What sort of bolt are these?

[samb]

I'm working on an 18' old town HW. It had mahogany gunnels which need replacing. I'm trying to keep it looking original so need to drill, sink and plug the holes where bolts go through. The original bolts in the photo had to be cut so I can't reuse them. Does anyone know what these are called and especially where I can get some. Extra points if you give me a supplier in the UK.



Thanks
Sam

 

[Denise MsWdnBoat]

don't know about those.. but I was under the impression that all Old town wood canoes used diamond head bolts

 

[Benson Gray]

I was under the impression that all Old town wood canoes used diamond head bolts

Old Town didn't start using diamond headed bolts until around 1923. His canoe described at http://forums.wcha.org/showthread.php?13000 is from 1920.

Benson

 

[Denise MsWdnBoat]

Sam could you weld or braze them back together or have someone make New?

Benson, is it necessary to be historically correct?

 

[Larry Meyer]

I've never see bolts like those. Could it be the "ears" below the bolt head are intended to go in slots and that therefore the bolt would not turn when the nut was tightened?

 

[Benson Gray]

is it necessary to be historically correct?

The answers to questions like this usually begin with "It's your canoe ..." so it really depends on what the owner wants. I suspect that an ordinary carriage bolt would work fine but Sam can decide what he prefers.

Someone brought a canoe back to the factory for repairs in the 1970s. It had been built with diamond headed bolts made out of galvanized steel during the Second World War. The canoe was repaired and the old rusty bolts were replaced with new brass ones. The owner was horrified when he came to pick it up. They dug around and found some new old stock galvanized ones to put back. The owner was much happier to have it returned to the way it had shipped originally. The customer is always right.

Benson

 

[Craig Johnson]

I believe those bolts were used when the bolt head was countersunk and plugged. Yes the ears keep it from turning since the head can't be accessed. You might use a carriage bolt so the square part will keep it from turning and grind the dome flat and a little smaller to accommodate whatever sized plug you want.

 

[samb]

Thanks for the replies. The ears are there to stop the bolt turning because once they've been put in the hole and the hole plugged they need to stay in position when you use the spanner (wrench) on the nut. I'm not specially interested in historically correct, but I do like the idea of clear gunnels. If no one knows where I can get some at a reasonable price, I'll make some up (or a variation) by silver soldering bits onto brass threaded bar. I'll have to have a good look round the knock down furniture sites to see if I can find something that will do the same job.
Sam

 

[Greg Nolan]

I am not aware of anyone making bolts like the ones you removed from your canoe.

The flanges or ears on the shaft of the bolt are clearly intended to sink into the wood as a nut is tightened onto the bolt; I doubt that it is necessary to pre-cut a slot, just as it is not necessar to cut a square section in a bolt hole when fittig a carriage bolt. The flanges serve the same purpose as the square section under the head of a carriage bolt.

The only things that I have found at all similar are timber bolts, which are usualy large and galvanized < https://www.boltdepot.com/Timber_bolts_Hot_dipped_galvanized_steel.aspx >

or rib neck carriage bolts (in the UK, even) --
< http://www.fastenerdata.co.uk/fasteners/bolts/carriage/unc-rib-neck-carriage-bolt-sae-588-b185.html > -- I don’t think these would work well in wood except perhaps in very hard dense wood, because the ribs are not very deep.

I would think that new carriage bolts (preferably silicon bronze) would work just fine if properly countersunk.

 

[samb]

Thanks Greg - give yourself extra points for the UK supplier!
I've thought about carriage bolts - they'd be even better if I grind the head diameter down a bit. The small heads on the original meant that the plugs covering them were nice and small - very neat. I'm way off the stage of needing them yet so I'll leave the ideas to ferment in my mind.

On a slightly different topic, did old town stain their mahogany seats and rails the typical old red mahogany colour you see on antique furniture - or just varnish straight on? I ask because my build record shows a "red mahogany stripe". There are traces of a reddish stain - or may be paint- on the inside of the inwhales and as the whole gunnel assembly was in such poor state I couldn't tell if they'd originally been stained, or whether the colour was my guide for the stripe on the finished boat.

Sam

 

[Benson Gray]

did old town stain their mahogany seats and rails the typical old red mahogany colour you see on antique furniture - or just varnish straight on?

There are mixed reports on this topic. It appears that they would use stain in some cases and not in others. This probably depended on how much color variation there was in the mahogany they had available. I have an Otca in AA grade from 1927 where the decks have clearly been stained and one from 1936 that has none. The mahogany stripe mentioned on your build record would have been with paint on the outside of the canvas below the gunwales.

Benson

 

[Dan Miller]

They are called fin-head bolts.

Here is one possible source: http://www.ccfasteners.com/cgi-loca...=240&cart_id=1209c52966345c560f0788d0dcf310a8

And if you want to roll your own, there are instructions in Herreshoff's "Common Sense of Yacht Design" - you can find more info poking around the WoodenBoat Forums.

 

[pklonowski]

Fin-Head or Fin-Necked bolts. After not locating a source, I started trying to reproduce them by grinding the head of a hex bolt to size, then asking a blacksmith friend to smash the fins... he didn't bite, said he'd have to make the tools to create the shape, and it would get very expensive. He indicated it would be much easier with brass, but not sure if bronze, or silicon bronze would work well with that method... not to mention what the heating would do for the metals. I didn't get any further.

 

[Jan Bloom]

Color is more a dark brown Mahogany very similar to the color Martin Guitar has used on its Mahogany bodied guitars. This is achieved by using a dark colored filler. A filler must be used on mahogany to get the ultra smooth surface seen on the AA canoes. If you do not use a dark colored filler you ruin the risk of filling the grain pores with sanding sworf which may appear as white specks in the pores of the wood. Looks like s---. But that is my belief and what I do.

 

[VallierOutdoors]

The bolts are fin-neck as other have said. I've pulled them from a number of old Maine canoes. The fins are wide and work well to prevent turning. The British rib-neck bolts probably wouldn't hold well, at lest in softwood. In hardwood, especially if the fit is tight, maybe so. McClave Philbrick & Giblin in Mystic, CT also once sold something similar; maybe they still do. I'd have to go look at my stock but I think the fins are under the head of the bolt, not along the shaft.

As for the mahogany, those filler stains look horrible to me. There are two other options that produce a beautiful finish. First you can wet sand with oil (Tung or whatever you choose), and then wipe off excess across the grain, leaving the sanding swarf to fill the grain. Because it's oil and sanding dist from the very wood it's filling, the results are excellent. The other thing is to sand well and then build up coat after coat of varnish with some wet sanding in between. I've used both methods many times on old mahogany, new mahogany and other open-grain wood, and the results are a mirror finish. To me there's nothing more beautiful than that rich darkness of antique mahogany (well cleaned, of course). Muddying it up with filler is something that I'll never do.