Trenails - how to make them ?

sarabande

sarabande

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I am toying with the idea of making an oak frame for a shed, and to make it all simpler (ha !) thought about some green oak trenails.

These are about £1.50 each at Yandles (tapered and dried oak), so it seems to make sense to DIY.

I gather one needs a thick steel plate, a hole of the appropriate size, and a gert big hammer.



Can anyone suggest a slightly less energetic method, using perhaps a band saw and a spokeshave ? And, NO, I really am not into lathes ....
 
Trenails - The WoodenBoat Forum - WoodenBoat Magazine
forum.woodenboat.com › Tools / Materials / Techniques / Products‎
Mar 2, 2001 - 39 posts - ‎7 authors
Has anyone here made a number of Trenails? If so, how did you do it? Start with a big tree and ..............?
Trenails vs copper rivets 50 posts 11 May 2012
More Trenails 50 posts 9 Mar 2001

http://forum.woodenboat.com/showthread.php?17876-Trenails
 
On the TV programme Treetops Pavilion they made their own trenails. They had the local blacksmith weld a short tube to a thick steel plate. The bore of the tube, and hole through the plate, was slightly larger than the diameter of the trenails. The tube was dressed down to the required diameter and sharpened on the outside. I believe they case-hardened the cutting edge to maintain sharpness.

Paul
 
Bandsaws, spokeshaves, or lathes don't really cut the mustard. The point about the hole-in-the-plate method for making trennels is that is gives you straight-grained fastenings. The last thing you need is for a trennel to be cross-grained.

But failing the use of trennels made the traditional way, you might consider the use of drifts, copper nails, or possibly other fastenings instead.

Mike
 
Mike

with respect to your forum ID, I don't understand how I can't roughly prepare trenails/trennels say to a 1 inch cross section and 6/8/10 inches long in a bandsaw along the grain, prior to forcing them through a tubular die. I was trying to work out a method roughing out about 100 nails without having to manually shave each one to the right diameter.

Tha last thing I would trust is an oak beam (they will be in a framed shed) relying on a cross-grained trenail :)
 
Wooden Boat Fittings said:
Bandsaws, spokeshaves, or lathes don't really cut the mustard. The point about the hole-in-the-plate method for making trennels is that is gives you straight-grained fastenings. The last thing you need is for a trennel to be cross-grained.

But failing the use of trennels made the traditional way, you might consider the use of drifts, copper nails, or possibly other fastenings instead.
Click to expand...

I echo Mike's monition to forswear 'cut' means of production of trennels ( sic! ) in preference of split and slice-trimmed means, for such 'cut' trennels will be far weaker than split, and are likely to fail in droves when driven hard home into a timber joint..... then you'll need to remove the broken bits, and try again. That implies a suitable 'froe', a seat-bench, and a steel plate with a suitably-sized 'ole.... and an oak or beech-wood mallet. You may also need an 'English shavehorse' trimmed to your leg/arm/bum topography, and suitable travishers and twybils. See here - http://woodsmithexperience.co.uk/shop/category/devices


db_file_img_70_1000x1000.jpg



I'm wondering why you have plumped for grown oak, from which to produce your tren'ls - apart from your having lots of pieces to hand. Willow was the material of choice for centuries, appearing in many archeological finds, including this one - http://www2.rgzm.de/navis/ships/ship002/Ship002Engl.htm

It is relatively easy to strip bark from willow staves of the right grown diameter, cutting off the unwanted thin and thick, and leaving the pins 'just so'. The remaindered material works well in thatching and the weaving of rustic fencing, etc. such that there should be little waste. It can, of course, be replanted to regenerate itself.....

Of course, the ancient woodcraft construction skills are very satisfying to employ - for a while. After that, I sense that most would reach for some 3/4" threaded galvanised bar, nuts and plate-washers..... 'cos that's swift, cheap and effective, and likely to last a lifetime.
 
Ah well.... Trennels (or trenails, or trunnels, or treenails :) ) can all be cut or shaved roughly to shape before the banging-through-the-hole process I suppose, if one is careful. If they are cross-grained, banging them will probably break them then and there anyway. But better is to split them first to just a bit oversize -- that way you know the grain is true. What the hole in the steel plate does is just to round off the corners for you. Since these trennels are for a barn, not a boat, then if you have a good eye and are handy with a froe (or even a chisel) you can probably forego use of the steel plate altogether.

Mike
 
Many ways of skinning a cat...

From a woodwork forum: some alternative suggestons.

"I've done them by riving with a froe/splitting with an axe and shaping with a drawknife/banging through a hole etc, but I've settled on a bandsaw only technique, its quicker.
Select a piece of dry (kilned) oak about two foot/600mm long with a really straight grain and rip it into square rods the same size as your hole, maybe 20mm or so. Then set the bandsaw table to 45 degrees and set the fence so you can cut the square rods into octagons, with the fence to the right of the blade and downhill, rotate the square rod each cut and you get an octagon, bingo. If you then hold the back end of a rod with the front half of it resting against the fence,push it and in and out twisting as you go you will round it over against the running blade. When the front half is rounded over swap it front to back and round the rest. you should now have oak dowel. The reason for the two foot length is to keep your hand away from the blade, you could go a bit longer if it suits your set-up. Cut the dowel into suitable lengths, make a tapered end (I just use a sharp chisel downwards against the bench) and proceed.
I echo the previous comments about draw boring, using dry pegs in green oak. I offset the holes by about 3mm and use a peg/trenail about twice as long as it will finish up, so I can have a long taper and chance to trim the splintered end I've been whacking.
Banging a peg in and seeing the joint come up tight is one of the most satisfying things in woodwork for my money, so go for it."
 
That looks a very laborious way of making dowels. Much quicker is to welt a cleaved blank through a sharpened mandrel as described earlier. The ones I've made where not as big as those in the video so maybe use a bigger ammer.
 
Are you essentially looking for a large dowel maker? This can be done by taking a piece of steel plate and drilling the hole of the appropriate size and then drilling another, smaller hole so that they just break into each other. Then take your square peg, taper the end to get started, clamp it in a drill and drill it through the hole. The sharp edge from the small hole then strips all the excess wood leaving you with a perfectly round dowel.
 
excellent set of videos, PuffMD, thanks. Though it does raise some questions:

I see the trenails (sp?) are turned on a lathe from square section, then one end cut off, and a cut made in both ends for the wedge. Any suggestions for what wood to use for the wedge ? It looks like ash, but might be elm for waterproofness and rot resistance ?

I would become a bit OCD about the orientation of the wedges, and want to align them all in the same way to make them then look really neat :shameicon:

I don't see how the drilling at varying angles (video 2) really pulls the frames together. Timber frames of that size, with dozens of trenails, are not going to be amenable to slight angular differences ?


More than anything else, those videos make me appreciate just how much manual labour must have gone into ancient shipwright work, with every hole having to be drilled without the benefit of electricity and without modern metallurgy giving edges that keep.


And PM. I had to work out what you meant. I think you end up with two holes which are contiguous, like a figure of 8. That means a pretty precise double drilling to obtain the desired diameter. Nice, simple technology. :)
 
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Yep Sara, you got it. Jigs are your friend and you can easily set one up so that an ordinary hand drill will be acurate enough to drill the two holes. One thing with an Oak frame construction is the movement, I hope you have taken this into account. Many people have to fill quite large holes in the structure as it moves quite a lot over time.
 
I know how it works in practice, PM, but how does it work in theory ? (Old joke).

My putative shed is going to be made from a mix of green and dried oak, as I can get dried straight pieces, but need knees and crooks from green.

Having absorbed all the discussion here, I'm going to make a couple of trial pieces with cross-halving and corner bridle joints to see how it goes. Then some trenails and my 4lb club hammer :)
 
The problem with the two-hole approach is that you would be removing material to the whole depth, giving problems with 'chatter' and 'grabbing'. The gadget that appears on the videos uses the 'pencil sharpener' method where the change from square to round is more gradual. Given access to a metalworking lathe it is quite easy to make such a gadget.

Re drilling at an angle, this is similar to when we nail two boards to each other; the fact that the orientation of the fasteners is not parallel keeps the two pieces together and prevents their being 'worked' apart. Try it with nails on two scrap pieces of wood and then try to prise them apart.
 
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