Graupner E-Props DJI motor loose fit

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para9111

Member
Bought 6 E-props 10X5 for Hex. DJI motors 2212 920KV hub not round flat ends E-prop round.I found that although props fit hub if I grap prop I can still move it 0.5-1mm(best guess) while on the hub.It does not have that snug feel the DJI props have on the hub which are zero movement.Im concerned with vibration.AS well is this normal?Or did I get a bad batch of either DJI motors or E-props?I dont think its enough of a decrepancy to insert a spacer but enough to make me nervous that vibration might shake it off.Does a spacer exist to fill gaps to make the motor hub round like the E-props?
 


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para9111

Member
Thanks!!The link is incorrect but I get the idea and found them online.Great thanks.I hope when I tighten it its true to center minimizing vibration as I intend to FPV with it.These E-props cost a fortune so I was hoping they werent incorrectly bored.
 


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para9111

Member
Thanks I bought the washers found the link u intended me to see with search

I bought the washers in hopes it will tighten them up.The props are pre bored 8mm.They fit no problems but I feel they are a slight bit loose.Slight play when you jiggle it up down.Im talking .5mm.Im not sure if its because the hub is not round and props are or props are bored touch too big hubs touch too small.It concerns me because when I tightem them up are they going to be true to center or slightly off causing vibration.Perhaps Im being over critical but I was expecting them to me snug fit true to 8mm.I need a caliper to confirm bore /Hub working on it.Since ordered a new batch from different seller just in case.
deanot said:
Did you buy them pre-bored? they should be a nice fit on the shaft if they are the correct size bore. Sorry about the link, I was posting that for another user and must of not copied the correct link, either that or he got your link... lol

This was the link I was trying to show you.... Third item down I think. https://www.gothelirc.com/shopdisplayproducts.asp?id=156&cat=Graupner+Props
Click to expand...
 

Olemil

Olemil

Member
I bought a set of Graupner 10x5's also and they too are not a snug fit on the DJI motors. I did measure them with calipers but can't remember the numbers off hand, the prop bores are truly larger than the motor shafts. Also I bought a set of the washers linked above and they fit even worse (I.D. bore) than the props. I found some hardened washers in my bolt bin that are a nice slip fit on the motor shafts so I used them. I hate to say it but I actually like the DJI 10x3.8 props very well when I am running 3s. Update: I dug out my calipers and did some measuring. Seems the props are spot on, it's the motor shafts that are small! DJI 2212-920 motor shaft O.D.=7.91mm, Graupner 10x5 prop I.D. bore=7.99-8.00mm, spacer/washer I.D. bore=8.50mm.
 
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OneStopRC

OneStopRC

Dirty Little Hucker
Interesting findings, I have just ordered 4 sets of 9x5 Graupners for my hex, yeah I know, but they only sold them in 4's. So I have a couple of spares... Shall be interesting to see how this works out.

Just in case someone is looking for Graupners... you can get them from Team Blacksheep website for $30 for 4 of them! yes... $30 for 4.... http://team-blacksheep.com/products/product:122
 

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para9111

Member
Well that's nice to know Im not going crazy and yes you are correct the Motor hub is small seems to be a batch out there slightly off.Curious where did you get your motors?Mine are from multirotorheli.Im making an assumption here but my motors are not suppose to be 7.91mm correct if someone can help me out on that.Whats weird is DJI props fit snug so now Im thinking Im measuring incorrectly.??
 
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OneStopRC

OneStopRC

Dirty Little Hucker
I have seen many people say the shafts on DJI motors are not 100% machined the same. Recently I bought some of the newer 10" props, some of them was a real snug fit where I had to force them on the shaft and some was a little loose.... So I swapped them around and the same thing on some of the motors happened, I was thinking it was maybe a bad mold on the props, but that was not really the case. Seems like poor machining practices or slop in the machine cutting the diameter of the shaft, same issue with thread depth on the shaft too.
 

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para9111

Member
I guess I might have to buy 4 new motors.Im not comfortable using washers in case its not centered on the hub or moves in flight.I believe even the smallest spacer would be to big.I could also use a spacer and re-bore the props to what I need.Doesnt sound like a lot of fun.Oh well.Open for suggestions.
 

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tstrike

pendejo grande
I wouldn't get so anal over the milling accuracy's of a dji motor. Live with the slop (7.91mm vs 8.00mm, really?) and go out and fly. Besides, chances are the motor barrel's aren't 100% round anyway-they're freekin dji lil reds, like a sleezy girl everyone hits but nobody marries, you'll have plenty of opportunities to change motors down the road.
 

Olemil

Olemil

Member
My motors came in an ARF kit from UAV about 3 months ago. I did replace one motor a few weeks ago, might have to pull the prop and see what that shaft measures. I too noticed the DJI 10x3.8 props fit tighter on some motors and not others. I thought it was the props all this time too but after reading deanot's post I am leaning towards inconsistent motor shaft size also. Either way the DJI's do fit the shaft tight no matter which motor you put them on, no chance of moving around for sure. I bought the same 9x5 Graupners from tbs too, the shipping isn't too bad to the states and only takes about a week to get here. My advise to anyone who wants to use washers to shim up the prop hub thickness, best bet would be go to your local hardware with a motor (if you have one not mounted) and find the right size washer that fits snug on the motor shaft.
 

Olemil

Olemil

Member
tstrike said:
I wouldn't get so anal over the milling accuracy's of a dji motor. Live with the slop (7.91mm vs 8.00mm, really?) and go out and fly. Besides, chances are the motor barrel's aren't 100% round anyway-they're freekin dji lil reds, like a sleezy girl everyone hits but nobody marries, you'll have plenty of opportunities to change motors down the road.
Click to expand...
Exactly, if anything I would worry more about the washers being half a mill larger I.D. and being off center. I'm sure the motors are no where near precise and like you said the cans are no doubt way off balance anyways.
 



OneStopRC

OneStopRC

Dirty Little Hucker
Oh yeah, good point tstrike.... bear in mind, one you put graupners on your DJI motors, you will loose the keying that the old props had with the motors. So you will need to make sure your prop nuts don't come loose and this is where the nylocks can help. I think they are 6mm X 1 thread nylocks if I am not mistaken? which I need to go out and get myself.
 



Olemil

Olemil

Member
I could never find the nyloc nuts at our Home Depot. Only locking metric nuts they have are the ones that are dented on three of the nut flats. Didn't want to go that route because it distorts the threads of what ever you are screwing them on to.
 


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