Very sudden and strange prop adapter issue

So I've been flying for a while now, enough to be confident at installing props.

However suddenly I cannot get the 3.17mm adapter to tighten to the shaft. I've tried new props, differnt motors, different adapters and combinations...

The thing that gets me is, all of this stuff had worked for months until yesterday...

I know the shaft is 3.17mm since I measured it(was questioning myself and sanity), so I know I do not have the wrong size collet since a 3mm collet would NOT fit on a larger shaft.

My first thought was tolerances, but I tried 7 adapters and none worked. I cleaned the shaft and inside the collect with acetone, nada.

What gives??
 

Mr NCT

Site Moderator
So I've been flying for a while now, enough to be confident at installing props.

However suddenly I cannot get the 3.17mm adapter to tighten to the shaft. I've tried new props, differnt motors, different adapters and combinations...

The thing that gets me is, all of this stuff had worked for months until yesterday...

I know the shaft is 3.17mm since I measured it(was questioning myself and sanity), so I know I do not have the wrong size collet since a 3mm collet would NOT fit on a larger shaft.

My first thought was tolerances, but I tried 7 adapters and none worked. I cleaned the shaft and inside the collect with acetone, nada.

What gives??
The only thing I can think of is if you're using the same spinner/nut could there be some debris that's making the spinner bottom out on the shaft of the collet?
 
The only thing I can think of is if you're using the same spinner/nut could there be some debris that's making the spinner bottom out on the shaft of the collet?
I have been trying new parts. Brand new motors, adapter that came with it and new prop.

I literally have no earthly idea.
 
I can spin the prop with my hand by holding the bell of the motor. I know that is not normal.

When I tried flying it, it lacked power for obvious reasons.
 

L Edge

Master member
What may be happening is the collet thread is bottoming out in the spinner. You might have remove part of the thread. To check if right, take a regular nut instead of the spinner and try tighten onto the shaft with the prop. If it locks, remove short length of thread to solve problem.
 
What may be happening is the collet thread is bottoming out in the spinner. You might have remove part of the thread. To check if right, take a regular nut instead of the spinner and try tighten onto the shaft with the prop. If it locks, remove short length of thread to solve problem.
I will try that as soon as I find a proper sized nut.

I guessI still would not understand why this suddenly became an issue after several months of using similar parts?

And by that I mean I bought 4 motors, with adapters and if I broke one, I'd replace from my stock. Not the literal same parts, as wear would be an obvious explanation.
 

Foamforce

Well-known member
Related to east L Edge said, if you’re using a different prop that has a thinner body, then you might not be able to tighten the nut down far enough before it bottoms out.
 
Tried that. No good.

It's as if suddenly, nothing works anymore.

I've broken a motor and about 3-4 collet adapters so far.

And yeah, I'm going to sound likeI don't know what I'm doing, except I've flown at least 10hrs a week for 4 months.

Never had a prop come off, unless it broke. I'd just tighten it down normally, and it'd never be a problem.

Now? Cannot get them to stay on to save my life.

It literally defies all logic, ration and physics.

I have considered that the only common denominator is myself, so I must be the problem. However I cannot test that...
 
Related to east L Edge said, if you’re using a different prop that has a thinner body, then you might not be able to tighten the nut down far enough before it bottoms out.
I am not using a different prop.

I am not using different anything.

That are all from the same stock of parts I've successfully been using for months.

I bought 10 props, 4 motors and adapters. Have used 2-3 props of them, and 1 of the motors.

All of my testing has been on the brand new, but same model/size/batch of parts that have been sitting in my drawer.
 

Merv

Site Moderator
Staff member
I agree with L Edge.
Is it possible the hub on this prop is too narrow. You may need some kind of spacer or washer to take up the space. Allowing the collet to tighten.

Edit: I see Foamforce can type faster than I can.
 
I agree with L Edge.
Is it possible the hub on this prop is too narrow. You may need some kind of spacer or washer to take up the space. Allowing the collet to tighten.
It is not bottoming out.

I have never needed to use a washer before, and it worked fine.

I did try that earlier, just to try things and it failed. I verified that the male threaded part did not bottom out.

I just literally am at my wits end here, as nothing at all would explain why identical parts suddenly do not work.

I also do not seem to be taken seriously? As if this is my first time doing so, which it's not.
 
IMG_2292.jpeg
 

DaveM

CEO Flite Test
instead of using a collet, I use a bolt-on prop adapter attached to the back of the motor. This leaves a long prop shaft spinning in the fuselage or I have pulled the stator our, chucked it on a lathe and cut off the protruding prop shaft.
 

Foamforce

Well-known member
Sorry, we’re taking you seriously and just offering the best suggestions we can. The thing I said is something that I encountered once, so it’s reasonable to assume that it could happen to somebody else too. 🤷‍♂️

Hang on, is it possible that it’s not your collet slipping on the shaft, but rather the shaft slipping in the bell housing? There’s a grub screw that holds the bell housing to the shaft. If that’s loose, then the bell housing could turn around the shaft.
 

quorneng

Master member
+1 for "Shaft slipping in the bell housing"
Exactly my thoughts.
Never happened to me over many years rather than months but that grub screw must be there for a reason.
 
instead of using a collet, I use a bolt-on prop adapter attached to the back of the motor. This leaves a long prop shaft spinning in the fuselage or I have pulled the stator our, chucked it on a lathe and cut off the protruding prop shaft.
I may need to switch to that type of motor. I like that more, but they're not as easy to find.

Wait, these adapters fit on any motor?

How do you mount the motor, then?
 
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Sorry, we’re taking you seriously and just offering the best suggestions we can. The thing I said is something that I encountered once, so it’s reasonable to assume that it could happen to somebody else too. 🤷‍♂️

Hang on, is it possible that it’s not your collet slipping on the shaft, but rather the shaft slipping in the bell housing? There’s a grub screw that holds the bell housing to the shaft. If that’s loose, then the bell housing could turn around the shaft.
I appreciate it man.

I think this is the issue, however I stripped my Allen wrench of that size just now... Or maybe the screw.

I managed to tighten one of the motors and I'm fairly certain this fixed it.

I've been turning and testing things so much, my hands hurt and I'm also beginning to question if I'm imagining things move that aren't...

I'll just put it up in the air later and figure out that way if it's slipping.

Tiny little frigging screws those are... And it might just be that the 4 Winout motors I bought from Amazon are just too cheap...
 
So I'm fairly certain that's the issue now. I realized I could verify if the shaft was turning inside the bell housing by looking at the bearing.

Too bad I broke a motor, and basically all my prop adapters ☹️

It was getting very very frustrating, and I've spent hours upon hours researching this before posting, there's nothing about this happening.

I'll update if this truly is the issue, but this forum is awesome and I get the need to verify basics.
 

Foamforce

Well-known member
I appreciate it man.

I think this is the issue, however I stripped my Allen wrench of that size just now... Or maybe the screw.

I managed to tighten one of the motors and I'm fairly certain this fixed it.

I've been turning and testing things so much, my hands hurt and I'm also beginning to question if I'm imagining things move that aren't...

I'll just put it up in the air later and figure out that way if it's slipping.

Tiny little frigging screws those are... And it might just be that the 4 Winout motors I bought from Amazon are just too cheap...

I use a bunch of those cheap motors and they’re good for what they are. The shafts bend easily, but replacements are cheap, so there’s that.

The grub screws are 1.5mm by the way.

One way to verify the issue would be to hold the bell in one hand, rotate the prop adapter in the other, and watch the C clip on the back of the motor. If it rotates, then the shaft is rotating independently from the bell.

Also note that some of these motors have a flat spot on the shaft that the grub screw contacts. If the flat spot isn’t oriented to the grub screw, it could be very difficult to tighten it hard enough.

Good luck!
 
I use a bunch of those cheap motors and they’re good for what they are. The shafts bend easily, but replacements are cheap, so there’s that.

The grub screws are 1.5mm by the way.

One way to verify the issue would be to hold the bell in one hand, rotate the prop adapter in the other, and watch the C clip on the back of the motor. If it rotates, then the shaft is rotating independently from the bell.

Also note that some of these motors have a flat spot on the shaft that the grub screw contacts. If the flat spot isn’t oriented to the grub screw, it could be very difficult to tighten it hard enough.

Good luck!
That is true. They're cheap. Which is good, until you have an issue like this.

I did exactly that, looked at the E clip and bearing. It was def moving, but I thought it might have been the bell slipping in my hands.

Sometimes the issue is not trusting yourself.

I was considering there might be a flat spot, couldn't find one tho.

I think I just stripped either my Allen wrench or the grub screw or both...

It'd be amazing if the tiny screw actually held on, if there's not a flat spot...