So happy now that I know my nuts won't fall off
- Thread starter BerndM
- Start date
Post crash: I placed the washer from motor onto the Carbon Fiber prop to see how it would fit. I actually had to place the washer upside down in order to clear the hub (the point where the blades begin to twist).
I hear a lot of good things about Graupners. I also looked at the hub of the Graupners and they appear to be larger than the hubs on on my fatal props. I had my washer under the prop and the Nylock nut on top of it. I had just enough surface area for the 6mm nut to seat.
I will build again and secure my APC props with Nylock .
I'm just thankful I was over trees and not over someone's property.
I hear a lot of good things about Graupners. I also looked at the hub of the Graupners and they appear to be larger than the hubs on on my fatal props. I had my washer under the prop and the Nylock nut on top of it. I had just enough surface area for the 6mm nut to seat.
I will build again and secure my APC props with Nylock .
I'm just thankful I was over trees and not over someone's property.
lol...yeah... I only bought six for my Hexa. sigh...
BerndM
Member
If you are using a Nylock type of nut, then, depending on your choice of prop, you may not have enough threaded shaft sticking up thru the prop for the Nylock to grab on to.
I use the Graupner 10x5 props and do not use a washer, but then again I don't go crazy on the torquing either.
Blackdragan
New Member
Bernd,
In your above quote, you mention that you need to use a 6 or 8mm washer with the Graupner 10x5 props. In your previous reply above, you said you are not using washers with your Graupner props. So which way is correct? Thanks
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BerndM
Member
Hey Blackdragan
Good catch! Oops!
In my ORIGINAL post, I didn't mention that ONE of my DJI motors would NOT allow the nut to tighten down on the prop. The Graupner hubs were all identical thickness but the one motor was machined a teeny bit differently and there was a gap of about .002". So just to keep things equal, I put thin washers under all 4 props.
Now that I am using the Nylocks, they can turn down a bit further and get good and tight without needing a washer.
So, just to clarify...with the DJI aluminum acorn nuts and the Graupner 10x5's, I needed to use washers, but with the Nylock nuts I don't need the washers any more.
Sorry for the brain fart!
Good catch! Oops!
In my ORIGINAL post, I didn't mention that ONE of my DJI motors would NOT allow the nut to tighten down on the prop. The Graupner hubs were all identical thickness but the one motor was machined a teeny bit differently and there was a gap of about .002". So just to keep things equal, I put thin washers under all 4 props.
Now that I am using the Nylocks, they can turn down a bit further and get good and tight without needing a washer.
So, just to clarify...with the DJI aluminum acorn nuts and the Graupner 10x5's, I needed to use washers, but with the Nylock nuts I don't need the washers any more.
Sorry for the brain fart!
BerndM
Member
I use a nut driver to tighten the nuts and simply hold the motor and prop at the same time with one hand and tighten with the other.
I just go until the nut is pretty snug and then a tiny scosh more. You don't want to strip the motor shaft.
I check tightness by trying to turn the prop on the motor. I think that's all that's needed.
I just go until the nut is pretty snug and then a tiny scosh more. You don't want to strip the motor shaft.
I check tightness by trying to turn the prop on the motor. I think that's all that's needed.
ChrisViperM
Active Member
Have a read at this:
http://www.bikeradar.com/gear/article/workshop-why-torque-wrenches-are-invaluable-24917/
It's not specifically about Multirotors, but you get them in all different sizes, and considering the price for a pair of Top range blades......it's a good investment
http://www.bikeradar.com/gear/article/workshop-why-torque-wrenches-are-invaluable-24917/
It's not specifically about Multirotors, but you get them in all different sizes, and considering the price for a pair of Top range blades......it's a good investment
Thanks for the article. This is good information. We never know how tight is tight. How do you know even when using "common sense"? It seems losing a prop or having them break in flight is something that often brings multirotors down. There seemed to be a debate on what side the washer went on for a minute.
Im still not sure, and I dont think there is a perfect solution. I am going to try an 8mm spacer (1mm thick) underneath my graupner 10inch props. Only problem is using a nylock on top the bolt is relatively small compared to the hub so the nut isnt gripping much of the prop. Adding another spacer on top to make the surface area bigger may not work as now there wont be much thread left on top for the bolt to go on. Could use a bigger nut that isnt nylock but then its not locked and we go back to the question how tight should it be?
If only there was a perfect solution where attaching props was 100% reliable.
BerndM
Member
Hey nosedive
You're absolutely correct in your statements regarding the Graupner props and the nylock type nuts, there is NOT a lot of surface contact between the nut and the top of the prop. I was having some trouble getting ONE of the props to lock down tight. Apparently DJI's machining tolerances are not perfect. The 2212/920 motor shaft on this one motor was very slightly different from the other 3, so that caused me to need a washer to raise the prop up a bit for a snug fit on the nut.
Something else I noticed yesterday on the Graupner props is the top of the hub has "Made In Germany" molded on it. These letters are slightly RAISED which really cuts down on the nut to prop contact surface. I carefully smoothed these letters away so that the hub is now smooth, allowing a full contact.
The Nylock nuts I'm using require a 10mm wrench. I am trying, unsuccessfully so far, to find a larger sized nut in the 6x1 size, so a larger surface contact.
You're absolutely correct in your statements regarding the Graupner props and the nylock type nuts, there is NOT a lot of surface contact between the nut and the top of the prop. I was having some trouble getting ONE of the props to lock down tight. Apparently DJI's machining tolerances are not perfect. The 2212/920 motor shaft on this one motor was very slightly different from the other 3, so that caused me to need a washer to raise the prop up a bit for a snug fit on the nut.
Something else I noticed yesterday on the Graupner props is the top of the hub has "Made In Germany" molded on it. These letters are slightly RAISED which really cuts down on the nut to prop contact surface. I carefully smoothed these letters away so that the hub is now smooth, allowing a full contact.
The Nylock nuts I'm using require a 10mm wrench. I am trying, unsuccessfully so far, to find a larger sized nut in the 6x1 size, so a larger surface contact.
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I have been looking for an M6 nylock nut that is BIGGER than 10mm wrench size but no luck
Sounds like you need a "flanged nut":
http://www.google.co.uk/search?hl=en&q=flanged+nut&meta=
Or are you wanting something that's bigger "across the flats". You shouldn't, in the sense that metric hardware is carefully sized so that the wrench size is correct fr applying the correct range of torque for that size of fastener. Really high quality tools help, as always ;-)
http://www.google.co.uk/search?hl=en&q=flanged+nut&meta=
Or are you wanting something that's bigger "across the flats". You shouldn't, in the sense that metric hardware is carefully sized so that the wrench size is correct fr applying the correct range of torque for that size of fastener. Really high quality tools help, as always ;-)