Square drive systems

[Bob Morton]

Hi Bob.

I found that the ball washer detierate. I use two Teflon washers in front of the strut and in the rear. . Drill a small hole in the strut so you can grease thru out day. Works for me.

The other Bob

 

[Dasboatman]

Hey Brother Bobs,

Yep, looks like we have the name surrounded.

I agree with Bob M. - Teflon washer between drive dog and strut only for me. small hole in side centered between roller bearings in strut, and greased each run using that pinpoint grease gun shown on page 1 this thread.

I found that the ball bearing thrust washers with hardened washers on either side deteriorated quickly, and the washers cut into the stub shaft.

For years I used Dumas Heat Treated Armco 17-4PH Stainless steel driveshafts (H-24, 3/16" X24" for Drag n Fly 60) but I have heard that Dumas no longer heat treats their shafts.

I ordered a couple 3/16 * X 25" Hard shafts from Gary Jensen - Metal Concepts, Inc. that are very hard but not threaded, so just use a wheel collar to hold prop on.

CHEERS !!! Bob

 

[dwilfong]

If you use the lead Teflon bushings thy will not wear out the stub shaft. also you don't need to lube them. have bin using them in my Octura ss strut for a few years on my 1.01 SGX and have never changed them. thy also are smooth as glass.

 

[dave roach]

Marty put me on to the square drive system 20 years ago on the 21 and I have never looked back..You aren't pushing on the bearing and they last a little longer.

Dave Roach

 

[BobBonahoom]

Very helpful. I am going to try both needle bearings with a hardened shaft and a soft shaft with lead teflon bushings and see which works best. I will use a simple teflon thrust washer set up. Matson's seemed to have the parts I needed.

 

[John Beardslee]

Hi Bob,

I used a hardened shaft with the lead Teflon bearings with no problem for years.

Thanks, John

 

[John Beardslee]

Hi Bob Johnson,

I forgot to mention that after we couldn't get the 17-4 PH shafts hardened we had 440C Stainless shafts made up by Boston Shafting. They were ground after heat treating so were straight and with no threads, I cut small grooves in the tail of the shaft with a dremel and cutoff wheel and used double wall shrink tubing to hold the prop on. I never felt I could trust the wheel collars.

Thanks, John

 

[dwilfong]

The main trick with the lead Teflon bushings is to make a insert tool. If you just use a punch it will mushroom the end and it will feel tight.

Also get some 1/4 round and use this to size the bushing after insertion. The round stock is just a tad larger than a polished shaft.

This will give you gust the right feel when turning the shaft. You will know when it is right.

The lead is soft so take care putting it in the strut.

 

[BobBonahoom]

John,

That is good info. This might be a source of hardened and threaded stub shafts with threads: http://www.rocketcityracing.com/aeromarine-1-4-in-stub-shaft-hardened-and-threaded-x-4-in/

David, what does your insert took look like?

 

[Ian Inverarity]

]Guys,

I am setting up my first square drive on a 101 hydro using a hardened steel stub shaft running in needle bearings. My question is, what is best to use for thrust washers? I have some ball race bearings and I also have what looks like a moly impregnated plastic (teflon?) washer with two steel washers. See pics. What do you find works the best on bigger boats?

Bob,

I use these grooved washer ball thrust bearings with hardened shafts and needle rollers:

http://www.smallparts.com.au/store/item/t00700130gbr/bearingsthrustballgroovedracetype/

These last me a very long time, I have been using them on various boats for more than 12 years, I can only recall wearing out 2.

 

[BobBonahoom]

Hi Bob Johnson,

I forgot to mention that after we couldn't get the 17-4 PH shafts hardened we had 440C Stainless shafts made up by Boston Shafting. They were ground after heat treating so were straight and with no threads, I cut small grooves in the tail of the shaft with a dremel and cutoff wheel and used double wall shrink tubing to hold the prop on. I never felt I could trust the wheel collars.

Thanks, John

Hi John,

Been a long time since I used to run into you at Belle Isle! We were young then.

I was able to get some hardened Octura prop shafts. I am interested in the heat shrink idea you used. How deep were the grooves you cut? Do you have any specs or a source for the "double walled shrink tube"? I am not familiar with that. How thick is it, etc.?

Thanks

PS - this stuff (the heavy duty one) looks like it might be good because it is thick wall (.090"). http://www.mcmaster.com/#heat-shrink-tubing/=rheqt3

 

[John Beardslee]

Hi Bob,

Sorry for not seeing this sooner. Yup, spent a lot of time at Belle Isle. The grooves I put in the hardened shafts both 3/16 & 1/4 were about .010 - .015 deep and I put 4 equally spaced ringed grooves using a dremel cutoff wheel. I chucked the shafts in a lathe and spun them while hand holding the dremel the grooves were about 1/8 apart. I used a plastic washer between the prop and the shrink tube. I bought the double wall from a company called Sinclar Rush that I used to buy the red caps for our Bru-Line antenna that we manufactured. If you do a search on the internet for shrink tubing you'll find single, double and thriple wall. The heavy stuff you mentioned is way to thick a side wall compared to anything I used. I noticed some available that has an adhesive on the inside which sounds good. I can't seem to find any reduced hex 1/4-28 lock nuts for my twin so I may go the shrink tube with the adhesive route.

Thanks, John