Materials for Swiss screw machining need to be specified as carefully as the geometry. “Brass” or “stainless” identifies a family, but leaves the grade, condition and acceptance requirements open. For a contact pin, guide pin, sleeve or small shaft, start with its function in the assembly, then give the material designation and finished-part requirements that support that function.

Key takeaway

Keep material selection, stock condition and final acceptance connected. Specify the grade, permitted substitutions, condition, plating and documentation at enquiry stage. A published material property describes the stated alloy and condition; the part drawing and agreed manufacturing route determine what must be delivered.

01

Common Swiss screw machining materials: define the requirement first

OUJI’s micro turned-part material list covers brass, stainless steel, BeCu C17200, Kovar and phosphor bronze. The photograph shows existing brass contacts; the material sections below explain what to specify in an enquiry.

When comparing Swiss CNC machining materials, separate the component’s needs from the convenience of machining it. Does the part locate another component, carry an electrical signal, slide in a bore or form part of a sensitive interface? Identify the relevant surfaces and the environment. Give the supplier the approved material requirement rather than asking it to infer the design intent.

02

Brass: name the grade and the contact requirements

The C3604 brass production case is a published OUJI example involving 200,000 parts. Follow the linked case for the project’s machining and inspection context when preparing your own brass-part enquiry.

For your drawing, specify the brass grade and condition, the functional diameters and any plating requirement. A contact surface and a locating surface may have different acceptance needs. State whether substitutions are permitted; do not let a general material-family description stand in for an approved grade.

03

Stainless steel: grade and condition affect process planning

Outokumpu’s machining guide explains that stainless grades have different physical and thermal properties, which affect machining. “Stainless steel” therefore leaves too much open for a complete process review. Specify the grade and starting condition, alongside the required final condition.

OUJI’s SUS420J2 thin-wall case describes one documented component. For a new sleeve or shaft, identify thin walls, lightly supported features and surfaces used for fits. Make clear whether acceptance applies as machined or after a later treatment, and highlight the drawing requirements that need process review.

04

BeCu C17200: specify the temper and delivered condition

Materion identifies C17200 in its high-strength copper-beryllium range. Its published property data refer to stated material conditions, including age-hardened conditions. Naming C17200 alone does not define all of the properties expected from the delivered component.

For a BeCu enquiry, include the grade, temper or condition, and any required final hardness or material-property specification. If the drawing calls for a condition change after machining, identify that stage and the dimensions accepted afterward. Request review of the complete route, including how the delivered condition will be specified and accepted.

05

Kovar: connect material choice to the mating interface

Carpenter describes Kovar as a low-expansion iron-nickel-cobalt alloy used in glass and ceramic sealing applications. A drawing for a machined component needs to define its role within that later assembly.

For a Kovar component enquiry, state the exact material requirement, condition and geometry of the mating interface. Identify surfaces that will be used in subsequent assembly and any finish requirements there. Specify the acceptance state and documentation. Machining requirements and the performance of the assembled interface need their own clearly defined acceptance criteria.

06

Phosphor bronze: discuss strength, conductivity and stock form

The Copper Development Association’s connector design guide discusses phosphor bronze in terms of contact force, conductivity and temper. Its discussion concerns connector strip; it is useful material-selection context, not a machining specification for bar-stock parts.

Give the precise grade and condition for a turned phosphor-bronze component. Identify whether the component itself must flex or whether it is a rigid mating part in a spring assembly. Those are different design requirements. Ask for review of the required stock form and dimensions rather than treating all phosphor-bronze products as interchangeable.

07

Include plating, measurement and material documents

Gold over nickel plating is available. Specify the required finish, coating requirements, contact areas and any surfaces that must remain uncoated. Identify dimensions accepted after plating, particularly where the component mates or slides. A quotation should refer to the finished requirement, not leave the acceptance state implicit.

OUJI uses KEYENCE optical measurement. Tell us which dimensions need reporting and provide the required report format. For material certificates and traceability, state the document type, required content and lot-identification expectations so they can be reviewed with the quotation. Do not assume that a material-family name defines the documentation supplied.

OUJI operator using optical measurement equipment at the KEYENCE inspection station
Existing OUJI optical inspection photograph. The drawing defines the features and reporting scope for a new job.

08

Send the material requirement with your drawing

OUJI’s main micro turning range is Ø0.1–10 mm. Ø0.1 mm minimum diameter — feasibility depends on part length, material and features. Production batches start at 1,000 pieces; samples start at 100 pieces. Include annual volume and first-batch quantity alongside the material specification.

Review the Swiss screw machining service and its materials and plating section, then send your drawing for quotation review. The existing micro Swiss machining process article provides workshop photographs of the route from bar stock to turned parts and optical inspection.

Sources & technical references

  1. Machining guide for stainless steel — Outokumpu

    General reference for grade-specific physical and thermal properties affecting machining.

  2. High-strength copper-beryllium alloys — Materion

    Reference for C17200 and the importance of the condition stated with material-property data.

  3. Kovar alloy reference — Carpenter Technology

    Reference for alloy type and sealing applications; no OUJI assembly or sealing capability is inferred.

  4. Phosphor bronze in connector material selection — Copper Development Association

    General contact-material context based on strip; not a specification for the turned component or its stock.

  5. OUJI micro turning materials and qualified diameter range — OUJI

    Published material list and service context; quotations review the exact grade, condition and requirements.

  6. C3604 brass production case — OUJI

    Source for the brass example and its project-specific 200,000-part quantity.

  7. SUS420J2 thin-wall production case — OUJI

    Documented stainless component example; no universal grade or tolerance approval is inferred.

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