EMAP_2012_Report_6_1.pdf (7.3 MB) - The Heritage Council

2.4.1: Smithing
Secondary smithing (blacksmithing) or forging was then undertaken on the billet to produce
or repair metal objects. The metal was heated in a hearth before hand tools and an anvil
were used to shape it into the desired object form (Carlin 2008, 94). A range of smithing
processes could be undertaken from forging, to plate or bar, artefact manufacture and repair
(Young 2010, 8.1). Iron-smithing can be done in most places even at a domestic hearth and
does not require a purpose-built structure (Wallace and Anguilano 2010b, 71). Evidence for
all these processes can be present in the form of features such as smithing hearths, ceramic
tuyères, metallurgical smithing waste and other features such as anvils and a range of
artefacts used in the manufacturing process. A total of 15 settlements with 51 smithing
hearths have been recorded within the EMAP 2012 gazetteer which had available specialist
reports (Appendix 1).
The morphology of smithing hearths is becoming clearer through a wide range of recently
excavated examples (Table 2.2). In commentary on smithing hearths Young notes that subrectangular
or circular hearths of 0.8 in diameter would be small for blacksmithing but that
bloomsmithing may not have required the same size (Young 2008, 4). He notes that bloom
smithing hearths are poorly known. Young in a discussion of 23 Irish smithing hearths, mostly
of early medieval date suggests that they vary from equidimensional in plan through to
having a long axis up to 1.5 x the short axis (Young 2009b, 236). A number of smithing
hearths were discovered along the route of the M4 at Rossan 4, Hardwood 3, Newcastle 2
and the majority of these had a distinctive rectangular plan with steep sides and a flat base.
Most of these smithing hearths were 1-1.6m long and 0.1-0.4m deep and were used for
bloomsmithing, i.e. the refining of iron bloom into billet (Carlin 2008, 100). Photos-Jones
states that hearths associated with metallurgical waste of 1.2 – 2.5m in size cannot be
associated with smelting and must have been used for smithing (Photos-Jones 2008a, 194).
She suggests that the hearths identified at Killlickaweeny and Johnstown were associated
with the bloomsmithing process. Some sites such as Two-Mile Borris had evidence for up to
six smithing hearths of different dates one of which was located close to a large consolidated
iron bloom (Wallace and Anguilano 2010b, 81).
However, primary smithing may have been undertaken at the smelting site and the furnace
pit was occasionally used as a hearth. Iron smelting furnaces inside Structure G at Reask
appears to have been deliberately dismantled, but later re-used for iron smithing or copperalloy
melting (Fanning 1981, 108–10). Some smithing hearths may have had low clay
superstructures which would have contained blow-holes for connecting bellows. Some sites
have revealed the remains of smithing hearths which have been discarded. A flat stone with
slag and clay adhering was identified as the base of a smithing hearth within the enclosure
ditch at Parnahown, County Laois (Young 2009c, 6).
Stone lined smithing hearths were found at Gortnahown 2 and Park 1(Young 2011b, 124).
The latter was at the base of one hollow within a figure-of-eight structure and associated
with hammerscale.
Smithing hearths cannot be definitively identified without analysis of associated metallurgical
residues. Many sites do not have smithing hearths within the excavated area but analysis of
metallurgical residue suggests smithing was carried out at that site. EMAP identifies at least
16 sites within the sample which did not have a hearth but where archaeometallurgical
analysis indicated smithing.
The presence of smithing on a site can be indicated by the presence of particular types of
metallurgical waste. The slag would accumulate at the base of the pit to form the distinctive
plano-convex lumps of waste, known either as hearth bottoms or cakes (Carlin 2008, 94).
The size and chemical composition of these can indicate what kind of smithing process was
being carried out. Smithing hearth cakes from refining are generally heavier than those
generated by secondary smithing but this can vary (Wallace & Angiulano 2010, 5). Smithing
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