Shaft slipping Out?

Binding at one location means the shaft-to-coupler misalignment (or a bent shaft) is additive to the coupler-to-coupler (engine angle) misalignment. 180 degrees away they are subtractive.

Since you have a fresh double taper shaft, you can count of the shaft and it coupler being square, so all that can result is the shaft being hard to turn no matter its location in the revolution due to coupler-to-coupler alignement (engine angular alignment)

79 and I are saying its best to check your engine aligment now with fresh parts so you don't fatigue anything.

The shaft should be as easy to turn with the coupler bolts loose, as they are when they are torqued. Anything else is unacceptable.

rotate the prop and look for a heavy drag spot while it's out of the water to verify that everthing is aligned properly.

You should be able to spin the prop and have a consistent drag for 360 degress, if there is a heavy or litle spot where the ressistant changes as you rotate it then you need to fine tune the alignment a little.

Me too

keno

Well, I'd never heard of a grub screw,always called them set screws, so being naturally inquisitive I did a search using my favorite search engine and whaddya know, a set screw and a grub screw seem to be the same thing.

Probably depends on whether you're from the USA or the rest of the world.

I'm learnin' something all the time.

keno

Hi Jim

I agree, I like your solution though.
As I said my solution was ugly but it worked.

A carbide drill bit will get through a high tensile screw or bolt.

Grub screw, is a screw that has no head, meaning it can sit below the surface.

I would have to look up the Machineries Handbook to see if it’s an acceptable term to use in the States.

Regards
Rob

Hi
I had exactly the same problem getting my prop shaft out of the coupling. Two square head grub screws

A tungsten Carbide drill bit will do the job. If you can not get a hold of one use a masonry drill bit. The end of a masonry drill has a tungsten tip. I used the bench grinder fashion the tip into something that resembles a steel cutting tip.

It is a really ugly solution, but it only cost me $5.00 for the drill bit. It sort of chips the grub screw away.

I re-used the coupling by drilling and tapping 3 new holes at 120 degrees apart.

I used socket headed grub screws, one of which now screws down to the key.

Regards
Rob McDonald

Gee Jim, that Grinder is pretty inexpensive, I wish I was a little closer to the gulf, I'd just tow the boat right over. OK, I can take a hint.

$9,000? 1969 Nautique--priceless, even sitting in the garage.

If there is, its bent.

Lake, if your shaft is straight there is no need to replace. Did you get it out? How?

A good machine shop can check it for straightness and straighten it if needed.

OK, I should have said "drive shaft."
I talked with Vince from skidim, he's concerned about the damage that's already been done to my coupler and shaft, and reusing may cause difficulties in alignment, so I'm may have to go the new drive shaft route--probably make '79 happy, I'm sure the drive shaft if original anyway, I have no idea how many hours are on it.

I'll see if I can find the receipt from the guy that cut my shaft. I found him by searching on Ebay on "Prop* Shaft"

As to how it happpened - who knows? Be happy you are smart enough to spot it. That puts you light years ahead of most of us.

A 90 Deg grinder can get that coupling off in about 2 minutes without damaging your shaft - a machine shop should have one of those.

Chuck,
"Damd ol boats".... just about enough to make a preacher cuss!

I was also in dry-dock over the weekend...my 64s got a boken strut..Hope to get her going next weekend....Good luck with your broken bolt... like they said above, dont break an extractor...NOT fun!

JIH, would it be worth trying a couple of raps on the prop end of the shaft with a block of wood and hammer to try and drive it back in the coupling a little? Maybe relieve some of the pressure on the locknuts?

We gotta hang in there Chuck! These are still some of the coolest old tugs made!

You should plan on buying a new coupler at this point anyway. I think you can buy just the half that fits on your prop side of your shaft. After the 4th when a lot of folks return you will get a lot of good comments about the coupler.

I really don't think you will have any success trying to remove those bolts. I think they are buried into the shaft sideways just enough to make things difficult. I also don't think it's frozen threads that are creating the problem. Like I said I think when the shaft moved back the ends of the screws became buried into the shaft. You make be able to drill them out if the broken end is flat enough for you to get the drill started. Use a center punch and large hammer to dink a dimple into the center of the end of the broken bolt so the drill will have a "hole" to ride in to get started.

Use a lot light oil of cutting oil on the drill bit to keep it cool while drilling.

Like someone above said, if you break the extractor off into the bolt your only path will be hack sawing.

Another appraoch: You may be able to hack saw the coupler and split it open slightly with a chisel once you saw completely through one side. This would allow you to forget about the bolts, save your shaft, and just buy a new coupler or coupler half.

Maybe Dremel has a tool that will saw through the coupler half. This might be the best path!!!!! With a Dremel you may be able to cut a wedge right out of the coupler half to let the coupler fall off. What does a good Dremel tool cost? $30.00 ?

Use PB blaster, and try the extractor set. I would by my own, becuase you may end up breaking them. If worst comes to worst, cut and replace the shaft and coupler, and use loct*te on the new set screws. This will keep them from backing out, but also prevent them from seizing in the coupler. I am not experienced enough to do the heat method, I'd rather cut and replace. I think the extractor set will do it though, especially if you drill the screws all the way down to the shaft. Get some good t*tanium bits.

Another DIY option at this point is to hack saw the shaft right behind the coupler and replace the shaft and the coupler with new.