Thank you for your fascinating comments, I'm learning a lot! The hole at the top of the anvil is (now) more of an oval measuring 17mm x 13mm so the nail head would have had to be quite large not to fall through. Are we saying the main square shafted nail would first be hammered out into shape on the anvil's face leaving a thickened end and then slotted into the hole and hit with a hammer to make the nail head before being knocked out from below or the side to release it?

Would that diameter hole be large enough to hold tools in the fashion of the hardie hole? It sounds a useful multi-functional piece of kit if one hole serves as a hardie/pritchel/nail header hole.

Thank you Kozzy for the description of sponge iron.

Nowadays most folks use a separate nail header and just use the pritchel hole to place the header over so the nail shaft can stick down but the header is supported. I don't know the Roman methods of heading.

Dear Linz,

I am assuming that there are You Tube videos of mail making since there are videos of everything else.  I will describe how I make nails so that you have an idea of how it works.  I don't make nails often because I once took an order for 500 and since then nail making is not fun for me.  First, you need a nail header which has one or more square tapered holes in it. (The taper is from the bottom up. That is, the hole is slightly wider at the bottom than the top.  This is so the nail is less likely to stick in the header.)  The nail header is a separate hand held piece of steel.  The nail is made by heating a square piece of stock and then hammering a point on it.  This is usually done on the edge of the anvil so that there is a shoulder at the end of the tapered point.  Without a shoulder there is a tendency just to hammer the nail through the hole of the header rather than upsetting the head.  The nail is then cut off the stock a bit above the shoulder.  This is often done with a hot cutter set in the hardie hole.  Usually, the nail is not completely cut off so that the nail can be inserted into the header and the rest of the stock can be  twisted off leaving the nail in the header with the un-upset head above the header.  Then the nail head is flattened down on the header.  Finally, the nail is knocked out of the header either by inverting the header and banging it on the edge of the anvil or tapping it out from the bottom with a hammer.  If you are good and have the right muscle memory you can do this in one, or at most two, heats.  It is harder to describe than actually do.

I still think that it is unlikely that the hole in the anvil was intended to be primarily a nail of spike header.

""By hammer and hand all arts do stand."