Custom Spun Hemispheres for Tanks & Domes

Metal Craft Spinning produces custom spun hemispheres from steel, stainless steel and aluminum. Our metal spinning process forms seamless, one-piece hemispheres from flat metal blanks — no welding seams, no joints, and no weak points. Hemispheres are available from 12″ to 36″ in diameter with custom wall thicknesses to match your application.

What Are Spun Hemispheres and How Are They Made?

A spun hemisphere is a half-sphere shape formed from a flat sheet metal disc through the metal spinning process. The metal blank is clamped to a spinning lathe and pressed over a shaped mandrel using CNC-controlled rollers. As the lathe rotates, the sheet metal flows smoothly into a hemispherical or spherical form — producing a seamless part with uniform wall thickness.

Metal spinning is a cold-forming process similar to rolling, where the metal is shaped at room temperature without melting or casting. This preserves the material’s grain structure and mechanical properties. The result is a stronger, more consistent product than welded or fabricated alternatives.

For hemispheres, spinning offers clear advantages over stamping and deep drawing. Tooling costs are significantly lower because spinning uses a single mandrel rather than matched die sets. Design changes are faster — modifying a mandrel is simpler and cheaper than re-cutting stamping dies. And spinning handles low-to-medium production volumes economically, where stamping only becomes cost-effective at high volumes.

Metal Craft Spinning runs CNC spinning equipment including Nova Sidera machines, giving us programmable control over every forming pass. CNC metal spinning delivers repeatable tolerances and consistent wall thickness across production runs.

Materials and Sizes

We spin hemispheres in a range of metals to suit different environments and performance requirements:

• Steel — mild and carbon steel for general-purpose tank heads, caps, and structural parts
• Stainless steel — 304 and 316 grades for corrosion resistance in chemical, food, and marine applications
• Aluminum — lightweight hemispheres for aerospace, lighting, and architectural uses

Hemisphere diameters range from 12″ to 36″. Custom wall thicknesses are available based on material and application requirements. For specialty alloys or sizes outside our standard range, contact us to discuss your project.

Applications for Spun Metal Hemispheres

Spun hemispheres serve a wide range of industries where a seamless, precision-formed half-sphere is required.

• Tank heads and ends — hemispheres are used as end caps for pressure vessels, storage tanks, and process equipment. The seamless construction eliminates weld points that can become failure points under pressure.
• Domes and caps — architectural domes, equipment covers, antenna housings, and protective caps. Spun domes maintain a smooth, uniform surface finish.
• Full spheres — two hemispheres which can be welded at the equator to create hollow spheres for floats, decorative spheres, tank components, and signage elements.
• Cones and conical transitions — hemispheres are often paired with spun cones or cylindrical sections in tank assemblies and industrial fabrication.
• Specialty components — lighting reflectors, fire pit bowls, fountain features, baking molds, and custom architectural metalwork.

Industries served include chemical manufacturing, food and beverage processing, oil and gas, power generation, marine, defense, architecture, and general industrial fabrication.

Custom Hemisphere Capabilities at Metal Craft Spinning

Metal Craft Spinning has produced custom metal spun products since 1964. Our facility in Buffalo, NY handles hemisphere manufacturing from sheet metal blank to finished part under one roof.

Secondary Operations and Finishing

Beyond spinning, we provide the secondary operations needed to deliver a complete, ready-to-install hemisphere:

• Trimming and shearing — precision edge finishing to final dimensions
• Beading and flanging — rolled edges and flanges for assembly and sealing
• 5-axis laser cutting — holes, slots, and custom features cut with precision after forming
• Surface finishing — painting, powder coating, plating, and anodizing

Every hemisphere is inspected for dimensional accuracy, wall thickness uniformity, and surface quality. Material certifications and traceability are available for applications that require documented material provenance.

Get a Quote on Custom Spun Hemispheres

Metal Craft Spinning produces custom metal spun hemispheres in steel, stainless steel, and aluminum from 3″ to 36″ in diameter. Whether you need tank head caps, architectural domes, or hollow spherical components, we handle the full process from flat blank to finished part. Contact us to discuss your project and request a quote.