Replacing wrought iron bolts through deadwood

tara123

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Hi
I am in the process of replacing four half inch by three foot long bolts that run either side of the stern tube holding together the oak deadwoods on my 32' motor boat.
I am pretty sure all the bolts are well waisted and therefore require replacement having removed one bolt, in pieces, by plenty of hammering, drilling and swearing.

My intention now for the remaining three bolts is to use a 17mm hole cutter tig welded to a seamless steel pipe and cut around the old bolts completely. The complete drill bit will be approx a metre and half in length thus allowing me to drill from the top through a carefully aligned access holes in the laid teak aft deck.
The inside diameter of the 17mm cutter will be slightly oversize the old bolts and therefore hopefully will not bind on any solid bits of bolt if the cutter heats up.
Obviously the whole drilling process will be done slowly regularly clearing any sawdust.

The new bolts are to be made from 5/8 nickel aluminium bronze rod and will be therefore be approx 1mm undersized in the 17mm hole(sorry for the mix of metric and imperial)
I am assuming that the 1mm gap will not be a bad thing allowing the oak to swell as it is currently quite dry with the boat out of the water over the last 8 months.
It is my intention to fill the hole up with a tar paint prior to pushing the new bolt home leaving the new bolt embedded in tar. Epoxy tar??

My main worries are running off line with the cutter and either coming out the side of the dead wood or catching the side of the bronze stern tube however I keep trying to comfort myself that the remaining bolt and easy pathway will keep it on target.

Is there anything fundamentally wrong with what I am attempting or has anyone comments or advice on the above other than to sell the boat and buy a plastic one.
 

andy01842

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I think that saw dust is the main problem with you plan. You must have some where for it to go! Taking the cutter out to clear the saw dust is ok for a few inches but 3ft is another matter.
Hitting a bolt with a hammer makes it shorter and fatter, there for tighter. If the bolt can be pulled out it will stretch and there for be thinner and looser. Having said that a pneumatic hammer is a wonderful tool. It is more like vibration than a big hammer banging away. I have seen a cylinder liner put in with such a tool and you would never do that with a hammer.
I would drill a hole in the end of the BOLT to locate the drift and try a pneumatic hammer. Don’t push the hammer to hard let it do the work. If you can rig up a way of pulling the bolt out with said hammer it could be an easy job, best of luck.
P.S. welcome to the forum
 

tara123

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Thanks Andy for your comments.

The cutter has slots cut into it an angle just above the teeth to allow swarf/dust to gather. I aim to drill say an inch at a time and remove the cutter to clear the dust from the slots.

I would love to be able to remove the bolts by impact of some kind but believe that they are well beyond this through corrosion.
I fear that whilst I may retrieve some of the bolts at each end using a puller I will be still be left wilt a portion of rotted bolt in the middle.
To then start and hammer the remains even with a concave punch has a high risk of collapsing and jamming the remaining bolt.

All of the above happenned with the first bolt as it had necked right through in a number of places and it eventually took me two days to get all remains cleared.

It may however be a better idea to remove as much of each bolt at either end with a puller and then use the cutter on the remainder. If I can get about five or six inches of bolt out it would help keep the cutter in line from the start?
 
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I've a home made tool I cobbled together last week, not for pulling bolts, but for deck spikes, basically a pair of mole grips, welded on to the adjuster thread is a length of round bar, then the barrel of a slide hammer (big fat round lump of metal with a hole down the middle slid down the bar, and lump of steel welded on the other end of the bat

made it for pulling deck spikes, seems to work, clamp the mole grips over the head, and then slide the metal barrel up bar hitting it against the plate at the end

and bugger me it works really well, and doesn't need a huge amount of force, but does take a while

ok you still stand the chance of the bolts giving somewhere along the way, but might get some or all of it out before resorting to the big guns (or drills!)

I also ground a Vee notch in each cheek of the grips to get a it more purchase grip

so picture this, I'm sat on deck, said tool clamped on something between my legs, right arm moving up and down in a particular time honoured repetitive fashion...... anyone witnessing this from behind me may have been somewhat alarmed /forums/images/graemlins/shocked.gif as to what I was actually doing, they probably put it down as "they're a strange lot these wooden boat owners"

did any of that make sense? answers on a postcard!
 

tara123

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Thanks for that, It is a good idea and well worth trying.

I think it may well be time to ruin another pair of vice grips.

By the way your website is great. I came across it in the past and found it really interesting. My own boat is a fishing boat type hull, larch on oak being built in the Thornbush shipyard in Inverness.
 

tara123

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Thanks Ben, I think that is the best way forward.

meant to say in my last comment.. larch on oak having been built in the Thornbush shipyard ( during 1960's)
 
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interesting... not heard it described thusly before!

was it a working boat? if you've got names or numbers, might have some old pics, got heaps from the moray firth

thornbush has long gone now, ironical that that one of the last things they were doing there was cutting up old boats that were being de-comissioned including some they'd built themselves - criminal really but hey ho who can argue with brussels
 

tara123

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No, never worked.

She was brought over to N Ireland as an open boat and a fitted with a teak cabin and wheelhouse by Bangor boatyard NI.

I would be interested if you knew of the hull design as she is not of the traditional canoe stern. Will try and send a pic

Funnily enough our family have bought it back on three separate occasions, twice from the same person.
 

cliffordpope

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Best of luck! I've been there, albeit with shorter bolts, but similarly corroded away virtually to nothing deep inside the wood.

I suppose ultimately you could ask, do you absolutely have to get the bolts out, or could you just leave the remains and drill a new hole a few inches along? (In my case there was no choice - they were keel bolts which had to go through the middle of the floors and align with holes in the cast iron ballast keel)
 
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Built in Bangor? Possibly by Dickies maybe? counter stern? transom stern?

intrigued now!

certainly sounds up their street, they built a lot of work boats, but also took the same lines and made pleasure boats as well, they were also know to knock the hulls together in tarbert and do the fit outs in bangor. A very good and much loved builder in their day.

not 100% but think, the 'descendants' of dickies still run a yard in tarbert, (although I could be 500 miles out and they are in Southampton!) and kept all the records/drawings etc from the various yards they opened around about the place

wills ee if Ic an find numbers/info
 

tara123

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Hi

I did think about it but have only about half an inch of wood between the stern tube and the hole whenever the drill would be a foot down. The last thing I would want to do is nick a hole through the side of the tube.
The old bolt hole and remains will hopefully act as a guide for the cutter
 

tara123

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No, Bangor boatyard in Belfast Lough not Dickies in Bangor Wales.

It has a counter stern with tumble home.

I haven,t figured out yet how to post a picture. Can you pm a email address that I can send a couple of pictures to.
 

Peterduck

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Yes, the bit will follow the line of least resistance; in this case, the previous hole. As previous correspondents have suggested, draw as much of the old bolt out of the hole as you can, before sending anything down the hole to ream it out. If you ream from the bottom upwards it will help the cuttings to clear from the hole. I would not try to ream the hole any larger than it already is. If there is any portion of the old bolt still left in the hole, it will be better drill through the rust rather than through the wood. Where the bolt has rusted, the expansion of the rust (8 times the volume of the corresponding iron) will have compressed the surrounding wood, thus enlarging the wooden hole.
Peter.
 

tara123

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Thanks for that David, yes the cutter I am having made is roughly the size of the enlarged hole. The inside edge of the teeth wil have .5mm clearance around the original bolt.
I am happier going to a larger size (from 1/2"to 5/8 )as I will be replacing from iron to bronze
Hope to have a go at it at the weekend and will post how it went.
I have now replaced to date 88 floor bolts, 9 keel bolts and 4 bilge keel bolts but these are the most daunting.
 
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