How do i connect a 3.2mm motor shaft to a 4mm propeller?


Hi all,

i’m designing my first ROV and am having trouble finding an answer to this question.

The motors i ordered have a 3.2mm shaft :

I want a 3-blade prop but can’t find any with a 3.2mm hole, just 3mm or 4mm.

Is there some kind of adapter i need ?

Thanks for helping a beginner!


I found some 3.2mm finally but none fit a 4mm motor shaft.

Is it a collet adapter i need ?


Your best results may be to just epoxy a propeller with a 4mm mounting directly onto the shaft of the motor. This is what we used to do with OpenROV units before we started getting custom inserts in the props used in the kits. I would check out the Dozuki instructions for OpenROV 2.6 for an example of what we used to do.

The downside, of course, is that the propeller is now permanently bonded to the motor. It’s up to you to decide whether this is an acceptable solution.



Thanks for replying Walt.


Look at

SZ1018.8 Graupner Aluminium Coupling Sleeve 3.2-4mm
For coupling a 3.2mm diameter shaft to a 4mm diameter shaft.
Part No: SZ1018.8

Price: £3.59 (Including VAT at 20%)
Euros: €3.95 (Inc VAT) / US Dollars: US$3.86 (Tax Free)



Thanks Erland, just what i needed :slight_smile:

Cheers, Gary.