know from experience that it is difficult to precisely enlarge a hole by drilling and maintain the exact same center---at least with my skills and my drill press.

So--------I haven't reamed them yet, but the time is rapidly approaching.

Hopefully,
Jim

Jim Oliver · « **Reply #10 on:** May 27, 2008, 01:19:24 PM »

Hey Ty,

No broken carbon props----yet!!
(None of the other guys have been brave/crazy enough to use them, I'm the test subject.

)

But, thanks for the idea.

Cheers,
Jim

Steve Helmick · « **Reply #11 on:** May 31, 2008, 09:59:34 PM »

The tapered reamer is NOT a problem, honest! Still, I haven't used it on a CF prop. Scott probably has, tho. You might ask him, or ask Leo to forward the message.

Be aware, however, that some stepped reamers are inch, and some are metric, so you may need one of each, depending on your engine collection. I think for safety, a hand reamer is definitely the way to go. Safer for you and your prop.

Steve

Jim Oliver · « **Reply #12 on:** May 31, 2008, 10:42:30 PM »

Hi Steve,

I have tapered reamer as well as inch and metric step reamers---all new and sharp, ready to be dulled.

Anybody got any broken carbon props for me to practice on---wood props are too easy.

Cheers,
Jim

raglafart · « **Reply #13 on:** June 25, 2008, 12:51:37 AM »

Actually a duller drill is a better bet, it's far less likely to snatch and pick up if. Don't try and bite it all in one go. If you use a drill press, just make sure you have a stop so if it does pick up, your fingers aren't going to get sacrificed. I've done lots of carbon props from my Pylon racing days and always used the drill press, but like I said a sharp drill isn't such a good thing and the same applies when drilling glass reinforced props too!
Check out the tool supplies on the bay and you should be able to find the reamers you want which is the best way to go, use the slowest speed.
Cheers JG

Wayne J. Buran · « **Reply #14 on:** June 25, 2008, 04:43:13 AM »

Using a drill to open up a hole to a larger size is bad practice no matter what material you are working on. The drill will catch with its corners and you will wind up with a larger hole than needed or an accident. Suggest you hunt up the reamer you need. For a prop I would suggest a hand reamer, they have longer entering tapers. Inexpensive ones can be purchased at Harbor freight. Machine reamers have a shorter chamfer and can be used on a drill press rather easily as long as the prop is properly located and held. Reamers always hold closer to nominal size.
Wayne Buran
Cleveland Twist Drill Co
1967-1993

john e. holliday · « **Reply #15 on:** June 25, 2008, 07:22:08 AM »

I have always used a tapered reamer since day one of modeling competition. You have to ream a litle from both sides of the prop too keep from making the hole too big. As stated you have to creep up on the fit. Mine are reamed to where I can spin the prop onto the shaft without too much effort. DOC Holliday

phil c · « **Reply #16 on:** June 25, 2008, 08:53:20 AM »

the question was "what is the best/most accurate method" Hand reaming works, but is sure is a pain. A tapered hand reamer will work, but it certainly isn't the best or most accurate method. Heck, I've done it with a #11 Exacto knife. But if you've just spent $30 or so on a carbon fiber prop I'd want to take a little extra care and do it right in the shop.

don Burke · « **Reply #17 on:** June 25, 2008, 10:21:39 AM »

A piloted counter bore or reamer in a drill press is probably the best thing, but as mentioned be prepared for dulling really quickly on carbon fiber, very abrasive stuff! Most use too high a drill press rpm, slower is better, especially with a piloted tool.

Alan Hahn · « **Reply #18 on:** June 25, 2008, 06:58:03 PM »

Quote from: phil c on June 25, 2008, 08:53:20 AM

the question was "what is the best/most accurate method" Hand reaming works, but is sure is a pain. A tapered hand reamer will work, but it certainly isn't the best or most accurate method. Heck, I've done it with a #11 Exacto knife. But if you've just spent $30 or so on a carbon fiber prop I'd want to take a little extra care and do it right in the shop.

Well I'm too cheap so far for a carbon fiber prop, but of course the accuracy depends a lot on how centered the original hole is. I assume it is (otherwise how do you know where to ream or drill?). My only experience has been with APC props, where they give you a "precision" molded hole on the back. What I did was machine an aluminum piece whose outer radius fits inside the "precision" molded hole, and then a 1/4" hole concentric with the outer surface. Then I drill down through the prop, the aluminum piece centering the drill bit to drill completely through the prop. You still need a piece through the "precision" hole with an inner diameter equal to your prop shaft. But at least the off center (sometimes) through hole has been drilled to not interfere with the prop fit.

Sorry to perhaps hijack the thread, but as you can probably tell, I was pretty proud of my little fixture (need to amortise the mini lathe now that I am tending to electric and not venturi/spraybar machining!).

phil c · « **Reply #19 on:** June 26, 2008, 08:14:36 AM »

Alan, a little drill jig like you made is an excellent idea. Lining up holes using a drill press without an x-y platform on the table is a really iffy.
You can use tools like this to find edges and centers. They are pretty cheap, at around $10 a piece from places like MSC-Direct.com
If you have a mini-lathe you could probably bolt a 90deg angle plate onto the carriage and clamp the prop to it, using the centerfinder to get it lined up.

Author Topic: Drilling/reaming carbon props??/ (Read 2532 times)

Alan Hahn