
Casting a Bronze Socketed Spearhead — Bivalve Mould Method
The socketed spearhead was a major advance over the flat tanged point — the hollow socket allowed the shaft to be inserted directly into the head, creating a stronger and more aerodynamic weapon. This design appeared across the Bronze Age world from approximately 2000 BCE and remained in use for over a thousand years.
Creating the socket requires a bivalve mould with a clay core inserted between the two stone halves. The core occupies the space where the socket will be, so when the bronze solidifies around it and the core is broken out, a hollow tube remains. This is one of the earliest examples of core-casting — a technique that later evolved into the lost-wax process for complex hollow sculptures.
The leaf-shaped blade is cast with a raised midrib for rigidity, then the edges are cold-hammered and ground sharp. Two small holes at the socket base allow a pin or binding to lock the shaft in place.
Instructions
Prepare the bivalve mould
Prepare the bivalve mould
Materials for this step:
Soapstone Block (Steatite)2 piecesForm the clay core for the socket
Form the clay core for the socket
Materials for this step:
Refractory Clay200 g
Fine Sand100 gAssemble the mould with core
Assemble the mould with core
Materials for this step:
Rawhide Strips1 mPre-heat the assembled mould
Pre-heat the assembled mould
Melt and pour the bronze
Melt and pour the bronze
Materials for this step:
Charcoal4 kgTools needed:
Crucible Tongs (long-handled)Cool and separate the mould halves
Cool and separate the mould halves
Remove the clay core
Remove the clay core
Tools needed:
Antler TineRemove sprue and grind the parting line
Remove sprue and grind the parting line
Materials for this step:
Sandstone (Abrasive)1 pieceCold-hammer and sharpen the blade edges
Cold-hammer and sharpen the blade edges
Materials for this step:
Whetstone1 pieceTools needed:
Hammerstone
Flat Stone SlabDrill the rivet holes and haft
Drill the rivet holes and haft
Materials
7- 2 piecesPlaceholder
- 200 gPlaceholder
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- 1 piecePlaceholder
Tools Required
4- Placeholder
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