Square Drive Collets

[Elias Vazquez]

how is it working out?

Only been out half dozen times or so with this new set up, so far love it.

 

[Eric Bourlet]

Brad, can you post more details on the keeper? Is there an O ring between the keeper and the stuffing box?

 

[Hydro Junkie]

Elias

I am currently setting up a 21 Road Runner with square drive. I absolutely see the benefit of it not putting presure on the engine and also transferring force of the prop on the strut. When I look at your setup the question I have is how do you relieve the pressure of the prop to shaft to engine?

James,

It is a very simple set up, square nut at the motor, conventional cable with the motor end squared, keeper so that the shaft doesn't slide out the back, bumper for the keeper on the shaft tube, teflon thrust washer between rear of strut and drive dog. Beauty of this set up is as Brad brought up the entire assembly is oiled, which is what I was after along with not thrusting on the motor bearings but on the strut instead., I'm using the Woods oiler .

James,

To expand a bit on Elias' post, the thrust from the prop is pushing on the strut, there shouldn't be any pressure on the engine. You have to remember that the cable will shorten slightly while under load so, in theory anyway, there shouldn't be any axial pressure on the engine

 

[Brad Christy]

Eric,

The keeper would be a steel "disk" made up of two half disks, screwed together with opposing screws for balance. I would probably start with two square plates for the purpose of machining, stating with the tapped and counterbored holes. Then assemble the two halves and drill and bore the through hole for the shaft. Disassemble and machine about .005"-.010" from the mating surfaces to allow for clamping on the shaft. Finally, would clamp the keeper on a pin in a collet on a lathe and turn the OD.

It sounds like a lot of work, but it would probably not take very long.

My shaft oiler looks like a split collar, uses a length of large fuel line as a "reservoir" and clamps the inner shaft tube and stuffing tube together. I would just make it so that it protruded past the end of the shaft tube just enough to keep the keeper from contacting the shaft tube. Not a big deal, really. The only time the keeper would contact anything is during throttle-down.

Elias,

I'm not knocking your set-up at all. Steve does beautiful work and has some clever design thoughts. There are lots of way of getting there from here, and no two people are going to take the same path.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

Model Machine And Precision LLC

 

[Brad Christy]

Eric,

Here is the basic idea. Easy Peasy.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

Model Machine And Precision LLC

Keeper Collar.pdf

 

[Eric Bourlet]

Thanks, I get the keeper in the photo there is something black between it and the oiler.

 

[dave roach]

Eric

It looks like a oring to me.

 

[shoboat]

Brad,

That is the set up I am going to try this year on the 21 Hydro.

Looks Nice,

Mark Sholund