Jonathan Ott

My Feedback: (25)

I have a new DL50 and need a prop. I don't have a drill press to drill it myself, and I figure with all the DL50's out there that someone has to have progressed up to a 23" prop and does not need their 22x8 any longer.

Thanks,

Jon

Tired Old Man

My Feedback: (1)

It would be much less expensive in the long run and a heck of a lot more practical if you bought a DA drill jig instead. It's thick enough that you could use a hand drill to do your own props. You just need to go a little slower. Plus you get to set the angle the prop is affixed to the hub to your liking, not someone elses.

Not being critical by any means, just trying to help you along so you won't have to do this again when you want to change a prop.

Jonathan Ott

My Feedback: (25)

Pat,

I have a jig (DA Jig), and I've had a couple other folks PM me about how they've done it without a drill press. As a matter of fact, Vic Aponte dropped me a note about how he does it and it reads pretty logically. I may give his way a try.

Jon

skiman762

Practice of some scrap wood first that way you get the feel for how the process works before drilling the prop

Bob Pastorello

My Feedback: (198)

Here's a current thread on this topic - http://www.rcuniverse.com/forum/m_7240436/tm.htm

pe reivers

Not much of a solution is it?

If you have a prop, and you have no drill jig, here is the drill: (pun intended)
You need a drill press for this!
Fit the prop washer to the prop mounting face, and take good care that it is centered to the prop predrilled mounting hole.
Take a drill bit that exactly fits the prop washer holes, and pre-drill the back of the prop about 1/8" (3mm) deep.
Remove prop washer, and drill all the way through from the back, using a plain base surface.
Fit the prop washer to the front of the prop, and check the bolt pattern fit. If the fit is not to your liking, fit one screw, and ream drill from the front (using the prop washer as a drill guide) until the bolts slide right in.
when satisfied, drill the holes a bit larger!!!! They are not meant to keep the prop from turning on the prop drive shaft, but to allow the bolts to pass through without adding shear forces to the bolts.

Without a drill press, you need a quality drill jig to guide the drill perpendicular to the mounting faces. The rest is the same as before.
I would not recommend this.
A drill press is a must have if you want to drill your props, but if you have a drill jig it will do. Use very sharp drills, and relieve the bores generously for at least 1/128"' oversize so the bolts slide in and can be tightened without binding.
Go easy on all drilling phases, and take your time.

Once the props are fitted, check torques frequently. Those who did not do that, all report broken prop drive bolts!!
Big gassers have their own set of rules that must be adhered to.

Tired Old Man

My Feedback: (1)

40 inch pounds for prop torque. Most people do not realize they are seriously over torquing the prop bolts. Most prop bolts are one of the following sizes: 8-32, 10-32, and 5mm. McMaster-Carr sells some very nice 1/4" drive, short allen key sockets in the right sizes. [link]http://www.mcmaster.com[/link] You get to do your own search for the product, but the link will get you started. Then locate a 1/4" drive inch pound torque wrench somewhere. Harbor Freight frequently sells them for about $20.00.

Please don't write that all that stuff costs too much. Tossing a prop in a hover or shearing off the bolts and having the hub repaired costs a lot more.

pe reivers

Thanks for the data Pat.
I just use my machinist's hands and try not to over-torque. Torque wrenches do a much better job.

buck1856

My Feedback: (49)

Do yourself a fovor and go buy yourself an early christmas present from harbour freight.Buy a model #813B drill press.I bought one a while ago on sale for $39.95.5 speeds,belt drive,ect...Bench model,ive even used it for small milling jobs on flywheels for my weedies and it works great.Theres a lot of other uses for it also,you can use flat sanding,grinding discs,oval or pointed grinding stones,ect...You can even do jobs for your neighbors that dont have one,charge them a couple dollars and it will pay for itself wether you use it a lot or not.Drill presses are really handy to have.You could even buy a polishing disc or wheel and polish your hubs and spinners.

mitchmcf

Or if you want you can get pre drill props here just get them for a DA. [link=http://www.troybuiltmodels.com/Propeller.htm]TBM Propellers[/link]

dogshome

I have a hand held variable speed battery drill, a steady hand and some sharp bits. Put the washer on the prop on the motor, mark the holes with a pencil, take the prop off, drill with a 2mm bit and then follow through with the 4mm or whatever.

What's the problem [sm=bananahead.gif]

pe reivers

You'll know the problem as soon as you follow your own advise.

Bob Pastorello

My Feedback: (198)

Yep. That "drill through the washer" deal is a way to waste enough money to BUY a drill press pretty quickly by screwing up props. Of course, like many, ** I ** had to learn that by trying to do it in spite of advice. But I only had to do "one"....

pe reivers

I do drill all my props using the prop drive washer, but I see no way of doing it freehand the way as described by Dogshome. I use a drill press, and that works very well after tightly fitting the washer to the prop using the central bolt.
Freehand drilling only works with a drill jig to guide the drill exactly perpendicular to the prop face.

thevirginian

Yes, but the jig only works somewhat reliably, as long as it is thick enough to guide the bit perpendicular thru the prop. As soon as you have a little clearence between the bit and the holes in the jig you are off. You will not be perpendicular. If you are tight enough (jig holes and bit) than you run the risk off opening up the holes in the jig with the bit. Either way, I am 100% with you, pe receiver: A drill press is a must, if you want to drill a prop accurately, so it stays balanced on the hub. Otherwise no need to balance a prop in the first place.

pe reivers

The drill jig is made of hardened steel so it will last you a life time, and yes, you have to use a drill that fits the jig. A decent set will cost you, but will do the job for quite a few props.
The prop washer and drill press is much easier.