Loose fitting propeller mount

[sparks59]

I recently had a problem with a  collet type prop mount specified as the correct fit for a 4mm diameter motor shaft.

Its always a bit difficult to tighten these things, especially if the spacing back to the front of the nose cone is tight. Anyway this one just would not lock with any degree of tenacity onto the shaft.  I looked around the forums but couldn't find a suitable tip (maybe I didn't spend long enough looking!)

 

Anyway, I gave it a coat of looking at and thought about it for a few minutes...

 

The solution I came up with was to wrap a small piece of (about 220 grade) abrasive paper so that it just fitted in one layer around the collet wedge. i.e no overlap on the paper. Then I proceded to gently and evenly turn the two mating faces together, which gradually removed a small amount of the anodised coating. I then repeated this with the abrasive the other way around to take the shine off the outer body of the mount. I could have probably done both at the same time but I wanted to do it 'bit by bit' to avoid going too far and creating other problems.

 

When this was done, the two cone pieces of the mount collet pulled together just a little further, and also locked together tightly just with finger pressure, this allowed the prop nut to pull up easily and is now securely fixed.

 

Care must be taken to abrade gently and evenly, but I have had no apparent balance issues arising from this 'fix'

 

sparks

[Former Member]

[This posting has been removed]

[sparks59]

Posted by Eric Bray on 04/08/2010 23:27:04:
Or run the bare-shafted motor at a moderate rpm, and 'tickle' the shaft with the abrasive. That way it HAS to be round!

 

100% agree Eric,

I didn't do this on mine in this instance as the collet was already close to minimum diameter so I didnt want to take the risk of any shaft reduction.

cheers

sparks