Sand casting for large or low-volume metal parts.

Gray and ductile iron, cast steel, aluminum and bronze poured into sand molds — the low-tooling route to big, robust or short-run castings, machined to final tolerance in-house.

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Quick definition

Sand casting packs bonded sand around a reusable pattern to form a mold, pours in molten metal, then breaks the mold to release each part. Because the pattern is far cheaper than a steel die, it is the process for large parts, heavy sections and low-to-medium volumes — in iron, steel, aluminum or bronze — machined afterward to the tolerances that matter.

Poured into sandBig, robust, low tooling
IronEN-GJL / GJSDamping · strength
SteelCarbon/alloyHigh load
Al / BronzeAl · CuSnLight · bearing
Machined to final tolerance after casting — one quote.
4 metal familiesiron, steel, aluminum and bronze, poured to suit the job
Low toolinga wood or resin pattern, not a hardened steel die
Grams → tonnesfrom a small bracket to a casting of several hundred kilos
Machined to specas-cast surfaces finished to tolerance in-house

Cast and machined, not just poured

A rough casting still needs a machine shop.

A foundry pours the metal and stops there — you get a raw, over-thick casting with as-cast tolerances and a machining allowance you have to farm out. OperGo casts the part, then machines the faces, bores and threads to spec in-house, so it arrives ready to fit — not a rough part waiting on a second vendor.

Raw casting, machined elsewhere
  • Metal chosen by the foundry, not by the part's load or wear
  • As-cast tolerances, with the machining left to you
  • Machining allowance guessed, then re-quoted after casting
  • A separate shop, account and lead time for the finishing
The OperGo way
  • Iron, steel, aluminum or bronze matched to strength, wear or weight
  • Cast, then CNC-machined to final tolerance under one quote
  • Machining stock designed in from the pattern stage
  • One team and one account from pattern to finished part

What we run

Four metals, poured and then machined.

Iron castings

Gray iron (EN-GJL) for vibration damping and cost, ductile/nodular iron (EN-GJS) for strength and impact — housings, brackets, pump and machine bodies.

Steel castings

Cast carbon and low-alloy steel where the part has to carry real structural or wear load.

Aluminum sand casting

Light castings for housings and covers, in low volumes where a die isn't justified.

Bronze & pattern-making

Bearing and bushing bronzes, plus in-house pattern-making and post-cast machining to final tolerance.

The spec sheet

Metals, sizes and tooling.

Metals & tooling · Sand Castingmachined to spec
Cast ironGray iron (EN-GJL / GG) for vibration damping and low cost; ductile/nodular iron (EN-GJS / GGG) for tensile strength and impact resistance.
Cast steelCarbon and low-alloy cast steels for high-load structural and wear parts.
Non-ferrousAluminum casting alloys for light housings, and bronzes/brasses for bearings, bushings and marine parts.
Size & toleranceFrom a few hundred grams to castings of several hundred kilos; as-cast tolerances tightened by machining on functional faces and bores.
ToolingA wood, resin or metal pattern — far cheaper than a steel die, which is what makes low volumes and large parts economic.

Full range of materials and finishes on Materials & finishes →

Picking a process

Sand casting wins on size and low volume — die casting wins at scale.

Sand casting vs. die casting →

Die casting suits smaller, thin-walled parts in high volume, where a steel die pays off. Sand casting suits large or heavy parts and low-to-medium runs, where a cheap pattern beats expensive tooling.

Sand casting vs. CNC from billet →

For a big, bulky metal part, casting near net shape and machining only the functional faces is far cheaper than cutting the whole thing from solid stock.

Finished, not just poured →

We machine the bores, faces and threads that need tolerance after casting, so the part arrives ready to assemble — not a raw casting to farm out.

Sand casting, answered

When is sand casting cheaper than die casting?

When volumes are low to medium, or the part is large or heavy. Sand casting only needs a pattern — a fraction of the cost of a hardened steel die — so it wins whenever you can't spread that die cost over a big run, or the part is simply too big to die-cast.

How big a part can you cast?

From small brackets of a few hundred grams up to castings weighing several hundred kilos. Size is one of sand casting's advantages — it handles heavy sections that die casting and machining-from-billet can't reach economically.

What tolerances can I expect — do I need machining?

As-cast surfaces are relatively loose by design. We add machining stock from the pattern stage and CNC-machine the faces, bores and threads that need real tolerance in-house, so the finished part fits — you do not get a raw casting to farm out.

Gray iron or ductile iron?

Gray iron damps vibration and is cheap, ideal for machine bases, housings and brackets. Ductile (nodular) iron adds tensile strength and impact resistance for parts that carry load or take shocks. We pick by what the part has to survive.

What does the pattern cost and who makes it?

A pattern in wood, resin or metal is a one-time cost, much lower than a die, made in-house. It is reused for the whole run and stored for repeats, so re-orders skip the tooling step.

What if sand casting isn't right for my part?

Your engineer will say so at quoting — a small, thin-walled, high-volume part is better die-cast, and a precise one-off is better machined. Opening this page doesn't commit you to a process.

Sand casting vs. die casting →

Large parts at low tooling cost vs. thin-walled parts at volume.

CNC Machining →

The finishing step that brings a casting to final tolerance.

See all capabilities →

CNC, injection molding, casting and everything else we run.

Materials × process

Materials we run in sand casting.

Sourced, produced and finished under one quote. Tap a material to see the other processes it runs on — material and process are two axes you combine, not one nested inside the other.

SteelAluminumAll materials & finishes →

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