View Full Version : Copper Rivet 101

05-10-2013, 07:22 AM
Can someone educate me on the use of copper rivets. Or point me to a resource? It looks like I can save a lot of money using them instead of bolts to reattach butt blocks and attach frames to floors.

As good as a bolt?

Easy to do?

Difference between rove and washer (burr)?

Difference between cut nail, common nail, square nail, and threaded nail? Which is best?

Peerie Maa
05-10-2013, 08:43 AM
We are going to have to sort out language. These are square boat nails and roves, you might know them as burrs.
We would use a flat washer when heading up a thicker bolt.
These are cut nails, not for clenching over roves:
I doubt that you will find nails and roves thick enough for fastening frames to floors, but you can use copper round bar headed up in a vice and clenched over a washer or rove made by punching a hole through a copper disk.
Here is how you clench planking or a but block.

Just as good as a bolt, but you will need a helper.

05-10-2013, 08:57 AM
Hmm. So what am I looking for that would have a wide enough diameter head? A&R used rivets originally to attach the butt blocks and frames to floors. Does a burr and rove serve the same purpose? Burr is what I think of as a a copper washer. My original A&R rivets have very wide heads. Or is that created by the bucking process?

Peerie Maa
05-10-2013, 09:06 AM
Hmm. So what am I looking for that would have a wide enough diameter head? A&R used rivets originally to attach the butt blocks and frames to floors. Does a burr and rove serve the same purpose? Burr is what I think of as a a copper washer. My original A&R rivets have very wide heads. Or is that created by the bucking process?

I was wrong, burrs are not the same as roves. I think that burrs were used when riveting jeans or leather work. They should not be used when clenching nails in boats, as the conical form of the rove tightens around the shank of the nail and makes for a stronger fastening. The bucking process will not increase the size of the head, they may have used nails like these:
http://www.samuelkirk.co.uk/ekmps/shops/samuelkirk/images/copper-nails-38mm-box-1000--10746-p.jpgBritish boatbuilders would not use those for structural fasteners, in case the thin head deforms or pops off.

Ian McColgin
05-10-2013, 09:27 AM
There are numerous issues behind a fastening choise including material strength, diameter required, type of holding power, speed of installation, and costs of both labor and material.

Copper is a ductile material which makes it ideal for rivits since the ends can be easily peened over. Rivits are nice where you don't have enough wood to establish holding power by the fastening grabbing the wood in the hole, as nails, screws and trennels do, and where you don't want a big nut sticking out as happens with a bolt. So rivits are most in favor for holding the edges of planks on lap strake boats and for methods like strip plank-tight seam to hold narrower planks to more but lighter frames.

Screws are now the most common way to hold planks to frames. In the past and in many yards today, the motto is "nail where you can, screw where you must". This comes from the notion that nailing is faster than screwing but slightly less secure in tension. So you might nail where the bend in the plank is modest but where you really had to apply large clamping pressure just to hang the plank, you want screws. In a few places you might even want bolts, though bolts introduce the problem of a hole all the way through. Modern drilling methods and power driving screws have made this distinction obsolete for many lighter construction methods, but the attentive reader of this Forum and of WoodenBoat Magazine will recall numerous complaints about the difficulty of finding quality screws for planking that's over 1/2" thick.

A well sized screw has the unthreaded cylindrical section long enough to get a bit past the place where the two bits of wood join, thus maxamizing the cross section for shear strength.

Bolts are totally best where you need both shear and pull as in keel, floors to frames, clamp and shelf to frames and sheer strake, etc.

Round shaped nails can, as they grow larger, be prone to splitting the wood unless you drill a pilot hole in which case you might as well screw. Square cut nails when driven correctly cut the wood grain and thus lessen the chance of splitting. Boat nails are round nails with cut rings on the shank to increase holding power.

Drifts are like nutless headless bolts or rivits - just metal rod banged in place. These are most commonly used to hold broad boards together in rudders and centerboards. If you look at traditional boat construction plans, you will see the interesting staggered drift patterns used.

Copper is only good for the lightest nails, rivits, and sometimes drifts. I see no reason on a boat to use copper screws. Bronze is of course the wonder metal for screws and bolts with monel an even more expensive but stronger alternative. Both generally resist corosion in wet places and while potentially a little more ductile than ferrous alloys make up in trouble-free longevity . . . assuming no nearby ferrous metals that would cause galvanic action. Iron is much under-rated and is really strong and long lasting. Steel is very strong for a given dimension but subject to oxidation and galvanic action. Stainless is in many places overused and over-rated. It's strong and very durable so long as it's not over sealed. For example, you can put a ss bolt into a threaded epoxy hole and it's great. If you just plant the same bolt in wet epoxy, you can set up an anoxic environment for corosion.

A word on trennels. These are wood dowel like things that need to be made of a very durable wood with a grain that does not move water along. Black locust is the very best wood for this in yacht sizes. Trennels need to be sized at about 1" diameter for every 100' of waterline boat length. Thus, they are about three times thicker than any metal fastening you'd use in the same place. In new construction this is a huge disadvantage since the labor of drilling and pounding is a great pain. But as boats age, the metal fastenings enlarge their holes with the shrinking and swelling of the wood and with movement and stress. Rivits can often be tightened up just by retapping the ends but screws and nails loose their grip, water gets in damaging the wood of plank and frame, and all that. When refastening you need to put a larger fastening in even if there's no wood damage. By the time you get a bad fastening out, you've often left a hole that's about as big as a trennel would make anyway so why not ??? Because of their much larger diameter and being made of wood, trennels do not enlarge their holes the way metal fastenings do. With a rot free wood like locust, they will outlast your grandchildren.

Lots to learn. Have fun &


05-10-2013, 09:31 AM
see http://www.diy-wood-boat.com/Rivets.html

05-10-2013, 09:48 AM

Ian. I am screwing planking to frames. I'm just talking about the frame to floor attachment and butt blocks. I thought one does not use screws in butt blocks because of the danger of splitting the wood since you would be placing screws very near the end grain.

The DIY article is pretty good. I'm still unsure what kind of nail has a really big head on it such that it would have good holding. Maybe I will just use bolts

Nick--just read what Chappelle wrote about riveting and he interchanges rove and burr. But if you look at what the online vendors have on their websites, it appears that a burr is like a washer and a rove is somewhat conical. A&R appears to have used burrs. Roves seem to me like they would be easier to use as they must be forced onto the nail.

It sounds like the guy with the buck may have a crappy job. That may decide the question for me since either my daughter or wife will be person with the buck and if its a tough job that aint gonna work

05-10-2013, 10:17 AM
Hmmm. Also, now that I have seen pictures of what the end of the nail should look like when peened over, I am worried that many rivets in my butt blocks may need replacement. I see very little material peened over and some burrs have even fallen off. I assume from the peened over material corroding away over the years. Not sure as I didn't realize this could be a big issue so I wasn't looking at it very closely. Maybe the blocks above the waterline are in better shape. Another item for the list.

Eric Hvalsoe
05-10-2013, 10:48 AM
I seem to use slightly different language. 'Rivets' are square shank, copper usually. Copper 'roves' are those raised cup thingies. Square shank rivets grab ahold of roves much better than round copper nails. 'Burrs' are basically flat washers, but I usually use the cupped roves. When I am setting a rivet and rove, I call that 'riveting' or 'peaning'. The slender tapered nails with flattish wedged tips I call clench nails, typically copper, and are simply curled back into the wood, without roves or burrs. That is what I call 'clenching'. Whatever you want to call them, I also get my rivets, roves, and clench nails from faering. You might also want to check out Davies in the UK (?).

05-10-2013, 10:58 AM
Here in the US there are readily available two distinct type of copper nails.

The first type which are easy to find and come in only a few sizes are commonly known as "Slating Nails" These are used to fasten roofing slates and have a thin, wide head not good for boat building. Stay away from these (Although I have seen plenty of them used in small boat building, either in ignorance or as an "economy" or both.)

There are also available, copper common nails, sold by the "penny size". These look just like a common steel nail with a proportionately thicker and smaller dia head. (Not to be confused with a "box nail" which is thinner and lighter but also sold by the "penny size").
I have used these common nails quite a bit, they are available in almost all sizes. For larger size roves (for floors, knees etc.) I have used US pennies dated before they were a composite, or 1/2 x 1/8 copper flat bar stock and just nip them off and drill/punch a hole. These homemade roves are square but they work perfectly (I like the way they look and work). I drill the hole undersize and then expand it with a punch, this makes for a reinforced hole less likely to buckle or go concave while you are taking up the rivet.
A cupped profile rove can be created by simply striking them with a ball-peen hammer on a chunk of lead this work hardens then a bit making them stiffer..
(Jamestown Dist. has copper common nails and burrs (the burrs seemd a bit thin to me and I always made my own.) http://www.jamestowndistributors.com/userportal/show_product.do?pid=1925)

Slating nails

Common nails


Peerie Maa
05-10-2013, 11:20 AM
^ I agree with everything that Ian posted except that you should always drill pilot holes for every fastening that you drive. There is a good rule of thumb for pilot hole diameter with square boat nails: in hard wood use half of the diagonal across the corners, for softwood use the width of the flats.

05-10-2013, 11:31 AM
Chuck, A copper fastening is a beautiful thing, lasts as long as any metal fastening could, but for your situation, I would be buying a few boxes of bronze machine screws, carriage bolts and appropriate nuts and washers, particularly since you are not working with an experienced crew, it will be loads faster and easier to re-bolt what used to be riveted, none of us can live long enough to outlast these new bolts... Cheers, Steve/BT

PS, I do like to keep a bit of copper rod and copper flat washers in 1/4, 5/16, 3/8" sizes in the truck, for fabricating that one or two odd, out sized fastenings that could stop the train...time and tide wait for no man and all...

Bob Cleek
05-10-2013, 11:43 AM
Where strength is a requirement, bronze is far stronger than copper. Thus, for the same strength, the copper fastening has to have a much larger diameter. This creates a "diminishing returns" situation in some fastening situations. When fastening floors to frames, for instance, the larger the hole drilled through the frame, the weaker the frame becomes at that point. Bronze avoids this problem because the drilled fastening hole can be of a much smaller diameter. Another challenge frequently encountered with "heading up," whether it be rivets or drifts and such, is that you have to have the space to swing the hammer. Often, the various adjacent parts of the boat may interfere with swinging the hammer. Here, also, a bolt is called for. Bronze bolts, particularly in larger sizes, are now extremely expensive. Considerable savings can be realized, and greater flexibility in materials inventory requirements, but purchasing properly sized silicon bronnze nuts, Silicon bronze or copper (can be homemade) washers, and silicon bronze rod, which can be cut to the length needed and threaded as needed with a die.

Jay Greer
05-10-2013, 12:21 PM
Here is a bit more on the actual process of riviting. Having a helper to buck on the head of the nail is not always necessary if you are working with a small boat that allows access to both the inside and outside of the planking being hung. Some builders have special bucking irons that can be hung and clamped from the plank edges therby allowing one man to do the job of two. The advantage of British boat nails is that they have a square shank that is the same diameter throughout their length. The conical rove is smaller than the nail shank and when driven on, with a hollow punch, the rove grips the nail shank with great tenacity allowing the mechanic to then peen the nail which, should be nipped off, first, to about the diameter of the shank. This is a matter of instinct that will develop once one gets into the work. If the shank is too long, it will buckle and if it is too short it will not grip properly. So one learns as the work progresses. Sound and rebound have a lot to do with riviting. A peening hammer must match the nails being driven. Too heavy it will tend to buckle the nail and too light it will brittlize the metal and the end will split and fail to draw properly. British rivet peens have a rounded cross flat head on one end that allows more control than US Ball Peen Hammers. Peens are best kept buffing wheel polished as a polished hammer will leave a polished mark. When all is right, the sound of peening will be a dull taping sound. As the rivet begins to draw, the sound will become brighter and nearly rings. As the head forms, near the end of the draw, it then should be lightly peened around the edges in order to form a dome shape. On small boats, I use a special punch that is used by jewlers called a "dapping Die". This is a hollow punch that smooths over the head so as not to produce snagging of skin or fabrics over the peened ends. Dapping dies are available from jewelery supply houses.

05-10-2013, 02:32 PM
Fun stuff! I am learning. As usual, you guys, are a font of information.

I have done some looking around and have yet to see a copper nail with an oversized head on it. Except the slating nails that canoeyawl psoted a picture of. I actually have some of these and the head, though a decent diameter, its pretty thin.

05-10-2013, 02:46 PM
fyi--faeringdesigninc.com appears to have suitable nails with big heads. (I think this is the company Eric was referring to).

The cost savings is not as great as I thought. Once you get up to 1/4" copper nails, the savings is gone--at least at faering's prices. Possibly because the bigger guages are in really long lengths--6"--which I don't need

05-10-2013, 04:12 PM
It is very easy to head-up your own nails, or bolts especially in the larger sizes. No waste, just buy some bar stock and cut to length.
With copper you can head them cold if they are annealed, but with a torch it is faster to heat the head and work it red hot. Bronze is more heat critical, but it only takes a couple of trys to figure out the correct temperature. In my experience, bronze makes lousy (cold) rivets because it work hardens so hard, so quickly. The head becomes hardened and the shank is still malleable and will bend in the joint resulting in an ineffective fastener.

Humans have been making metal nails for a long time. Try it, it's fun and not a big deal.

Jay Greer
05-10-2013, 04:48 PM
Not to disagree with Jay, but.....

It is my experience that using a finishing punch or "dapping die" I think can cause shank buckling to the inexperienced..... sorry. It is my experience that using this tool the force is directed vertically down the shaft and too brutal hits will buckle. You can change the angle slightly by tilting it but you run the risk of denting the plank with the edges of the punch - just my experience.

You shouldn't need one of these. I have just banged in 5,000+ of these little buggers and my way is to pein over with the hammer in a "round the clock" direction. Tap the very edge of the cut shank and you will by default create a domed head, you may want to go round twice. After each rivet I run a finger round the rove and if I find a sharp edge - give it a couple more taps. The hammer should skid off the rivet and leave a dark mark on the plank - done properly this is not a bruise but the oxidised copper residue on the head of the hammer rubbing off.

Some recommend a couple of taps stright down on the head to "firm up" - but I think this is more of a signal to the dolly man beneath to move to the next rivet.... contentious maybe.
Indeed you are correct! Using a dapping die in place of peening will, most likely cause the rivet to buckel. Unfortunatly I failed to mention that the Dapping Die is used after the peening is complete and not as a primary heading tool.

05-12-2013, 05:03 PM
Chuck we ended up having our rivets made on a CNC screw machine for not that much more than a bronze bolt washer and nut .


If you can use them , I have a large bucket of rivets that we took out , just need to be cleaned , 60 years , no failures :) Bob


The rivets look cooler and cleaner than the bolts and nuts

05-12-2013, 07:39 PM
It's been a while since Olinka's varnished bilges have graced the pages here. It looks like the re-fit is going well. Still at Wayne's?

Jay Greer
05-12-2013, 09:46 PM
That is blindingly beautiful!

05-12-2013, 10:50 PM
Still at wayne's :) Work started back up last month .

05-13-2013, 06:33 AM
Those are some pretty rivets. Thanks for the offer. I ended up ordering bolts.