The heat inside the blacksmith foundry was a roaring fire wall that pushed back the sub-zero chill of the frontier night.
At the center of the earthen floor, the improved charcoal hearth burned with a blinding white-yellow bright glare.
Twin leather bellows, pumped by two muscular High Timber exiles swinging from overhead balance levers, groaned rhythmically.
Whoosh. Clack. Whoosh. Clack.
Borin the smith stood before the hearth, his bare torso glistening with sweat despite the arctic cold seeping under the door sills.
His leather apron was charred black around the hems, and heavy iron tongs rested in his calloused fists.
“Iron is melting down clean, Lord Giles!” Borin bellowed over the roar of the forced blast.
“Six hundred pounds of bog-iron pig! Running like cherry syrup.”
Giles Croft stood beside the casting benches, inspecting the stacked mold boxes.
Each mold box was crafted from squared pine frames holding dried heat-proof clay gang-molds.
Inside each clay slab, hundreds of ball-shaped cavities had been impressed using a bronze master-die—each cavity three-quarters of an inch in width, linked by branching sprues and feeder runners.
Douglas ran a calloused thumb along the edge of the finished pine mold flasks.
“We fitted each flask with narrowed brass locating pins, Lord Giles,” Douglas said proudly.
“When Barnaby clamps the two halves together, there is zero lateral play.
The parting line is tighter than a royal coffer.
Not a drop of molten iron will flash out between the joints.”
Giles checked the posture with his feeler gauge.
“A clean parting line eliminates mold flash.
Excess flash increases post-cast dressing labor by forty percent.
Care in the timber shop saves hours on the foundry floor.”
Toby Karr was dusting the cavities with fine graphite powder from an old leather pouch.
“Report on the heat-proof mixture, Toby,” Giles said. He tapped the edge of a mold with his wooden rule.
“Did Barnaby use raw river clay or the fired grog blend?”
“The grog blend, Lord Giles.” Toby answered quickly, wiping sweat and black dust from his forehead.
“Sixty percent fireclay, thirty percent crushed firebrick grog, and ten percent washed quartz sand.
We baked them in the drying oven for six hours to drive out all bound moisture.”
Giles nodded with satisfaction.
The first gang-mold prototype they had poured two days earlier had failed disastrously.
Barnaby had used damp river silt to save time.
The twenty-four-hundred-degree molten iron struck the green sand. Then, the trapped moisture flashed wildly into white-hot steam.
The mold had blew up with a sharp crack, spraying droplets of liquid iron across the foundry ceiling and ruining fifty pounds of metal.
Barnaby had burned his forearm, and Borin had cursed the river clay for two hours.
Giles had right away halted production, redesigning the mold matrix with calcined heat-proof grog and venting grooves along every parting line.
“The vents are the lifeblood of gravity casting,” Giles reminded Toby.
“Gas spreading follows Boyle’s law.
If steam and carbon monoxide can’t escape through the grog pores, the iron bubbles into spongy melted rock waste with zero fragmentation mass.
We need solid, unpitted iron pellets with high sectional thickness.”
Giles dipped an iron sampling spoon into the white-hot crucible, scooping out a small puddle of molten metal and pouring it onto a flat scrap of metamorphic slate.
The iron spread into a gleaming silver button, cooling rapidly from cherry-red to dull gray.
Giles struck the edge of the test button with a small brass hammer.
The bead fractured cleanly, revealing a fine, sparkling crystal-clear structure with zero visible gas bubbles.
“Carbon content is sitting at three point eight percent,” Giles noted, examining the fracture under his magnifying glass.
“Silicon is about two point one percent.
That ratio provides optimal fluid thickness to fill our three-quarter-inch ball-shaped cavities without cold-shuts or internal void shrinkage.
The bog ore from the lower reed marsh has paid dividends.”
Borin wiped a sleeve across his sweating brow, grinning through his soot.
“We roasted forty tons of that bog muck in the clamp kilns to burn out the sulfur, Lord Giles,” Borin grunted.
“Hardest digging of my life, but the iron runs sweet as clover honey.”
Barnaby stepped up with an iron skimmer rod. He dragged a thick crust of gray quartz dust waste scum off the surface of the glowing crucible.
Beneath the melted rock waste, the molten metal shone like liquid sunlight.
“She’s ready to pour, Lord Giles!” Barnaby yelled.
“Hoist the ladle.”
Four men threw their weight onto the chain fall.
The massive graphite crucible rose from the charcoal bed, tilting forward into the heavy double-handled pouring shank.
Borin gripped the master handle, his face set in grim determination.
Giles stood at the head of the casting line, checking the posture of the gang-molds.
Beside each mold box sat a fifty-gallon wooden trough filled with freezing salt water from the salting sheds, crusted with floating ice shards.
“Pour on my mark,” Giles commanded.
“Steady pour rate. Fill the central sprue to maintain high-pressure head pressure.”
Borin tilted the shank.
A stream of blazing bright white liquid iron poured into the funnel of the first mold box.
The iron flowed down the runner channels, filling eighty ball-shaped cavities in a split second.
Tiny jets of pale blue carbon monoxide ignited at the vent holes. It hissed softly against the dark ceiling beams.
There was no explosion, no violent popping of steam.
The dry grog clay held perfectly.
Within twenty seconds of the pour, Giles signaled with his hand.
“Strip the mold! Chill-cool right away.”
Barnaby and Douglas knocked the iron wedges from the mold clamps with heavy sledgehammers.
The split clay halves fell apart. It exposed clusters of cherry-red iron spheres hanging from their central sprues like fiery bunches of grapes.
Borin used long-nosed iron tongs. He seized the glowing clusters and plunged them directly into the icy salt water trough.
CRACKLE-HSSSSSSSS!
A violent cloud of salty steam billowed into the foundry rafters.
The salt water boiled instantly around the iron, spitting white foam across the workshop floor.
“Why freeze them so fast, Lord Giles?” Toby asked, coughing into his sleeve as he watched the steaming tank.
“Doesn’t sudden cooling make the iron brittle?”
“That’s exactly the heat-powered objective,” Giles explained, picking up a cooling iron pellet with tongs.
“Slow air cooling allows carbon to precipitate out as soft flake graphite, producing gray iron that deforms on impact.
Sudden salt water cooling freezes the carbon into solution, transforming the outer layer into white iron with a martensitic crystal structure.
It creates a surface hardness exceeding sixty Rockwell C.
When the ward-pad detonates, these pellets won’t flatten or deform against crystal-clear beast armor.
They will strike like armor-piercing chisel points, punching clean through bone and ice.”
Borin hauled the iron cluster from the salt water with an iron hook, dumping it onto the heavy steel anvil block.
He picked up a heavy cold file and dragged it hard across the dark gray surface of an iron pellet.
Skrrt!
The hardened steel file teeth skittered off the ball with a high-pitched screech. That left not a scratch on the burnished metal.
Borin let out a thunderous belly laugh that rattled the hanging tools.
“Harder than a miser’s heart!” Borin roared.
He raised a five-pound hand hammer and struck the central runner with a ringing blow.
CLANG.
The brittle sprues shattered instantly.
A pouring hail of hundreds of smooth, blue-black iron balls cascaded across the assembly table with an ear-splitting metal roar.
Borin picked one up, rolling the hardened sphere between his calloused fingers.
A fierce, manic grin split his soot-blackened face.
“Hard as diamonds, round as royal ducats!” Borin bellowed, slamming his fist onto the timber table.
“Pack them into the ward-pads, boy!
Give those frost-monsters forty pounds of cold iron to chew on.”
Toby scrambled to the assembly bench, scooping the chilled iron balls into wooden measuring buckets.
At the packing table, Millicent and Rowena were setting the pellets into the curved oak casings of the Directional Shrapnel Ward-Pads.
Behind each concave layer of eight hundred iron pellets lay a thick wadding of animal fat-soaked felt. It was backed by thirty pounds of tightly packed blasting powder and Giles’s ringing mana-primer coils.
Millicent weighed the powder charges on the brass scale with exact care.
“Thirty pounds of grain powder per box,” Millicent stated. He poured the black granules through a copper funnel.
“Tamped to two pounds of pressure thickness.
Every ounce is logged against our defensive munition ledger.”
Toby tamped the animal fat wadding with a wooden mallet, his fingers moving with wild speed.
“That’s box number eleven filled.” Toby shouted.
“Box number twelve is taking the last four hundred bearings.”
Millicent tied off the waterproof canvas cover over the twelfth warhead, dipping her pen to check the box on her munitions ledger.
“Twelve ward-pads sealed and checked,” Millicent said with crisp smooth speed.
“Nine thousand six hundred chilled iron bearings in total.
Every unit has its primer well greased against frost.”
Millicent dipped her pen, making a final proof mark on her ledger sheet.
“Each completed ward-pad contains thirty pounds of black blasting powder and twenty-five pounds of chilled iron bearings,” Millicent explained to Kenneth Drake as he watched the packing.
“In the capital armories, a royal ordnance builder would charge forty silver marks per mine.
Here on the frontier, using our own charcoal, dredged bog iron, and local sulfur, our unit production cost is less than three silver shillings.
House Croft produces military munitions at an eighty-five percent discount compared to royal procurement rates.”
Kenneth rubbed his chin, looking at the stacked cases with deep respect.
“An army that can forge its own artillery shot out of ditch mud,” Kenneth muttered, “is an army that never runs out of teeth.”
Kenneth Drake entered the foundry, snow blowing in around his boots as he shoved the heavy oak door shut.
He looked at the mountain of gleaming iron pellets covering the table, then glanced at Giles.
“The wolves are moving down the scree hall,” Kenneth said in a low, urgent tone.
“The vanguard has crossed the five-hundred-yard contour line.
We have less than forty minutes before they reach the tripwire zone.”
Giles checked his pocket watch, then nodded to the packing crew.
“Load the twelve ward-pads onto hand sleds,” Giles ordered.
“Bring the iron ground-stakes and the copper deep ring wire.
We deploy the outer edge web now.”
Borin wiped the soot from his eyes, picking up his five-pound hammer.
“I’ll carry the stakes, Lord Giles.
If any wolf gets past these iron balls, I’ll crack its skull on the anvil.”