flex shaft problems....

[screwball]

i keep on having problems loosing flex shafts on my boats and im getting tired of it.

i always tighten down everything and double check all the screws or bolts but then outta the blue the boat just stops and i can hear the motor or engine keep on reving but the boat isnt moving.
i just want to ask you guys if you have any tricks on making sure that the shaft doesnt fall out. the only thing ive thought of is putting a drive dog on the shaft in front of the stuffing tube to keep it from going any further but idk...


thanks!
James

[domwilson]

That sounds like a good idea but I would try to find out why you keep loosing shafts. Maybe a wrong or bad coupler? Are the ends of your shaft solid.....that sounds bad...soldered?

[screwball]

yea all of my shafts are soldered and the couplers are all the correct size. they just seem to keep on loosening up and i have almost zero vibration so ive ruled that out...

[egneg]

I have had problems with wire drives so I use wheel collars from the airplane section.

[jlr3rd1]

i had same problem i replaced the colletor nut, and had same problem??? i used 3m threadlocker blue and had not had problem since

[Fluid]

The safety solution is to use a wheel collar on the cable up tight against the coupler. I assume you are using a set screw coupler - IME these are prone to losing cables unless they are designed and tightened correctly. You may think you have no vibration, but believe me when the prop blades slap the water they set up some awesome driveline vibrations. A collet-type coupler may fit your style better.





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[screwball]

thanks for all the replies guys!!!!
can someone throw me a link to the wheel collar
and ive lost cables on both style couplers


thanks
James

[Rumdog]

If you use a collet type coupler, there is not any way you should lose the flex....If it's the right size. I'd dpuble check the setup. I've never lost a flex using a collet. Pics?

[screwball]

the collet one was on my nitro so i was thinking that it was possibly the vibrations from the motor loosening it...

[domwilson]

Maybe a short piece of tight fitting fuel tubing on the flex before the strut? It could easily be removed for maintenance and should prevent you from losing the shaft. Just an idea.

[Fluid]

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD833&P=7

Fuel tubing can work in a pinch, but if your shaft rpm is high it can balloon out and break.

Collet couplers need to be lubricated to work correctly. A touch of Never-Seeze or similar anti-galling lube on the threads allows you to tighten the nut more, giving a better grip on the cable. But it is possible to over-tighten and break a collet, just like you can strip a setscrew.






.

[screwball]

fuel tubing is a great idea!!!! and i`ll try that on my collet couplers thats also a great idea! lol


thanks guys!!!
James