Shaft slipping Out?

When I replaced my prop shaft (after running the '68 onto a sand bar - ugh) the replacement shaft did not come with dimples drilled into it for the coupler set screws to seat into. I could see nothing that would hold the shaft in during a hard reverse.

I do not know the history of your boat but for what ever reason when you are reversing the thrust of the prop is pulling your shaft out.

You have to fix it or you could lose your rudder, prop, and strut.

DavidF had an experience with this.

See if you can click on thisto read more details about the subject.

I don't quite understand. The set screws are allen type screws right? Requiring an allen wrench? Did your set screws have heads on them? Hex heads? Are your set screws 180 Degs apart or 90 Deg apart?

Since your shaft has been pulled outward, the tips of the set screws are probably gaulded into the shaft.

I hate to advise people to apply heat to parts in a boat bilge because it is dangerous and you really have to know what you are doing in order to avoid a massive problem. So I will not recommend you heat the coupler to expand it. (But that is what I would do.) One trick that works well is to heat the entire part that has a broken screw in it, to very hot (a dull red color) and pour water on the screw only. The screw will contract allowing it to be extracted easily if done while the parts is still hot (a dull red kind of hot). This type of heating requires an acetylene torch to get enough heat on the part quickly. In this case, The shafts on both sides of the coupler should be wrapped in soaking wet rags to prevent the heat from transfering into the tranny and the packing seal. The entire bilge area under the coupler should be covered in fire prevention material. There must be no gas or oil fumes present.

If your set screws are allen type they will be too hard to drill I think. If they are hex head type bolts you may be able to drill them out.

If you are not savvy to all of this, or you do not have all of the required tools, at this point, you may come out ahead to tow your boat to a local shop and ask them to remove the set screws. A small machine shop might do it for you for a small charge. Maybe even find a machine shop capable of machining you a new shaft if needed and let them extract the bolts.

Thanks Jim,
The set screws are not allen; they are a square head, not hex, machine screw. They are located 180 degrees on the coupler. The heads had a small hole through them with a wire wraping around the coupler and through the bolt heads, obviously the wire wasn't needed as of late as the screws were really set up. I don't have an acetylene torch, so I'm not thinking I want to go that route.
If I try to drill and extract (without heat) and fail, am I making a tougher job for the machine shop?
If I hack the shaft off, will I be able to find a new coupler, or will I need to salvage the old one (meaning still getting the screws out).
Thanks again,
Chuck

If you break an extracter in there, its too hardened to drill out...

I say overdrill the fawkers out, use a drill-stop collet to prevent you from going too deep.

Tap the coupler setsrews to the next size, dimple the shaft with the drill so the new setscrews grab, and be done.

It its trashed anyway, go with a new double-taper shaft and coupler.

After reading all of the posts, I kinda agree with Gottaski. If you can drill the bolts out using a drill the same size as the bolt hole you should be able to pull you shaft out. USe a collet (or spacer) on the drill bit so the drill does not go deeper than the thickness of the coupler. If you don't have taps just buy a new coupler half. If you have to buy a whole coupler you may able to get the exact replacement and just don't use the half that is already on the tranny side of the shaft - use the old one that is still on the shaft.

An update, I've been drilling, drilling, driiling, using oil and t*tanium bits, starting wiht small bits and working my way up. I've got a pretty good bite with an extracter on one, but that bolt is not budging yet, worried I'll break if off. I'll try Steve's advice to knock the shaft back a bit.
I'll check with skidim to see if they carry a coupler like mine in case this one gets trashed.
Jim, in case I have to replace the shaft: do you have the name of the guy you got your shaft from?
I'm going to try once more this evening, then see if I can locate a machine shop that will give it a whirl.
I'm trying to figure out how this happend. I didn't hit anything, the stut, the prop, the rudder appear undamaged. The greatest tork in reverse is unloading off the bunks. I did start running the 540 prop late last year. Or, maybe like me, parts are just getting weak. We had a friend visiting yesterday, he thought the boat looked good in the garage.
Chuck

I chuckle everytime I read the t*tle of this post...is it just me

Chuck,
Technically its a "prop" shaft Have you had any luck getting it apart yet?

I think my 64 is back on track...got the strut and rudder on tonight!

Also glad to hear your wifes getting st*tches out next week..hope she is on the mend!!Give her our best! Gonna miss you "guys" at GL!

Nope, had to put the boat on the back burner for lots of work this week, and tyring to get my wife literally back on her feet. It will be next week before I can address it. Still cannot get the set screws out. So, I'm trying to find a machine shop. A couple of the guys I've called don't want to mess with it. I definitely want to get it out without cutting it. I'm pretty sure it's straight, but I'll check it out anyway.
Will there be any trouble sliding the shaft through the strut bearing?

The Lake wrote: Will there be any trouble sliding the shaft through the strut bearing?

Polish off any burrs you create when removing the coupler before you pull the shaft out.

I think the reason you can't find anyone interested in helping you is because it's a $50.00 job with a perceived $9000.00 downside risk. You may have to just trailer the boat into someone's parking lot and show them the problem. A sympathetic shop owner will help.

Grinder

Chuck,
After you get the Mrs "on her feet", take a "little" vacation and bring her up to NW IL...I would be glad to help you...

I believe if we put a little heat from the torch to the broken bolt area, we could get her out with an extractor.... in the mean time..keep pouring the "Blaster" to the bolt..make sure its facing up, so gravity will work with you.

Now start making those "vacation" plans

Never heard them called grub screws. Must be a down under thing.

They are made hard on purpose - so they don't deform when you tighten them into the shaft. They are harder then the shaft or the coupler and harder then most drill bits. Usually by the time you have drilled them out your drill bit has walked all around and wobbled out your original set screw holes beyond use. In fact, one trick is to drill a larger hole right along side the set screw and then use a center punch to drive the set screw out of its hole into the larger hole you just drilled along side.(I have been there a lot of times in my young mechanic days).

set screw is the term your looking for.

Yeh, isn't the world an interesting place? Differnet names for the same thing. Example: I always thought KENO was the name of a game.

Back in the water again!
Finally had time to get to it; decided to go with a new double taper shaft and we were able to test it out this evening . . . very smooth. I was worried about alignment being off, but it seems to be right on.
And, I'm not going to have to worry about a stuck coupler again (I hope).
Thanks for all the advise, once again CCFans came through for me.
I'm taking some vacation time next week, definitely wanting to get a lot of skiing in.
Chuck