Shortening Drive Shaft

[GordMay]

Originally Posted by a64pilot

... NAS is roughly equal to a grade 8 I think ...

Grade 8 bolts are designed for a tensile loading setup, while an NAS bolt is designed for shear loading.
NAS have a minimum tensile strength of 160,000 psi and a minimum shear strength of 95,000 psi.
Grade 8 have a minimum tensile strength of 150,000 psi and 130,000 psi in shear.

[a64pilot]

Frankly, I just replaced all four trying to tame this vibe, and aligned as close as I can get, which is awfully close.

What do you think of the yard in Lynhaven? Miller Marine I think its called. I don't like the one in PC, they acted as if they were going to do the work, but subbed everything out, were way late, poor quality and didn't do everything I was charged for.

I need a bottom job too, may as well have this shaft done. I believe they have a drive train specialist there as well

[a64pilot]

Cmon Gord, I said roughly

[HappyMdRSailor]

Originally Posted by a64pilot

If there is a key, likely it's a half moon key not a square one.

Woodruff???

[GordMay]

Originally Posted by a64pilot

Cmon Gord, I said roughly

Indeed.
Anyway, your ANS bolts would be better, in this application.

[a64pilot]

ANS?
Gotcha! First mistake I have ever seen you make, You are Human after all

[a64pilot]

Originally Posted by HappyMdRSailor

Woodruff???

At least I didn't call it a thingie

[Sailmonkey]

Originally Posted by a64pilot

At least I didn't call it a thingie

But if you had, the hodgemeister refledging tool would have sufficed to reinstall it.


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[Terra Nova]

Originally Posted by a64pilot

I need to shorten mine by about three inches, there is too much shaft sticking out behind my Cutlass and this may be contributing to a drive train vibration problem that I have had since I bought the boat.
My coupling seems to simply be slid onto the shaft and attached by means of a thru bolt going through the shaft, no keyway.
I'm thinking I can first drill though the shaft at the proper location and then with the boat in idle use a hack saw to cut mostly through the shaft, and finish cutting with motor off, slide the coupling back on and put the bolt through it securing the shaft to the coupling.

Will this work?

My other option is of course find someone and pay them.

Mickey Mouse!

When you need to haul the boat for other work, have a qualified marine oriented machine shop cut and keyway the shaft, check/correct for straightness, and replace the coupling with a properly keyed one. Through bolting creates a weak shaft. Very poor installation.

[Frankly]

"What do you think of the yard in Lynhaven? Miller Marine I think its called. I don't like the one in PC, they acted as if they were going to do the work, but subbed everything out, were way late, poor quality and didn't do everything I was charged for."


Miller Marine up in Southport has a good reputation but pricey. I have also heard that have some strange policies on "do it yourself".

Bay County Boatyard is where I usually go but I am a "do it your self", big time. Nobody touches my boats but me. In 50+ years I have hired boatyards on two different occasions. Bad results and financial rip off both times. Since haul and pressure wash is all I need from BCBY, Robert and I get along just fine. Incidentally he owns an IP35 which he keeps at St Andrews Marina.

If you go up to Miller watch out for the transmission lines across the Bay. Those things are low in the center but over 100 ft next to the towers. 110KV and an aluminum sailboat mast would not be a make your day experience.

There is another yard out at Grand Lagoon but no info on them. I think it is called Pirates Cove.

[Jim Cate]

There is another yard out at Grand Lagoon but no info on them. I think it is called Pirates Cove.

Truth in advertising??? Maybe they should hire a new PR guy...

Jim

[HappyMdRSailor]

Originally Posted by a64pilot

At least I didn't call it a thingie

TRUE dat !

Originally Posted by Sailmonkey

But if you had, the hodgemeister refledging tool would have sufficed to reinstall it.
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I had to look this up... perfect for the application...

Originally Posted by Jim Cate

Truth in advertising??? Maybe they should hire a new PR guy...

Jim

HA!!!
+1

[rwidman]

How did the shaft get to be too long in the first place? Did the builder make a mistake?


Once you've figured this out, my suggestion is to have a qualified boatyard fix the problem or if you can do this yourself, remove the shaft and take it to a machine shop that works on boat equipment.


A lot can go wrong trying to do this while the boat is in the water and especially with the engine running and the shaft turning.

[HappyMdRSailor]

Hey Mr. Pilot,

This whole in situ lathe cutting operation sounds like a whole lotta fun... But... I just thoughtta sumthn' kinda important...

You prolly wanna make sure you put the boat in fwd ???

[a64pilot]

Originally Posted by rwidman

How did the shaft get to be too long in the first place? Did the builder make a mistake?


Once you've figured this out, my suggestion is to have a qualified boatyard fix the problem or if you can do this yourself, remove the shaft and take it to a machine shop that works on boat equipment.


A lot can go wrong trying to do this while the boat is in the water and especially with the engine running and the shaft turning.

No telling, maybe shaft has been replaced? It only sticks out 2.5" so maybe a little over an inch too long, I would have thought that 2.5" would have been OK, but it's the only thing left that can be causing vibration, all else's has been checked.
I was going to cut it off and only leave .5 " and maybe one day add a globe shaft saver and isolate the shaft from the engine electrically, and maybe dampen some vibrations.


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