Flex shafts?

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Kevin Krogness

Well-Known Member
Joined
Jun 5, 2008
Messages
2,585
Alright I went to the local hobby shop and bought bare flex shafts for a inboard... They do not have a prop shaft on them... I figure put this here since it deals with the prop and final driveline.... So my questions are...

1. What technique do you use to solder into a prop shaft/part prop and drive dog go on?

2. Do you solder then cut to size were the shaft goes into the collet?

3. Did I screw up and should have just got premade shafts?

Thankyou, Kevin....
 
First I would get premade shafts.

Second you will need a dremel tool with a grinding stone to grind a flat spot on the stub shaft for your drive dog set screw. Once you have that done install the drive dog and tighten set screw, be sure to leave plenty of room for your prop and prop nut with threads out past the nut. Install the flexshaft into your stuffing tube and into the motor collet until it bottoms out inside the collet. Pull back slightly 1/16 inch or so, on the strut end your drive dog sould end up the with a gap the same as the flexshaft size away from the strut to allow for windup (3/16 for 3/16, 1/4 for 1/4 shaft sizes. Allowing for your gap measure from the back of strut to the drive dog and this will be how much you need to cut off. So if you measure a 1/4 shaft from the back of strut to front of the drive dog and its 2 inches cut off 1/3/4" from the motor end of the shaft. Use the dremmel with a fiberglass cutting wheel to cut the shaft.
 
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its also important to use silver solder,,it holds the best...the more silver the better the adhesion...the prop shaft i.d and the end of the flex should be as clean as possible...some flux also... be careful not to let the solder wick up the flex or you could end up with cable whip and breakage...

hope this helps...

alden
 
has anyone tried or used brass brazing rods to join the cable & shaft? seems it would be a stronger bond & less likely to wick up the flex. you would need at least a small hobby/jewelers torch. any thoughts?

kevin, i agree with tim & ron, just buy a premade one ;)
 
My own shafts is what I mainly use, but ill agree 100% with tim

It takes a lot of practice to connect cable to shaft, not to mention having cable and shafts to practice with.Tim
Lots of tricks to making them and I still find little things that make it better, like how you apply flux can make a big difference in the way things go together ;)

IF anyone needs a little advice or help doing it feel free to call me

http://www.aircapitolhobbies.com/Contact.html
 
When you solder the cable to the stub shaft you have to keep it perfectly straight. I use a small lathe.

Al Hobbs
 
when I first started making them I used the lathe, then made a wooden jig<<sucked wood heat and flux dont last long lol when I got my mill I machined a jig that will do 2 of each (1/8 3/16 1/4 from 125-1/4 cable) not practical unless your making a lot of shafts.

Brings up another good point as to why the loctite method is not practical, when you use the loctite method it will hold your stub to the shaft, I wont ever argue that---BUT once you put it together and let it cure that's it there is no adjusting your fit or truing up the cable in any way-- with soldering if its not running how you like you can move it quick and easy with a little heat.. only bonus to loctite is there is not much skill or know how needed to join the two parts, it kind of makes ya think---would I "glue" a drive-shaft on a car or truck or any other major drive-line part? OK if you would here is the part number you need loctite 603 lol :p
 
I was never successful in hard silver soldering a stub shaft to a cable. I was able to make a reasonably clean job joining the two but the problem is that I annealed both the cable and the shaft in the process.

It is quite easy to silver solder (StayBrite) the stub shaft with a soldering iron. The low temperature does not change the temper of the steel but I don't trust the join to actually use it in a boat.

It is not worth the trouble so I just buy the shaft ready made.
 
Soldering is a waste of time for most boaters who cannot solder worth a hoot. All that will happen is they will lose the stub shaft and their prop. I use Hughey shafts almost exclusively. OTOH I and others have had success using bearing retaining compound to attach the cable to the shaft. Locktite and Permatex are two brands which are effective. I was dubious at first but after seeing it hold on many boats I have tried it.....so far so good.

.
 
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Big difference between sweating in or locktighting a piece of flex in a hollow shaft or ferrule an brazing flex to a hardened shaft and keeping it true and final grinding back to .250 is a bit more difficult.
 
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Kevin,

It really doesn't matter who/where you get them, as long as they're Hughey shafts, you are good to go. The one thing I can say about getting them straight from Hughey is that he will cut them to length and solder the end for about an additional $6-8, and I can tell you there is nobody who can solder the end better than Ed Hughey.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros
 
IMG_3836 (2).jpg

I do this to my collet ends of the flex, 45% high temp silver solder, it cured the slipping problem for me.The soft solder tends to compress over time and lets the collet loosen up.
 
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