Help Please.... I've been beat up by props....
 

Ok, I'm about ready to blow a gasket.... Where can I puchase props that are pre-drilled, pre-balanced for a tru-turn spinner on a Moki 2.1? I FREAKIN CAN'T DO IT! I puchased a drill press, a 17/32 bit so the tru-turn adapter will fit in the prop and I can't for the LIFE OF ME drill a freakin hole straight enough to balance a prop..... I have to remove so much material that I'm afraid to try the prop. I've destroyed 3 props. [:@]

I want to puchase a 20 x 10 prop that will fit the above application. Any suggestions please?

RE: Help Please.... I've been beat up by props....
 

I hgave found out if you balance the prop first and off set to the hevy side when drilling it save cleaning prop blades.It does not take much!

RE: Help Please.... I've been beat up by props....
 

Hi,

I'm with you, I can't drill a prop straight either.

What I did was to buy a tapered reamer. I gently ream the prop from the back side just a little, then test for fit, and repeat until the prop fits the motor shaft. Since it is a "tapered" reamer, it self centers and will remove stock from all sides of the prop hole at the same time.

Make sure you keep the reamer "square" (perpendicular) to the prop to keep the prop true. It works great every time.

You can purchase a tapered reamer at Sears, a wood working shop, or anyplace that has a good selection of tools.

I would suggest you get a reamer that has a very small tapering (doesn't have a large diameter at the big end) so its easy to control reaming of the hole in the prop.

One caution with reamers, they are built to ream in a clockwise direction, you should never turn them counter-clockwise when reaming (it probably is OK in wood, but definetely not in metal).

I hope this helps, its an old modelers trick and still works well for me.

I hope this helps you.

Best regards,

Wayne Miller

RE: Help Please.... I've been beat up by props....
 

Could be spinner, try ballsncing it first!

RE: Help Please.... I've been beat up by props....
 

I have a reamer but it only goes to 12mm. I can't find one at 13.5mm (17/32). This may be a dumb question but do you ream it by hand or use a drill press? I may try using the reamer to 12mm then finishing off with the 17/32 bit.

Oh, it's not the spinner, I haven't even got that far yet. I'm just trying to balance the prop.

Doesn't anyone know if you can buy a already balanced and drilled prop for this application?

RE: Help Please.... I've been beat up by props....
 

Hi,

I have two reamers, I'm looking at them now in my hand, that I carry in my modeling field kit. One goes from a 10th of an inch (0.10in) (2.5mm) to ½ in (0.50in) (13mm) with the taper length being 4 inches (101mm) long. The other goes from 15th of an inch (0.15in) (4mm) to 90th of an inch (0.90in) (23mm) with the taper being 3.5 inches (90mm) long. Note: All measurements are rounded off.

I always ream by hand, otherwise you risk damaging the reamer. I also find that when I do it by hand, I have more control. The reamers come with a shaft that goes into the reamer top to be used as a handle.

I purchased one a local automotive parts store and the other from Sears.

I mostly use the smaller one (first one) for props.

Hope this helps.

Best regards,

Wayne Miller

RE: Help Please.... I've been beat up by props....
 

[:-]

Have used a taper reamer at times, but prefer a two or three fluted centering end mill/or a cap screw counter sink ( http://www.morsecuttingtools.com/countersinks/1766.html ) to use in a drill press though you can use a hand drill. The end mill has a 1/4 inch button that keeps the end mill / counter sink centered in the predrilled hole in your prop as it mills the material away..

Another cutting tool quite often used is a counterbore very similar to the countersink and are interchangeable in use...there are so many sizes available that you can virtually find most any thing you may want..or ever need.




Hint: make a cut from the back side about 1/4 to 3/8 in. deep first then flip the prop over and finish from the front side all the way through... also end mills are available from machine tool suppliers and normally used on metal lathes and drill presses... more expensive than drill bits but they will give you a perfect center and last for years. Available in most any size you might require..Check out Harbor Freight or Sears, maybe.. www.dogpile.com.. for others.

RE: Help Please.... I've been beat up by props....
 

One more solution...

You don't necessarily have to use the Tru-turn adapter. I picked up the spinner nut adapter for Moki 2.10 for the Dave Brown spinners and it works fine with the big Tru-turn spinner (3.5 in. P-51 on my Pitts M12). The Dave Brown adapter does not require counter-drilling the prop. You just ream the prop 10mm for the Moki prop shaft, balance it and you're done. I use the step reamer (sounds like the same one you have) in a drill press and just go slow. It gives a perfectly centered hole every time.

Here's a link to Chief Aircraft. They carry the correct 10mm X 1mm adapter (both long and xtra long) for the Moki 210. Tower does not. I used the long adapter on the Pitts.

http://www.chiefaircraft.com/Models/Model.html

Click the "Accessories" section then "Dave Brown Spinners and Adapters".

RE: Help Please.... I've been beat up by props....
 

Thanks for the help. I will be printing these ideas out and will consider them all. Happy New Year everyone!

RE: Help Please.... I've been beat up by props....
 

Try this, You need a drill vise. You can get them at Grizzly.com or Sears. Put the prop you want to drill in the vise. There are slots in the press table specificly to bolt down these vices. Put the bolts in but do not tighten the vise down. Carefully tighten the prop in slightly. Use a drill bit he same size as the hole in the prop as you get them. Chuck it in the press. Now comes the fun part. Without turning the press on run the bit down into the prop. You may need to giggle the prop and or slide the vise some. When the drill bit is centered and throught the prop lock down the prop and vise. The prop should be centered and ready. Just put in the drill bit and drill the prop. After drilling it then balance and you are done.

Mark Shuman

RE: Help Please.... I've been beat up by props....
 

Mark,

I can't bolt the my vice down. Either I need a new vice or drill press. My bit wobbles in the chuck anyway. The press is a POS from Meynards. I've tried clamping it down but can't seem to get it to stay.

RE: Help Please.... I've been beat up by props....
 

Hoppy, are you using a drill press or drilling by hand?

RE: Help Please.... I've been beat up by props....
 

MinnFlyer, I'm trying to use a drill press. I can't get the prop lined up good enough with the bit to make a straight hole. The vice doesn't bolt down, the table wobbles, the bit wobbles sometimes. Anyone need a boat anchor? I may have to purchase one of the end mill bits or buy a differnet spinner adapter so that I can use a hand reamer.

RE: Help Please.... I've been beat up by props....
 

You can buy a Bolly 20x10 pre-balanced carbon fiberprop from [link=http://www.bollyprops.com/bolcf18-23.html]Bolly[/link] or from [link=http://www.desertaircraft.com/bolly.html]Desert Aircraft[/link]. I don't know how big the prop hole is. However, Bolly can customize the prop to your specifications.

RE: Help Please.... I've been beat up by props....
 

Hoppy, I use a violin tuning peg reamer for my props, and it works wonderful. I also have one of the 4-step reamers that are common, and it is a POS. The violin peg reamer runs around 3/16" on the small end, and 3/8" on the big end, spread over a 5 1/2" cutter length. This tool is made in Germany, I bought mine 25 years ago and it is still sharp, I only use it on wood. The last price I saw on one was around $50 however. I don't leave this one anyplace where it can bang against other hardened steel tools, a good practice with all of your steel cutting tools. If you are interested, I'll dig through some old catalogs and come up with a phone number and maybe a part number.

Regards from old bird.

RE: Help Please.... I've been beat up by props....
 

Ok Hoppy, here's an old Machinist trick:

Don't use a vise. Hold the prop by hand. Get the drill bit close and line it up as best you can, then press the drill into it while holding it loosely. The trick here is holding it right. You don't want it to spin, or rise up if the drill bit augers in, but you want it to move back and forth, and side to side.

The drill will find the center of the hole. This method is VERY accurate.

But personally, I think your problem is not drilling off center. Try this: Balance a NEW prop, then drill it and balance it again. I'd bet a paycheck that it isn't balanced to begin with.

And don't get overly critical about the balance. Remember, when it comes to prop balancing, close enough is close enough.

RE: Help Please.... I've been beat up by props....
 

I have 2 different prop reamers ordered by lhs that is hand operated that so far has taken care off all 4" to 24" props that I've used.

RE: Help Please.... I've been beat up by props....
 

Hi Mike,

I lost the private email you posted, sorry, and don't know how to reply.

However, the name of the hobby shop is FliteCraft (one word) and they have a web page, you can get the contact information from there.

This post:

As for the violin peg reamer at $50 discussed here, the standard wood/metal reamers are available at Sears or local tool supply places for about $10-$20.

Best regards,

Wayne Miller