Friends..one of the great worry of a boat modeller is about the coupling between motor and drive shafts..even i was in trouble to find a good easy solution for a coupling..we can buy a coupling from hobby store..is far expensive..and can make one from a lathe..but must wait for their favor..especially for a tiny minute work like this...so i found a simple effective solution..and tried this year in ship model competitions..proved very successful..we can make any coupling to any motors...with ease..in minutes...

collect some bicycle spoke nipples, in various sizes..its very inexpensive..but strong..and yes non rusty as it all are made of brass...

collect some stain less steel bicycle spokes in various sizes..also inexpensive...

now i am planing to fix this EP 400 motor to a patrol boat...so drive a nipple with hammer, on to the shaft while placing the back of the shaft on a bench vise...
after making sure it is straight..apply some industrial cyano glue in to it...

cut a piece of brass rod, in to appropriate length, and make sure it is tight with the driven nipple...

apply cyano to it...
place a second nipple in same size to the opposite side...

now wait to dry...
can see how simpleit is...
we can drive in a spoke, in to the thread of the nipple as shown..make sure thread is ok...

now drill a hole on nipple as shown..a 2mm bit is good, for this tiny shaft...
take a third nipple and thread to the desired spoke as shown...

start to thread in the spoke in to the motor...

and tight the counter nipple with nose pliers...drop some cyano...

now its ok..
time to fix on the craft....

we can make any size of coupling from bicycle nipples..can drill a hole along, so can lock it with a tiny bolt...firm...

as no ballpoint tube or silicon tubes are used..no issues with heating up.... :-)) :-)) :-))

sir you are

Another stroke of brilliance from Roopesh! 

Hope the radio is working well

A Very Happy New Year to you! 

i want 8mm shaft coupling. Any seller ?

Sir i have quoted you.
please check your email.
Regards
Nilanjan paul

www.pline.in

sir i want 4mm motor to 3mm shaft coupling for boat

Excellent and simple way , great roopesh