Wednesday, June 03, 2015

Viking Age Padlock

I had been contacted a while back by a fellow re-enactor of the Viking Age who undertakes presentations at a major Medieval / Renaissance Festival in the USA. He has a security problem (sounds like absolutely huge crowds!). He has ordered a pair of Norse era padlocks, with the associated strap hinge and hasp assemblies to fit on to sea chests.

This is the reference image he had sourced (off the internet):
So - here is the first problem. The internet as source.

The image is actually taken from (and not credited to) Anglo-Scandinavian Ironwork from Coppergate by Patrick Ottaway.

Like usual for a replica project like this one, I checked my own reference library. A second source I checked was Ironwork in Medieval Britian by Ian Goodall. Both are primary sources - as they are first generation archaeological reports. They include the original detailed scale drawings of the objects listed (but neither has photographs).
There are a couple of possible configurations of the basic 'compress a spring' mechanism in barrel padlocks. (There is an alternate construction method - the box padlock.)
These are split between cases with a hole in the end plate that use a fork, and those with a key rectangular hole in the end. An alternative is a case with a T shaped slot along the lower edge, also using a key with a shaped hole in it.

Goodall illustrates a number of barrel padlocks. However almost all are post 1100.  Almost all are also of the T slot type. There is one that fits the mechanism type and date requirements : # 16 - Winchester, Hampshire, c 1100. Unfortunately the scale of the illustration (roughly 1:3) is too small to show much detail.

Ottaway reports that at Coppergate there was only one complete barrel padlock found, plus two other case fragments.

Direct scan from Anglo-Scandinavian Ironwork from Coppergate
My normal practice is to take a scan of the artifact image, then run it through Photoshop to increase the image to life sized.  This allows me to take direct measurements right off the illustration, and most certainly helps with getting proportions and shapes more accurately.

First consideration for me - the customer has NOT asked for a direct reproduction / replica of this specific object. The artifact is highly ornamented - and I certainly did not quote a price for this level of decoration.
Second 'problem' is that the customer's source is * not actually an artifact *. That reference drawing is only a * diagram * - meant to illustrate the function of the lock mechanism.

What we see from the actual artifact (#3610):
case diameter = 4.5 cm / 1 3/4 inch
case length = 7 cm / 2 3/4 inch
metal thickness = 3 mm / about 1/8 inch
upper cylinder ID = 8 mm / 5/16 inch (suggests upper bar diameter at 6 mm / 1/4 inch)

Next Post : Forging materials to dimension

Regular Readers - may notice there has been a big gap in postings. Early May I attended the International Medieval Studies Conference for a week. On arriving back to Wareham, we found our satellite uplink hardware no longer receiving a signal. Through various failures, it was May 29 until internet access was restored here.

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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