Stern gland bolt sheared.....aaaargh!

[Barry]

I re-packed Lemontoes' Tonka's stern gland at the weekend.

 

Incidentally I found no packing in there when I removed the stern gland follower - there's no wonder it was using a load of grease is there!

 

Unfortunately I sheared one of the stern gland bolts

 

 

Obviously I need to resolve this swiftish so assessment by stages says: -

 

There's no water coming in despite only one bolt in position.

 

Having run the engine in gear briefly a good listen and feel shows that, despite the gland follower being slightly off square, it seems to be nice and quiet and running smoothly - no sense of it binding at all.

 

Tonka is away from its home mooring this week but needs to travel a few miles on the first weekend in December so if the worst comes to the worst I think we might be able to move the boat under its own steam providing we keep a close eye on the stern gland.

 

Brian from Alton has had a look and suggested a G clamp in place of the missing bolt might well square the gland follower up as a short term fix. I quite like this idea.

 

 

 

This is the broken bolt that I have to replace

 

 

I think its phospher bronze.

 

Diameter using digital callipers is 0.391in or 9.94mm.

 

17 tpi gives a pitch of 1.49 by my calculations.

 

I don't have a thread guide but I do have a copy of the old Zeus data charts and reference tables.

 

Going for the obvious in the Zeus book 10mm metric course thread is very close at 10mm dia (obviously) and pitch of 1.5mm.

 

The outside diameter doesn't match closely for Whitworth, UNF or UNC

 

Hold on I've got an idea.........

 

I'm back - Rootling about in my come in handy store I have found a 75mm length of steel stud (probably 10mm since its not very old) and the nuts off the phospher bronze stud run down it beautifully with no slackness or binding so it appears to be M10 and I have a replacement stud to hand that just needs cutting to length - though it is steel and not phospher bronze.

 

 

 

I'm looking now at getting the old stud out. It broke off just level with the face of the stern gland.

 

 

 

My first thought was that this is a drydock job if I want proper access to drill the broken stud out of the gland because then I can break that shaft coupling which would allow me to slide the prop and shaft out of the boat and remove the gland follower. However Tonka isn't due for blacking till next year and dry-docking now to solve this problem ASAP will cost a lot of money so I'm looking at an alternative approach to repair this in the water.

 

Space is limited in there as you can see but I'm thinking about

 

1) undoing the other bolt and dropping the gland follower back to the coupling

 

2) since the stud sheared nice and square I think I can get in with a centre punch to start a hole for a stud extractor.

 

3) I have a Bosch Ixo electric screwdriver with a cranked head and a small chuck attachment so here's the first question that needs your experience.....do you think that since this is phospher bronze, and hopefully softer than steel, it is feasible to go in with a pilot drill at screwdriver speed and then keep going in with slightly bigger drills to stud extractor size?

 

4) Alternatively I think I can buy a right angled chuck attacment for my cordless drill - the problem with that is the closeness of the shaft so I might not be able to drill down the centre of the broken stud dead square. However I'm thinking that a stud extractor might still work provided the hole I drill is not at too much of an angle.

 

5) Alternatively again and thinking bigger - do you think it is feasible to break that coupling, go in the weedhatch and pull the prop and shaft back into the gland so I can get a drill straight and square down the broken stud with the best room I can get with the boat in the water?

 

 

Your experience and advice will be gratefully received

 

 

PS - Where do I buy M10 phospher bronze studs from? I'm thinking about putting a steel one in temporarily but when the boat goes in for blacking next year I'd like to do a proper job and put two new phospher bronze studs in

Edited November 26, 2014 by Bazza2

[RLWP]

See if it will undo first using a punch or sharp chisel. Get the corner of the chisel to dig into the stud somewhere off centre and give it a tap. Sometimes you can get these to start undoing. Once there is enough thread showing, use pliers/molegrips/fingers

 

Richard

[magnetman]

I think stainless would be ok and less likely to shear as well

 

not too sure about getting the old one out but if you can get a drill on it maybe try a left hand drill bit and see if it pulls it out ?

Might work. I've never tried it but I think it could be a way to do it but all depends on drill access. Maybe its worth looking at hiring and angle drill as they can work in pretty confined spaces.

[John V]

If you can get the pilot hole in it ....what about a stud extractor....carefully!!!....(you have to be damn careful not to snap one 'cos otherwise you are in really deep doodoo)

[MtB]

Usually the threaded hole containing the broken off stub of the stud passes right through the flange. Engaging a drill bit in the face of the stub in the hole will probably result in it turning clockwise and unscrewing itself out through the back of the flange.

 

You might need to take the drive coupling off to get space to get a cordless drill in. Richard's method is best to try first though.

 

MtB

[Guest]

Just a thought, but one of those flexible drives for an electric drill might let you access the problem stud, especially if you grind a very short drill bit. A decent (short!) Dormer or similar quality drill should get a pilot hole in.

[bizzard]

More often than not those studs are an easy and usually slack screw fit in the flange and are very often finger tight and unscrew very easily (plenty of grease about) A little bit of gentle teasing with hammer and punch should undo it enough to get a finger grip on it and unscrew it.

There are available small right angled 90 deg drill gearbox attachments. Aldi were selling them a while ago for about £9.

[Barry]

See if it will undo first using a punch or sharp chisel. Get the corner of the chisel to dig into the stud somewhere off centre and give it a tap. Sometimes you can get these to start undoing. Once there is enough thread showing, use pliers/molegrips/fingers

 

Richard

 

 

I thought about that because I do have a tiny chisel with a cutting edge of about 5mm - But I worried about buggering up the nice flat face of the bolt so that I can't get a hole drilled in it in case tapping it round didn't work.

 

 

 

 

Usually the threaded hole containing the broken off stub of the stud passes right through the flange. Engaging a drill bit in the face of the stub in the hole will probably result in it turning clockwise and unscrewing itself out through the back of the flange.

 

You might need to take the drive coupling off to get space to get a cordless drill in. Richard's method is best to try first though.

 

MtB

 

There's a thought MtB - that would be to my advantage.

 

 

 

 

Just a thought, but one of those flexible drives for an electric drill might let you access the problem stud, especially if you grind a very short drill bit. A decent (short!) Dormer or similar quality drill should get a pilot hole in.

 

About to do some internet shopping - though now I think about it I do have a flexible drive for an electric screwdriver that will take the hexagonal end of my tiny chuck. I wonder if that might do the job

 

 

 

 

More often than not those studs are an easy and usually slack screw fit in the flange and are very often finger tight and unscrew very easily (plenty of grease about) A little bit of gentle teasing with hammer and punch should undo it enough to get a finger grip on it and unscrew it.

There are available small right angled 90 deg drill gearbox attachments. Aldi were selling them a while ago for about £9.

 

That's reassuring Bizz

 

THAT'S where I saw one - I knew I had

Edited November 26, 2014 by Bazza2

[MtB]

There is a risk of over-complicating this. As Bizz points out the stub is just sitting loose and baggy in the threaded hole. it just needs half a turn or a whole turn in probably either direction to get a bit of it showing then unscrew it with yer fingers.

 

Try fiddling it round a bit with the tip of a screwdriver. You may even get it to turn with thumb and forefinger place back and front of the hole, and squeezing and rotating.

 

MtB

[magnetman]

BS edit

Edited November 26, 2014 by magnetman

[Kwacker]

Do I espy a soggy doughnut just to the left of the gland?

[ditchcrawler]

Why cant you break the coupling and slide the prop shaft back with the rudder hard over until the end is near the face of the stuffing box. then you will have room to get a drill in.

[Barry]

There is a risk of over-complicating this. As Bizz points out the stub is just sitting loose and baggy in the threaded hole. it just needs half a turn or a whole turn in probably either direction to get a bit of it showing then unscrew it with yer fingers.

 

Try fiddling it round a bit with the tip of a screwdriver. You may even get it to turn with thumb and forefinger place back and front of the hole, and squeezing and rotating.

 

MtB

 

Its a good thought MtB

 

I might just buy a right angled drill attachment and a set of stud extractors to have in for the future if your suggestion works. If your suggestion doesn't work then I've got the tools I need to hand

 

 

 

 

Do I espy a soggy doughnut just to the left of the gland?

 

No - its a very soggy greasy doughnut of baler twine. Comes in handy don't you know

 

 

 

 

Why cant you break the coupling and slide the prop shaft back with the rudder hard over until the end is near the face of the stuffing box. then you will have room to get a drill in.

 

See point 5 in my OP

Edited November 26, 2014 by Bazza2

[RLWP]

Do I detect a man keen to buy some new tools?

 

Get your chisel out and stop messing

 

Richard

[nb Innisfree]

Do I detect a man keen to buy some new tools?

 

Get your chisel out and stop messing

 

Richard

A man must have new tools.

[Barry]

Hehehe...... I luuuurve new tools. Its such a pleasant surprise when something you bought a while ago turns out to be exactly what you need

Do I detect a man keen to buy some new tools?

 

Get your chisel out and stop messing

 

Richard

 

You do

 

Trouble is I'm not there at the minute - I'm here - and I'm trying to have a workable plan for when I'm there

[sultan derocco]

If you take out the other stud, then rotate the gland through 90 degrees so that the broken stud is at the top,you will have more room to get at the offending part and perhaps get a sensible drill at it.

The greaser tube may be in the way but it is flexi so should tuck out of the way.

The fact that it has sheared suggests to me that the the broken part may not be finger tight!

Good luck

Sultan

[Neil2]

Am I being thick here... if that remaining bit of stud isn't really tight how did the stud shear in the first place?

 

If the stud won't shift without proper access to it as a temporary fix you could modify a suitably sized G clamp to put the threaded part through the hole in the gland follower, with a captive nut on the thread this would keep the clamp square and secure as you tighten it does that make sense? Maybe that's what your mate had in mind.

 

 

PS didn't see Sultan's post, obviously thinking the same thing at the same time.

Edited November 26, 2014 by Neil2

[RLWP]

Am I being thick here... if that remaining bit of stud isn't really tight how did the stud shear in the first place?

 

By being in tension

 

Richard

[Barry]

If you take out the other stud, then rotate the gland through 90 degrees so that the broken stud is at the top,you will have more room to get at the offending part and perhaps get a sensible drill at it.

The greaser tube may be in the way but it is flexi so should tuck out of the way.

The fact that it has sheared suggests to me that the the broken part may not be finger tight!

Good luck

Sultan

 

Yep - I've been thinking about that. I was able to remove the follower to get the new gland packing in without the canal coming in so I'm confidant I can do it again now it has packing in as well

Am I being thick here... if that remaining bit of stud isn't really tight how did the stud shear in the first place?

 

If the stud won't shift without proper access to it as a temporary fix you could modify a suitably sized G clamp to put the threaded part through the hole in the gland follower, with a captive nut on the thread this would keep the clamp square and secure as you tighten it does that make sense? Maybe that's what your mate had in mind.

 

 

PS didn't see Sultan's post, obviously thinking the same thing at the same time.

 

As Richard says. I was too heavy handed putting the second turn of packing in and trying to squash it up enough to get a third.

 

I've looked out a couple of small but hefty G clamps - one of them is about the right size to do as you suggest. I particularly like the idea of the captive nut on the G clamp thread. I shall have to grind off the flexible flat head it has on now and look for a nut.

[Brin Morris]

A G clamp would work fine to move the boat. I do have some stud extractors that do not need a pilot hole, they drill in anti clockwise and grip the stud, work ok if stud not too tight. I could drop them off if you need them. If you need a clamp I have several sizes that would fit. Do know someone who was in same situaton and used a clamp left it on for over a year with no problems .

[Barry]

A G clamp would work fine to move the boat. I do have some stud extractors that do not need a pilot hole, they drill in anti clockwise and grip the stud, work ok if stud not too tight. I could drop them off if you need them. If you need a clamp I have several sizes that would fit. Do know someone who was in same situaton and used a clamp left it on for over a year with no problems .

 

Ah! Just twigged who you are and that you know exactly where Tonka is. We spoke the other day didn't we. That's a very kind offer sir.

 

I just saw some of those stud extractors you refer to, on the toolstation website. Not a lot of money either

[Neil2]

 

By being in tension

 

Richard

On a stern gland, - really? I wouldn't have though the forces were strong enough to shear a big stud like that. (I'm not being argumentative just trying to understand)

 

I assumed that when Barry was tightening the pusher he turned the stud itself rather than the nut(s). The picture of the sheared stud sort of suggested that.

 

Edit - sorry Barry i seem to be a few minutes behind everyone this afternoon, just seen your explanation.

 

Anyway I now know why some folk have one of those glands with the pusher that's like just one big nut...

Edited November 26, 2014 by Neil2

[nb Innisfree]

I can't see why ordinary ss nuts and bolts cant be used instead of studs, drill threads out and bolts slot straight through and always easily removable, granted it's bit more fiddly to adjust but far simpler and less hassle in the long term.

[bizzard]

As I mentioned earlier Bazza that bit of stud is probably loose in the thread.and even something like a little bolt or that bit of broken off stud stuck back onto its other bit with a spot of Araldite or super glue would very likely be strong enough to unscrew the bit of stud by hand. But of course the two mating surfaces will need to be scrupulously cleaned first with white spirit or similar.