For Todd--Bronze Holdfast Nails

[Dave Richards]

Here you go Todd. Hope this photo shows what you want to see. They aren't quite ring nails but similar. Hamilton Marine does class them as ring nails. I could imagine a number of applications for these in places where disassembly wouldn't be required but weather resistance is. These are silicon bronze.
http://www.woodshopphotos.com/albums/Dave-R1s-Album/BronzeNails.sized.jpg

Just for the fun of it, I took another photo of some one inch copper rivets and roves. These are 14 ga.
http://www.woodshopphotos.com/albums/Dave-R1s-Album/rivetsnroves.jpg

[Todd Burch]

Thanks Dave. What is the application for the rivets? Do you use two hammers to install them?

[Dave Richards]

The typical application for the rivets is in lapstrake-built boats to fasten planks to each other and to fasten the ribs to the planks. Traditionally the rivets are the only fasteners used between planks and the planks are allowed to swell once the boat is launched which keeps the water on the outside. This is similar to coopering in which barrels made to hold liquids must be soaked to allow the seams to close up.

The process for setting copper rivets is as follows"

1. A hole is drilled for the rivet through whatever is being fastened. The diameter of the hole should be a hair less than the width of the flat on the rivet.

2. The rivet is driven through the hole until the point is out far enough to catch the rove. While driving the rivet at this step, the wood is backed up with a bucking iron which may be an automotive type iron or, as I use, a small cross peen maul with the faces polished. Obviously, you must hold the bucking iron just to the side of the hole so the rivet will come through.

3. The rove (sometimes referred to as a burr) is slipped over the end of the rivet concave sight down and backed with a rove set. My rove set is a large bolt with a hole slightly larger than the rivet drilled in the end. While holding the rove set against the rove, the rivet is driven through until the head is seated against the wood or slightly countersunk.

4. The rivet is cut off fairly close but not flush to the rove.

5. With the bucking iron held on the head of the rivet, a small (2-4 ounce) ball peen hammer is used to slightly flatten the rove. 4-8 light taps are all you need on the rove. Then the end of the rivet is peened over. This is also done with light taps with the flat face of the hammer.

If you whack the rivet too hard, you run the risk of driving the body back toward the head, bending it. This can result in the joint loosening with time.

It all takes much longer to tell about than to do it.

FWIW, another method is also used to fasten planks on boats with overlapping planks. In this case a copper nail is used. It differs from the rivets shown in that two sides of the nail taper toward each other so it is more wedge shaped.

The nail is started, again through a slightly small hole and backed with the bucking iron (although it is called a clinching iron instead). As the nail begins to protrude it is driven into the clinching iron bending the nail across the grain and turning the end back into the wood. the nail is fully driven and turned back into the wood. this is referred to as clinching, or clenching. The term clinker as in a "clinker pram" is derived from this fastening method.

There you go. way more than you wanted to know.