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flex shaft

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Old 04-09-2008, 02:41 AM
  #1
gasmanjc
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Default flex shaft

hi all, i am building a boat from scratch using a 31cc engine. could any one help me with info on how to make a flex shaft as i keep breaking solid ones. i have tried myself and failed about 4 times as the outside of it shears off in a matter of seconds,i always make sure it is the right way round . the ends of the shaft are to fit into a square opening. any help is greatly appreciated thanks.
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Old 04-09-2008, 03:34 AM
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Default RE: flex shaft

go look at cc racing site. Hughey cables.
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Old 04-09-2008, 04:11 AM
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Default RE: flex shaft

Go to the mower shop and get a 1/4 flex cable,the square end fits in the slot the other end needs soldering to a ferrule this then attaches to a solid stainless steel shaft via 2 grub screws.If you hate soldering you can also use loctite retaining compound 603 to glue the ferrule to the flex just make sure you clean the flex well beforehand.You need a 5/16 int diam brass tube for the flex to run in and use grease for lubrication hope this helps.
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Old 04-09-2008, 04:41 AM
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Default RE: flex shaft

Be sure everything lines up and nothing is binding..
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Old 04-09-2008, 05:15 AM
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Default RE: flex shaft

thanks martino1fan,i do have the original cable that came with the engine with the square end that slots in so im half way there.
so the ferrule slots over the other end of the shaft which im guessing i leave as the original round shape. does the stainless shaft you speak of have the same square end as my flex or is it suited for the prop, i am trying to have both the ends square
(excuse my limited knoweledge i am new at these type of boats)

thanks knahinu i will keep that in mind.
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Old 04-09-2008, 05:26 AM
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Default RE: flex shaft

hi mate the other end of tha cable should be round although you can get square too but lets asume its round yes it slots into the ferrule then attaches to a round stainles shaft this rides in the strut asuming its surface drive? then after the strut you have a thrust washer then a 1/4 gap and then a drive dog that ataches via a grub screw which tightens onto a flat spot you file on the shaft then your prop goes onto the dog and then your prop nut and thats it.you say you want both ends square i asume you mean the flex? i believe you can get those too but a lot depends on lengths needed i supose i dunno.In my opinion id go with the round end where the prop shaft goes makes life simpler.a few pics of your setup would be good ,what drive are you using,strut stinger or other?.heres a pic of my old woody with the ferrule setup ,i now use a ready welded flex and shaft on my other boat,you can also buy those with a square end for the motor end,saves messing with solder etc but you will need to be carefull getting the correct length for the job as you wouldnt be able to cut much off with the square ends both ends.
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Old 04-09-2008, 05:39 AM
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Default RE: flex shaft

by the way try here for your gear my mate reckons theyre a good source hes from Perth.
[link]http://www.rcjets.com.au/rcjets_catalog/index.php[/link]
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Old 04-09-2008, 05:42 AM
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Default RE: flex shaft

ok heres some pics this is not the exact same set up as this is from my old boat , but is very similar
this is what i want the shaft to look like but made from flex cable and without the thread in the middle.

this is the set up it is goin into

hope this makes it a little clearer
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Old 04-09-2008, 05:44 AM
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Default RE: flex shaft

why? whats the other end going into? what drive etc.my advice is buy a nice strut setup and go with that.how about something like this one ?.even has a rudder offset to the right
[link]http://cgi.ebay.co.uk/aluminum-strut-rudder-with-roller-bearing-silver_W0QQitemZ300213680609QQihZ020QQcategoryZ340 58QQcmdZViewItemQQ_trksidZp1742.m153.l1262[/link]
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Old 04-09-2008, 05:59 AM
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Default RE: flex shaft

it is going on an airboat, i am using a setup that uses most of the original parts from the brushcutter that the engine was sourced from. no one running airboats uses this method. both ends of the flex are to be the same size, im not exactly sure what size the ends are.
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Old 04-09-2008, 06:03 AM
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Default RE: flex shaft

maybe you should post this on the airboat forum then
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Old 04-09-2008, 06:04 AM
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gasmanjc
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Default RE: flex shaft

heres the boat
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Old 04-09-2008, 06:05 AM
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Default RE: flex shaft

like i said no one uses flex shafts on airboats so i thought this forum might get me the answers i need
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Old 04-10-2008, 05:32 PM
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STEVE MARSHALL
 
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Default RE: flex shaft

Hi Ggasmanjc, try finding a place that fixes speedos and makes the speedo cables, in Perth thers a place called flexi drive,
Steve
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Old 04-11-2008, 01:35 AM
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thanks steve marshall i will check it out, i never would have thought of that!
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Old 04-11-2008, 07:32 AM
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Default RE: flex shaft

looking at the picture, what is supporting the propeller shaft near the propeller? that might be why you keep breaking things.
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Old 04-11-2008, 10:20 AM
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Default RE: flex shaft

give warehouse hobbies a call tony might be able to fix you up as they make their shafts in-house
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Old 04-11-2008, 07:32 PM
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Default RE: flex shaft


Quote:
ORIGINAL: Wet-N-Wild

looking at the picture, what is supporting the propeller shaft near the propeller? that might be why you keep breaking things.
the reason i keep breaking things is i run into solid objects like light posts and such when im dry running
. the solid shafts i make arent quite true, so any extra stress on the part seems to weakin it and eventually break it.
a flex shaft would have a bit more give than a solid shaft and a lesser chance of breaking.
as for support, i can pick the boat up from the shaft and it doesnt budge,thats 7 kg of weight.
thanks for the info guys keep it comin!
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