Help me build my new driveshaft - RC Groups
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Jun 18, 2012, 07:36 PM
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Help me build my new driveshaft

Here is the tubing I have:

The top tube is the stock stainless stuffing tube

The next stainless tube specs has the sticker below it. It's the exact same diameter of the Octora prop shaft, and the flex shaft fits inside tight enough to use this shaft as end stock or even to make replacement prop shafts. It could even be used as a straight shaft it inside the brass tube, but it creates too much friction. It probably won't be used.

The Octora .130 flexshaft is next

We then have brass tube below the flex shaft with it's sticker specs below it. It fits perfectly inside the last brass tube on the bottom and is the same diameter as the Octora prop shaft. It has a larger inner diameter than the new steel tube and will probably be used to replace my teflon liner and to beef up the main brass tube as well as help reduce wobble.

Then you have the teflon tube, which does fit perfectly inside the largest brass tube which I don't want to use (the teflon liner that is)

Here it is put together:

You think this will work?

The Octora end dry spins very freely in the large brass tube. Brass is self lubricating and although I would lubricate it with grease, the tight tolerance should minimize water migration. I am worried about metal expansion of the metal prop shaft vs the brass tube an figure you veterans can tell me if that would be an issue with heat.

The teflon liner has too much slack, but it would be perfectly straight if used inside the large brass tube. I'd rather not use it at all and just use the brass but do you think the flexshaft could rub through?

I hope it's clear enough of what I'm trying to do. Thanks for any tips.

Here's a shot of how much clearance I have:

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Jun 18, 2012, 11:46 PM
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Will you be using a stinger or a strut? I did the same once on a built and there was really too much wobble. But if its going to be a submerged prop and the rpms are not high I would say try it.
Jun 19, 2012, 05:50 AM
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Nope, just stuffing tube. It actually has less play than the stock one.
Jun 19, 2012, 08:28 AM
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I have my stickers mixed up in the photo, the last two should be flip-flopped. The 3/16" is acting as a liner for the flex inside of my 7/32" stuffing tube. The Octura stub fits snugly inside the 7/32" stuffing tube. Sorry for the confusion
Jun 19, 2012, 09:50 AM
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drive shaft

The SS is a bearcat to bend.I use 7/32 with .130 and i'd run the brass right up tp dog drive and a slight neg. bend. Keep liner in 7/32 to keep water out. Next, a gentle bend toward the the motor shaft or coupler... SS wears out fast and ran SS from m/stem to dog drive. Teflon needed to be sanded down the full lenght even to get it up the SS stuffing tube. I have a couple of foreign boats where straight shaft is soft and will change to flex which will be a piece of cake. Reason. bearings need alot of maintenance or replace. Now with brass all the way, no support is needed for exterior portion of stuffing tube. Also if you want , just stick the next size brass tube from dog drive thru trsnsom 3/4" and epoxy in, rock solid. I would put an oiler above the cable shaft and make sure it is smooth where oiler emters stuffing tube.
Last edited by Mikedown; Jun 19, 2012 at 09:56 AM. Reason: more info
Jun 19, 2012, 10:18 AM
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Thanks, I'm using all brass.

7/32 Main stuffing tube-straight with no bends like the original, which the prop shaft stub fits nice and snug in.

Shoreter 3/16 brass inside the 7/32 to shore it up and help prevent wobble.

PVC T-junction (If I can find one small enough) will be placed just fore of the stub with appropriate hole drilled through both brass shafts. I'll fix a grease fitting to the top of the T and hopefully be able to pump fresh grease in and have the old come out either end, hopefully allowing me to re-grease without complete removal of the shaft (collet loosened and shaft pulled slightly back to help propogation) just like greasing fittings on older cars.
Jun 19, 2012, 01:09 PM
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drive shaft

Good luck.
Last edited by Mikedown; Jun 19, 2012 at 01:39 PM.
Jun 19, 2012, 01:23 PM
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MassiveOverkill's Avatar

I am replacing my stuffing tube completely; the stock one is too small. I don't want to use the .130 teflon liner if I don't have to, that's what the 2nd brass tube is for, to reduce the gap so the flex shaft doesn't flap around. The tube doesn't have to be bent, the original stainless one was straight and the way this boat is set up by default, there are not could get away with a straight shaft with a flex tip. There is no stinger on this boat like its big brothers, just a stuffing tube that extends to the dog collar.

I'll take pictures with it mounted tonight, maybe it will make things clearer.
Jun 19, 2012, 05:42 PM
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Pictures as promised:

Old flex top, new Octura bottom:

New stuffing tube:

Motor End:

Jun 19, 2012, 09:56 PM
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Careful of cable whip.
Jun 19, 2012, 10:19 PM
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I'll do a quick dry-run (just blipping it for a few seconds) to see if there's much vibration. I'll know right away once the new ESC comes in.

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