Boring studs out of a cast iron keel

[mog]

Does anyone have any contacts or a business that can bore out four x 1"BSW studs from an iron keel? The keel weighs about 560kg and the studs are cast in J shaped so cannot be unscrewd.I am looking to get them bored out and new threaded holes cut to replace with new studs approx 300mm deep. Oversize up to about M30 would be acceptable.
Any suggestions or advice from the learned engineers out there will be appreciated.
Thanks. Meteor

 

[NickRobinson]

Boring studs out of a cast iron keel ........

Make them read 'Hansard'?

(Apologies- couldn't resist!)

N

 

[mog]

or they could come round to yours for an evening.

or they could come round to yours for an evening


QUOTE=NickRobinson;4636971]Boring studs out of a cast iron keel ........

Make them read 'Hansard'?

(Apologies- couldn't resist!)

N[/QUOTE]

 

[sailvayu]

I would rent a mag drill and do them in place. Not hard and a lot easier than moving the keel. I did this awhile back on a Contest 25 I owned.

 

[mog]

mag drill

I would rent a mag drill and do them in place. Not hard and a lot easier than moving the keel. I did this awhile back on a Contest 25 I owned.

Thanks Capn. I have considered this but it is a deep fin keel and i will need to lift the grp hull off to use a mag drill and the surface is a curved shoe that is not conducive to a diy effort to find centres and drill deep and straight. also I have no way to tap new threads of that size.
MOG

 

[theoldsalt]

I suggest you either cut off or ignore the old studs and just drill for new studs a little distance from the old ones. Trying to drill out the old studs just seems a lot of unnecessary work.

 

[mog]

a

I suggest you either cut off or ignore the old studs and just drill for new studs a little distance from the old ones. Trying to drill out the old studs just seems a lot of unnecessary work.

I have also considered this option except that the mountings and holes in the hull cannot be moved and moving the centre of gravity by locating the new studs either forward or back isnt an option either. reinforcing the hull between the current studoos to accomodate new mounting holes for studs would be an enormous amount of work

 

[mog]

Further thoughts

Perhaps something like a large horizontal boring machine that can accomodate the keel on its side?
The sort of kit that used to be in every steam railway workshop or shipyard. MOG

 

[coopec]

Perhaps something like a large horizontal boring machine that can accomodate the keel on its side?
The sort of kit that used to be in every steam railway workshop or shipyard. MOG

They are used a lot in the mining industry today. Of course there are a lot of types

 

[Rigger Mortice]

Could you make a jig from a hefty piece of plate which fixes to the existing studs inside the boat? Then use a mag drill. Drill each stud, fit the new one, bolt it up and move onto the next stud. That way the jig is always fixed by three of the four studs.
I don't know if you can get a drill which would have a big enough throw.

 

[mog]

jig n drill

Could you make a jig from a hefty piece of plate which fixes to the existing studs inside the boat? Then use a mag drill. Drill each stud, fit the new one, bolt it up and move onto the next stud. That way the jig is always fixed by three of the four studs.
I don't know if you can get a drill which would have a big enough throw.

Yep, if I was going down the DIY route this is how I would have done it but as the boat is out of the water and lifted off the keel it would be a whole lot easier. As you say finding the long throw boring drill to hire has been a mission impossible and then I am not sure I can set up the jig accurately enough to get the holes straight and parrallel. I would still be left with the problem of cutting a M30 metric coarse thread and making the studs! I am a sailor so precision heavy engineering isnt really my best skill.
This why I have concluded that I need professional engineers to do the job but it has proved very hard to find a firm capable and willing to take on such a small (for them) job, hence my appeal for info on this forum.
I also figure that I am not be the only person out here with a 1970s cast iron keel and apple core shaped cast in studs as there were many made this way back in the day and it would be a shame to scrap the boat for want of a simple (for those with the machines and skills) repair. I hope that this thread will help others who have got the same issues in future.
Thanks for your thoughts. Meteor

 

[vyv_cox]

This may not be a cheap option but would certainly give you a top job. When working in various petrochemicals positions I have used a company called Furmanite http://www.furmanite.co.uk/ for in-situ machining on, for example, wellhead Xmas trees, large compressor crankshafts, etc. Worth talking to them at they are very capable. When I have used them their rates were not too outrageous.

 

[Appleyard]

You haven't said why you want to replace the studs..presumably it is because they are corroded? Depending on how bad the corrosion is, can you clean them up and rethread them using a suitable die and then re use them, with new nuts and washers. THEN drill additional holes at appropriate places and double up the number of studs,using high tensile steel could let you use a smaller diameter stud with better tensile strength.

 

[aitchem]

My instinct would be to tack weld a 1" inside dia tube outside the stud, say a foot long.
This would be a guide for your 1" drill.
Big drills can be hired, I used one (1100Watts) for drilling holes into reinforced concrete.
If you drilled slowly, lots of cutting fluid, it could be done.
You could always add tubes in tubes to start with a pilot hole.

 

[mog]

Why

You haven't said why you want to replace the studs..presumably it is because they are corroded? Depending on how bad the corrosion is, can you clean them up and rethread them using a suitable die and then re use them, with new nuts and washers. THEN drill additional holes at appropriate places and double up the number of studs,using high tensile steel could let you use a smaller diameter stud with better tensile strength.

Yep, the studs have severely corroded in the void between the hull and the top of the keel. This is probably due to bilgewater seeping down the threads from within as much as it has through the hull/keel shoe joint. They are now apple core shaped although good above and below it is essential to replace them.
In the scenario above I would still be left looking for a way to deep bore the new holes and thread them satisfactorily. For me it would need professional assistance and this is why I think my path of least resistance to the best result is by boring out and replacing the studs with slightly larger on the same centres.
Good thought though, thanks.
MOG

 

[mog]

My instinct would be to tack weld a 1" inside dia tube outside the stud, say a foot long.
This would be a guide for your 1" drill.
Big drills can be hired, I used one (1100Watts) for drilling holes into reinforced concrete.
If you drilled slowly, lots of cutting fluid, it could be done.
You could always add tubes in tubes to start with a pilot hole.

Another ingenious suggestion if I were able to overcome the other issues with a DIY route. I still have no way of cutting the threads and thats assuming my welding (mediocre at best) with tubes and cast iron would be accurate enough to provide a reliable guide.
Thanks for your thoughts
MOG

 

[mog]

Thanks VYV.
I will contact them and publish the results on this thread.
I am also in contact with another firm from Coventry who offer similar services to shipping industry and will post the results here for all to read.
MOG

 

[mog]

update

This may not be a cheap option but would certainly give you a top job. When working in various petrochemicals positions I have used a company called Furmanite http://www.furmanite.co.uk/ for in-situ machining on, for example, wellhead Xmas trees, large compressor crankshafts, etc. Worth talking to them at they are very capable. When I have used them their rates were not too outrageous.

Ok an update for anyone following this tedious thread of mine.
Tried the company Furmanite but the quote was several times the value of the boat. Another company Metalok in Coventry said they could do it but failed to quote.
Talking to a shipwright via the Jester group received good advice and reassurance that my plan may be viable.
Trawled the web and came across South Devon Railway Engineering and following discussions they say "yes" they have the machines and skill to ghe job and a very reasonable quote. Now intending to proceed and delivrr the keel to ghem. I will report back on results and post videos etc. Thanks to l .

 

[Norman_E]

I hope that the studs can be drilled out, but if they are really the J shaped ones cast in place it is probable that they are full diameter and unthreaded for most of their length, therefore there will be no threaded hole to screw in new studs, just a plain one needing tapping for oversize studs. You need good advice about how deep the new threaded holes need to be.

 

[Keith 66]

I would think it unlikely that they will be cast in with a j head. Studs were far more common in the industry. Thread depth for keel studs should be a minimum of
3 x the diameter.