Making Roman Hobnails

[M. Demetrius]

I have a question about a "special nail". Specifically conical headed hobnails, like would be found on Roman military boots. The diameter of the cone end should be about 1/4" to 5/16". The height of the cone ought to be at least a quarter inch.

The shaft of the nail (not important if it's flat or round) has to be about 1/2", so it can go through a couple of layers of sole leather and still have enough to clinch over. It takes about a hundred to make a pair of boots.

Being basically a bonehead, and a beginner, I can't figure out how to make these. Anybody got a good idea? (heck, even a mediocre idea would help...)

The only thing I've though of so far is to make a conical tool to hammer down over the really hot metal of the nail. IOW, knock the longer-than-usual head end into the cone shape, using a conical socket.

Does that make any sense? Sounds like a torch would be a better heat source than the forge for something that small. Then I guess I could use a thin piece of mild steel stock, form the point, set in a header, heat, put the cone on top and smack it a time or two to form the head. Am I thinking right for a change?

[Mike Ameling]

Yes, you can use a flat plate for a nail header. Just make sure that the hole is flared out on the bottom side - or you will get a "wedge fit" with your nail. It does help to have something of a "domed" area around your nail header hole, but that just helps you with rounding/tapering the head - that hammer clearance stuff.

A fairly easy way to get that with a flat plate nail header is to heat your plate up, and drive a large ballpeen hammer into the underside while holding the hole thing over your hardy hole or the end of a larger pipe. This would them "push" the metal down to create that "dome" shape. You also need to start with some pretty good tool steel. A large truck leaf spring would work.

Doug Merkel (sp) makes nail headers like that - but he also draws out one end for a more convenient handle. He "domes" one section, then punches it and drifts it from below to get that tapered hole.

Don't forget to put a little rat-tail loop on the end of the handle to hang it up --- where you won't lose it!

In several of the blacksmithing books there is a drawing of a nail-header combo tool. Eric Sloane's Early American Tools book comes to mind. It was designed to set into a stump or clamp in a vice. It had a cut-off hardy on one side, that nail header in the middle with a slit underneath it, and a lever off of the other side to slip into that slot under the header and pop the nail back out.

A lot of nail makers used a charcoal "brazier" to heat up their nail rods. They kept several in the fire heating up, used a small hand-bellows to perk up the heat when necessary, and kept rotating from one rod to the next when in ... production. That brazier was a lot like the ones used for soldering irons for tinsmiths. Plus nail making was also a ... cottage industry. People worked at home and at night around their fireplace making nails. So it made use of the light from the fire, and the heat for the home - while doing productive work to help pay the bills. If enough tools were available, several family members could be working at one time.

The early Romans used a flat plate as a nail header. One cache of nails found near an old Roman fort in England had 16 TONS of nails in it! The estimate was 875,000 NAILS! They were all made up and ready, but never got used in constructing other buildings in that fort. They were also amazingly consistent in length, diameter, and head size/shape. There is a good book on early Roman iron work in Britain. It is called:

Iron For The Eagles
The Iron Industry of Roman Britain
by David Sim & Isabel Ridge
isbn 0-7524-1900-5

The one author did a prior book about the archeology of Roman iron production in Britain - mining, smelting, bloomery, etc. This book they talk about that iron production, but then went on to produce their own iron billets, and then forge them into tools/weapons - hammers, axes, arrowheads, spears, swords, etc. They also did a time/labor analysis of each step. Very interesting reading.

Roman hobnails. You would need that top tool to form the head consistently. Much like a Rivet Set. Form your nail shank. Cut mostly through your rod leaving enough mass for the head, slip into your header, snap off the rod, set your "rivet set" over it and smack it to form your hobnail head. With practice, it would get easier.

It reminds me of a comment Francis Whitaker made. To paraphrase: to make something, you need to make up 45 of them and throw away the first 40. That ... practice ... adds up.

And the other thought is that the things that look to be soooo simple to make tend to be much much harder to make! Like a shepherd's crook curl on the end of a bar looks soooo simple to make, but getting it done in a consistent and symmetrical manner is the hard part. Or a scroll without any kinks or flat areas in the curls.

Just some humble rambling thoughts to share.

Mikey - that grumpy ol' German blacksmith out in the Hinterlands

[John B]

A fairly easy way to get that with a flat plate nail header is to heat your plate up, and drive a large ballpeen hammer into the underside while holding the hole thing over your hardy hole or the end of a larger pipe. This would them "push" the metal down to create that "dome" shape. You also need to start with some pretty good tool steel. A large truck leaf spring would work.

Please remember not to hit one hammer face with another, use a brass / lead / copper or soft faced hammer otherwise chips will fly

[M. Demetrius]

Thanks for the good info. Should I put this hobnail bit in another thread? I don't want to be a hijacker.

Here's a sketch of the hobnails.



I plan to scale them down to 1/4" diameter and height from the artist's 5/16". Seems like the heading tool could be made by drilling a bar into its end, maybe 3/16" diameter and depth, then heating that drilled end and forcing a "right shaped" 1/4" punch into the hole. That should widen and deepen it enough to do the task. I guess I'd need to figure out how to harden the tool, probably just after it cooled down to red with a quick quench in water?

Which would be less fatiguing over a run of a hundred or two nails--a direct straight punch type, or a handled tool type? Obviously the plain punch would be easier to make...but wood handled tools have advantages, too, once made.

[Bill in Oregon]

Mike: Mucho appreciado on your fine post. The book on Roman iron making sounds fascinating. No truck springs in my junk pile yet, but soon.

[wolfshieldrx]

In several of the blacksmithing books there is a drawing of a nail-header combo tool. Eric Sloane's Early American Tools book comes to mind. It was designed to set into a stump or clamp in a vice. It had a cut-off hardy on one side, that nail header in the middle with a slit underneath it, and a lever off of the other side to slip into that slot under the header and pop the nail back out.

Mikey - that grumpy ol' German blacksmith out in the Hinterlands

What I see in Sloane's book is basically a small stump anvil...no lever to pop out the nail. Or am I looking on the wrong page? bart

[Iron Falcon 72]

Thanks for the good info. Should I put this hobnail bit in another thread? I don't want to be a hijacker.
SNIP

Which would be less fatiguing over a run of a hundred or two nails--a direct straight punch type, or a handled tool type? Obviously the plain punch would be easier to make...but wood handled tools have advantages, too, once made.

Make a wire-wrap handle for the punch-type like these:

http://www.blacksmithing.org/CB-Archive/1992/1992-07-cb.pdf

Check page 10 and 11.

[ThomasPowers]

Quenching from red in water will: do nothing; or harden it and make it very brittle requiring tempering to make it tough; or shatter it: depending on alloy---it may be an oil hardening steel or even air hardening.

Please review the BP on heat treating!

The pre-drill heat and punch should work well for that size I might use a auto valve for the punch material (making sure it's not a sodium filled one first of course!)

[M. Demetrius]

For hobnails, hardening isn't really desirable. They'll outlast the leather in the shoes, no matter what (except for the ones that disappear because they weren't clinched properly--which requires softer metal. I'd think and ash bucket to drop them in might be the way to go, but hey, what do I know?

Let 'em be soft, says I. The cones are still harder than dirt, y'know.