6 BOLT PROP QUESTION ON TWIN
08-22-2005, 09:06 PM
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6 BOLT PROP QUESTION ON TWIN
I DRILLED MY FIRST 26X10 WOOD PROP FOR MY 3W-80 AND NOTICED THE LAST 1OR 2 BOLTS DID NOT EXACTLY CENTER IN THE HOLES MAKING THE FINAL TIGHTENING OF THE LAST BOLTS AN ARDUOUS EFFORT-- BUT I DID GET THEM ALL IN. I FIGURED I DID NOT DRILL THE HOLES VERY WELL. QUESTION--IS THE BALANCE GOING TO BE SUSPECT TO THE POINT I SHOULD SCRAP AND BUY AND DRILL A NEW ONE FOR $35.00.
08-22-2005, 09:19 PM
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RE: 6 BOLT PROP QUESTION ON TWIN
Enlarge the holes so that the bolts don't bind. The prop centers on the 10mm shaft, not the location of the bolt holes. Your prop is still fine.
08-22-2005, 09:34 PM
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RE: 6 BOLT PROP QUESTION ON TWIN
Be SURE you redrill that prop before you fly it... if the bolts are binding you risk shearing one or cracking the wood of the prop.
Drill from the back of the prop first... go though each hole and insert a prop bolt in each hole before you drill the next one. The prop bolt will have a little play in the hole... be sure to center the jig so that there is the same amount of play on each side of the prop bolt before drilling the next hole. Rinse, repeat. After you drill all 6 holes from the back, re-drill them all from the front. This accounts for any errors in the drill press. The prop should go on easily now.
If you didn't balance your prop (sounds like you didn't) you NEED to... I've never gotten a giant scale wood prop that was anywhere close to being in balance.. this includes Menz, Bambula, 3W, etc...
Drill from the back of the prop first... go though each hole and insert a prop bolt in each hole before you drill the next one. The prop bolt will have a little play in the hole... be sure to center the jig so that there is the same amount of play on each side of the prop bolt before drilling the next hole. Rinse, repeat. After you drill all 6 holes from the back, re-drill them all from the front. This accounts for any errors in the drill press. The prop should go on easily now.
If you didn't balance your prop (sounds like you didn't) you NEED to... I've never gotten a giant scale wood prop that was anywhere close to being in balance.. this includes Menz, Bambula, 3W, etc...
08-22-2005, 09:36 PM
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RE: 6 BOLT PROP QUESTION ON TWIN
Diablo's right, your prop is fine.
But... don't enlarge them just yet, run the motor and try them again. Sometimes the stress of running and repeated removals and installations enlarges the holes for you - been there done that. This of course only works on wood props.
Question: did you use a drill guide and drill press?
DB
But... don't enlarge them just yet, run the motor and try them again. Sometimes the stress of running and repeated removals and installations enlarges the holes for you - been there done that. This of course only works on wood props.
Question: did you use a drill guide and drill press?
DB
08-23-2005, 06:53 AM
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RE: 6 BOLT PROP QUESTION ON TWIN
Wood props compress with time and depending on brand -the compression can be enough to cause the prop holes to become smaller.
-I presume you are using the 3Wjig and 5mm drill bit.
Buy another 5mm drill bit and then- get another drill bit slightly larger -- a 13/64 or a 6 or a 7 .
When you drill a new prop -(always from the rear first) make sure the prop is on a perfectly flat surface on the drill press table. Drilling thru, makes a little hump on the otherside of the prop - scrub this off before next hole is drilled .
After drilling first hole, shove the second"pinning" bit into that hole - then drill next hole 180 degrees away.
You will have to move the "pin" to complete the pattern or you can use a shorter"pin" bit to avoid the drill chuck hitting it.
When all thru with drilling the six holes - remove the jig, switch to new larger bit and redrill. This will just slightly clean the holes .
Completed , the front washer and six bolts should drop cleanly thru all holes THEN--into a spinner backplate drilled exactly to size.
Buy a weighted handle , long wrench-- these will help you "spin" in each bolt. EKlind or others make these Tee handles.
Buy a 4mm wrench for a 5mm bolt (true for all metric wrenches) etc..
Remember to check stack height of prop and spinner backplate and front washer - you want 3/8" to 1/2" bolt into the hub
Also run a bolt into each hub bolt hole - find out how deep the hole is and never use a stack height that will let the bolt get close to bottoming.
Finally -- buy some spare bolts 5mm longer or shorter than your originals -if you plan on using various thickness of props
This will make your setups all much easier.
-I presume you are using the 3Wjig and 5mm drill bit.
Buy another 5mm drill bit and then- get another drill bit slightly larger -- a 13/64 or a 6 or a 7 .
When you drill a new prop -(always from the rear first) make sure the prop is on a perfectly flat surface on the drill press table. Drilling thru, makes a little hump on the otherside of the prop - scrub this off before next hole is drilled .
After drilling first hole, shove the second"pinning" bit into that hole - then drill next hole 180 degrees away.
You will have to move the "pin" to complete the pattern or you can use a shorter"pin" bit to avoid the drill chuck hitting it.
When all thru with drilling the six holes - remove the jig, switch to new larger bit and redrill. This will just slightly clean the holes .
Completed , the front washer and six bolts should drop cleanly thru all holes THEN--into a spinner backplate drilled exactly to size.
Buy a weighted handle , long wrench-- these will help you "spin" in each bolt. EKlind or others make these Tee handles.
Buy a 4mm wrench for a 5mm bolt (true for all metric wrenches) etc..
Remember to check stack height of prop and spinner backplate and front washer - you want 3/8" to 1/2" bolt into the hub
Also run a bolt into each hub bolt hole - find out how deep the hole is and never use a stack height that will let the bolt get close to bottoming.
Finally -- buy some spare bolts 5mm longer or shorter than your originals -if you plan on using various thickness of props
This will make your setups all much easier.
08-24-2005, 07:00 PM
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RE: 6 BOLT PROP QUESTION ON TWIN
HEY GUYS, THANKS MUCH FOR YOUR SUGGESTIONS. JUST GOT IN FROM TRIP AND SAVED ALL YOUR HINTS AND WILL FOLLOW UP. I DID USE A 3W 6 HOLE LOOL BUT NOT A DRILL PRESS. HAND DRILLED THEM. GOT TO HAVE THE RIGHT TOOLS IN THIS GAME. GOOD FLYING!!
04-29-2008, 03:06 PM
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RE: 6 BOLT PROP QUESTION ON TWIN
Man I have been looking for an answer to this for a day and a half now. So I must drill 6 holes inthe prop plus make the center fit the shaft of my new DA-85? I scrathed the hair off my head looking at this thing. Obviously my first large scale plane.
Does someone make drill jigs for these?
Kevin
Does someone make drill jigs for these?
Kevin
04-29-2008, 03:40 PM
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RE: 6 BOLT PROP QUESTION ON TWIN
From Desert Aircraft's website: http://desertaircraft.com/page.php?Page=Propellors Get the drill jig that's on the top of the page. Drill from the back side, drop a bolt in each hole as you drill.
