3 flex shafts w/props gone...

[jingalls007]

I?ve had 3 cables fall out in 2 days. I?m using 1/4? cables, Aeromaine collets for 8mm shafts.

I tighten them as tight as I can and still they manage to fall out. I silver braised one Shaft to see if that corrected it, but no-go. I don?t recall Octura collets giving me this much trouble.

Any ideas on what I did wrong?
Thanks doodes!

[Ken Haines]

There are several other collets to choose from that are very good.
Lehner, TFL, and Speedmaster make very good couplers with very little to zero runout.

My concern would be that no matter what coupler you choose that you should be using
some type of shaft retainer. On .150 and .187 shafts a simple piece of fuel tubing usually works
for a coupler failure or simply not completely tightened shaft. For the 1/4" cables I always use
a shaft collar. McMaster Carr has them here is the link:

https://www.mcmaster.com/catalog/126/1311/

Pretty cheap insurance to retain your cable and valuable props.

[fweasel]

I don't use shaft collars as Ken suggested, but I do use high quality collets. Depending on the application and space allowed, I like the MBP and LMT collets the best. no run out issues and you can tighten them down with a proper set of box wrenches. The only time I had trouble loosing multiple cables was when I had not replaced a worn collet. The collet was relatively new, but a flex cable had previously spun in it when I had not tightened it properly. New to the hobby at the time, I did not realize that once a cable spun/slipped in a collet, both the cable and the collet lost mating surface material and should both be replaced.

[jingalls007]

There are several other collets to choose from that are very good.
Lehner, TFL, and Speedmaster make very good couplers with very little to zero runout.

My concern would be that no matter what coupler you choose that you should be using
some type of shaft retainer. On .150 and .187 shafts a simple piece of fuel tubing usually works
for a coupler failure or simply not completely tightened shaft. For the 1/4" cables I always use
a shaft collar. McMaster Carr has them here is the link:

https://www.mcmaster.com/catalog/126/1311/

Pretty cheap insurance to retain your cable and valuable props.

Thank you for that Ken! Steve?s been out of 1/4? cable savers for months. I just ordered from MC master. I really appreciate the help on that 🙏🏼

[Jesse J]

A trick with any collet to get another 1/4+ turn is to use anti seize grease.
This seems counterintuitive but no collet with this treatment has ever let loose on me.

[Fluid]

To be clear, the grease goes on the threads and the conical collet seat. Not on the cable......




.

[RaceMechaniX]

I have had a lot of issues with the fits of the Aeromarine collects in recent years.
While the MBP and LMT are very high quality, the aluminum tends to deform and not hold over time especially if you crank on the hard.
For a similar collet type coupler like AM, I would recommend Speedmaster. They have made very high quality couplers in recent years.

For high power and cables that are slightly undersized I have had the best success with Octura couplers. Their all steel design allows them to be tighten hard and their finger detail allows decent pinching on under size cables.
Some Octura couplers have runout issues if the fit between the motor shaft and coupler is loose, but otherwise these work great.

As Fluid pointed out, you should wipe off any grease or oil on the shaft and inside the coupler where the coupler pinches the shaft. This needs to be dry to work its best.

-Tyler

[fweasel]

I put anti-seize on all my collet threads. Good tip Jesse.

[raptormash]

I've run a lot of aeromarine collets for gas with 1/4 inch cables over the years and never had an issue until they switched from stainless to a brass insert. Several people lost cables and props from those brass inserts they loosen in one run. That's the only prop and shaft I ever lost needless to say I stick with stainless inserts.

[dasboata]

I?ve had 3 cables fall out in 2 days. I?m using 1/4? cables, Aeromaine collets for 8mm shafts.

I tighten them as tight as I can and still they manage to fall out. I silver braised one Shaft to see if that corrected it, but no-go. I don?t recall Octura collets giving me this much trouble.

Any ideas on what I did wrong?
Thanks doodes!

pull the Ferrule out see if the 3 groves are filled with shaft material clean them out with a razor knife !!!

[ray schrauwen]

H&M are also excellent couplers. They are all I use. The Chinese couplers were modeled after them but H&M uses some excellent materials in comparison. Rocket City Racing in FL. sell them in USA.

I've had TFL, or the like go way out of true after a season, others like them. I've never slipped a cable since using H&M.

[jingalls007]

Thank you guys so much! I really appreciate all of the advice and have subsequently placed a few orders based on your suggestions.

Thanks doodes!

[racerr73]

I had a similar problem and I found the motor shaft was too long and when you did up the coupler, the brass insert in the coupler was bottoming out hard against the end of the motor shaft giving a false feeling the cable was tight.
Trev

[Manns50]

Don't mean to hijack this thread.
New to the scene here and am unsure...reading all of these comments ...how tight to crank on the collet? Have a Veles 29 just replaced the cable with an OSE one and Octura collet. I cranked it down pretty snug but I was frankly afraid to go all out thinking I might damage the shaft. But reading some of these comments make me wonder if I should pull out the Hulk. Def not giving it all I got just a pretty snug tighten. I have always had a tendency to strip nuts and bolts from overtightening. Anyone care to put me in the right direction?

[fweasel]

I use full size 10mm and 9mm wrenches on collets about that size, and tighten them good and tight with reasonable pressure for the threads in question. It's the little stubby freebie wrenches that get you into trouble, they don't provide enough leverage and will usually end up rounding corners.