I need to drill a prop 10mm. My prop reamer doesn't go that far. How do you guys do it.

I had to go out to my shop and root around in my flight box looking for my reamers, I found three of them. One is a smaller one for my small glow engines. It's a three step reamer. Then I have another one that is a four step reamer, as I recall it is SAE. Then I found a bigger reamer, a three step that goes up to 10MM. I either bought all three of them at my LHS or Tower?? I have had them for a number of years so the old memory is a bit off. Off the top of my head an M12 drill bit is 10.2MM. Knowing what I have been going through I wouldn't trust anything off the top of my head.

Fox makes a 10mm
http://www3.towerhobbies.com/cgi-bin...?&I=LXNL18&P=7

or go with a tapered reamer http://shopping.yahoo.com/indoor-liv...tapered+reamer that can be any size

Duh!!!!!!!! Use a 10 MM reamer. Simple as you are.

I use the Fox reamer and it is very nice and good quality. Just make sure you start one side then go around to the other side and that keeps the hole straight. Works great.

Ditto...

I ordered mine from Tower....

If I were to drill them, I'd be using a drill press with a perfectly level table to keep the drill straight. Would even check with a square to be sure..

Hand drilling is a no-no... Use a reamer instead...

Cheers

Don't forget to balance after you drill/ream.

Do I balance on one foot or what.

Great Planes has a metric prop reamer that reames 1/4",7mm,8mm,and 10mm holes. Tower Hobby sells it for $14.49 (pt #GPMQ5007) and also has an inch size reamer that does 1/4",5/16",and 3/8" holes (pt#GPMQ5006) also @ $14.49. I have them both and they work well.

guess I better order one. I have the inch one. Don't have the metric. I'm just an SAE kinda guy.

Good one!

Hi goirish
It looks like you have the right answer. Back around 1973 or so, when I began in this wonderful hobby, I had the same problem as you have. I was connected with a machine shop then. I had the machine shop make me a step drill. I am looking at the drill now. The first 5/8 length of drill is 1/4" diameter, and the rest of the drill is 3/8" diameter. I cannot remember using that tool much. I have a hand step reamer also, but do not recall using it in the past 20 years or so.

Another suggestion: Try Irwin Unibit # 11102 about $20.00




http://www.google.com/search?q=High+....,cf.osb&cad=b

I prefer to use different sized round tapered files. I do own a 5/16" reamer from my OS four stroke days. Twist the round file backwards. Works for wood and FRP props. Takes a little longer but guarantees the hole is centered. Swap sides of the prop because yes the file is tapered. Don't over do it or the hole will be too large. This process is slow and therefore accurate.

To hell with reamers or stepped reamers! Use drill bits. Drill bits do a better job, and you can attach a drill to the bit and drill out the prop hole in seconds. If you need to drill out the prop hole at the field, then just attach a vise grip to the shanked end of the bit and turn the prop on the drill bit by hand. Both methods are faster than using a $15 stepped reamer, and easier on your hands too. I always drill into the back side of the prop to widen the hole. I have never gone off-center either. Since a hole is already there, the drill bit just finds its way into the center of the hole every time. You'd have to be a complete clod to screw it up or get the hole off-center.

Fox reamer = $15
Drill bit = $1.40


It's a no-brainer!

Hey Airplanes400 , meet the original l clod.[][][]

Goirish, have you ever heard the term "wood butcher" ? Well a wood butcher's two favorite tools are a hammer and a pair of vice grips. I'am not saying that Airplanes 400 might be a wood butcher because he never mentioned using a hammer, only the vice grips! You already have the inch reamer, go ahead and get the metric one too. For those of you that may wonder where the hammer might be used......after the wood butcher rounds off all the wood screw heads with the vice grips, he then drives in the screws like they are nails with the hammer!!!!

If you have a drill press, get yourself a big set of drills (numbered, lettered and fractional). They will come in very handy in this hobby. Find the drill that is closest to 10mm and drill out your prop. To be sure you get a good hole, level the drill press table, locate the prop hole (by chucking a smaller drill that fits the prop) and clamp the prop to the table.

If you don't have a drill press then a reamer like Fox sells is probably the best solution.

I do have a drill press, but I don't trust my getting it perfectly centered. Think I will go with the reamer. It is going on a 52 gas and I don't want to shake the airframe apart.

I have an AXI 5330/18 electric motor which is the equivalent of a 1.20 - 1.60 sized 4-stroke. It has a 12mm propellor shaft but the only reamer I had was for a smaller diameter than that. I don't have a drill press. So I went to my LHS and ordered one that would ream as large as 12mm. Can't remember what brand it was but it worked great. Reamed a brand new 16x8 Biella prop with it. Put it on my 4* 120 just to see what it would look like.

I use an old Masterairscrew Drill Guid Balance System.   This provides a guide to put the hole right on the CG of the prop so that it is perfectly blalance.  Positioing the prop in the guid on the balance takes some time but then you can use the proivded drill to put a clean hole through the prop hub.  No sanding tips and it's possible to get the prop blanced tip to tip and accross the hub (laterally).   Unfortunately these are no longer made so finding one is difficult. 

http://masterairscrew.com/manualinst...ructions2a.pdf

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Get a tapered reamer and you will throw all your step reamers in the trash. According to APC Props recommendations you should be using a tapered reamer anyway. Here is a link to thier site help page explaining why. Also a pic of the one I use. It goes to 12.7 mm.

Read the section that says "Engine shaft hole alighnment"

http://www.apcprop.com/v/html/tech_s...html#holealign

By the way. With a tapered reamer you don't need a SAE and metric. It does all sizes with one tool.

I'm not sure, but I think the APC website is saying to use a tapered reamer to slightly enlarge the front side of the hole after you enlarge the hole to the desired diameter by some other method. They aren't very clear.

Step drill from Bennett Built in a drillpress.



Sadly, Dick passed away and I don't know who carries a similar item.

If you aren't making a big change in hole size you can simply hold the prop in one hand, drill motor in the other and enlarge the hole..."freehand".

Drill from the back side. I fly a lot of small, oddball sized engines and keep a small drill index in my tool box. I hold the drill bit steady with a pair of pliers and forcefully turn the prop down onto the drill bit.
I don't recall any props that didn't run smooth enough afterwards....but I'm usually only using small $2 props this way.

For a large [expensive] prop, chuck a drill bit into your drill press that is an exact fit in the prop's existing hole...then use that arrangment to position your prop. You will need to come up with your own clever method of clamping the prop in place.

A drill press operation not set up correctly can introduce an off center / cocked hole just as easily if not more so than someone who is using a cordless drill with the prop in his free hand. If the change in hole size isn't too great, the bit will track perfectly through the prop without any outside influences.