Capability

Machining

Turned parts where forming cannot reach

CNC turningShoulder screwsInserts & standoffsStepped pins

Turned shoulder screws with ground shanks

Machining · Bekasi plant

Process overview

Turned parts where forming cannot reach

Cold forming is fast and strong, but it cannot produce every geometry. A stepped pin with two diameters, a standoff with a through thread and a square body, or a shoulder screw with a ground shank all start from bar and are turned. Machining is the route for parts whose shape or quantity does not justify a die.

Machining is also where the cost conversation usually starts. A part that is turned can often be redesigned for cold forming once volume justifies a die, and that change is one of the most effective cost reductions available on a fastener — the process converts a cutting operation into a forming one and removes the material waste at the same time. We review turned parts for that possibility rather than continuing to machine them indefinitely.

Step by step

How the process runs

Each step has a defined control point. The sequence is not arbitrary — changing it changes the result.

Drawing review

The part is reviewed for what turning can hold and whether a formed alternative would be cheaper at volume.

Bar selection

Bar stock is selected for the grade and diameter, with the material certificate retained against the lot.

Turning

CNC turning produces the primary diameters, faces, threads and grooves in one or more operations.

Secondary operations

Grinding, thread milling or slotting where the drawing requires a feature that turning cannot produce.

Deburr and finish

Parts are deburred and then passivated, plated or coated as specified.

Inspection

Critical dimensions are measured and recorded, with the report issued against the lot.

Specification

Process window and capability

The numbers below define what the process can hold repeatably. They are not laboratory bests.

Process

CNC turning from bar stock

Typical parts

Shoulder screws, standoffs, spacers, thread inserts, stepped pins, sleeves

Features

Diameters, faces, threads, grooves, slots, hex and square bodies

Secondary operations

Grinding, thread milling, slotting, deburring

Materials

Stainless steel, carbon steel, alloy steel, brass, aluminium, titanium

Finishes

Passivation, nickel, zinc, black oxide, PVD, anodising

Cost lever

Redesign for cold forming once volume justifies a die

Equipment

What the line is built on

Capacity figures are per machine and assume a standard part. Complex geometry reduces throughput.

Equipment	Specification
CNC turning	Primary and secondary turning of bar stock
Grinding	Shoulder and locating diameters where a ground surface is specified
Video measuring system	Dimensional verification of turned features

Process control

What is checked, and when

A control that is not recorded is not a control. Each item below generates a record linked to the lot code, retained for the programme duration.

Quality & certifications

Material certificate retained against the lot

First-off approval before the run continues

Critical dimensions measured with VMS or contact instruments

Thread gauge, GO / NO-GO

Surface finish checked where specified

Deburr inspection on edges and recesses

Questions

Machining FAQ

Practical questions from sourcing and engineering teams.

Considering a process change? If a tolerance or finish is not achievable on our current line, we will say so before quoting rather than after the first lot.

When should a part be machined rather than formed?

When the geometry cannot be formed — a stepped pin with two diameters, a square body, a through-threaded standoff with tight face squareness — or when the quantity is too low to justify a die. Machining is also used for development samples before a die exists.

Can a machined part be converted to cold forming?

Often yes, and it is usually the largest cost reduction available. The process replaces cutting with forming, removes material waste and shortens the cycle. It needs enough volume to amortise the die, so it is evaluated against the annual quantity rather than a single order.

How is the shoulder ground on a turned shoulder screw?

As a secondary operation after turning. Turning establishes the geometry; grinding produces the surface and roundness that a pivot actually needs, which is why a ground shank is specified separately from a turned one.

Do you supply material certificates?

Material certificates are retained against the lot and issued with the inspection report where the purchase specification requires them.

Related capabilities

What happens before and after

These processes are usually sequenced with the one above.

Precision screw family produced from in-house heading dies

Capability

Tooling & Die Shop

Heading dies and punches are designed and built in-house, so geometry can be changed during development instead of waiting for an outside toolmaker.

Capability

Cold Forging

Single- and multi-station cold heading forms the screw from wire, so the grain follows the part contour and no material is machined away.

Plated socket head screws inspected in the laboratory

Capability

Inspection Laboratory

Metallography, hardness, dimensional measurement, tensile, friction, salt spray, coating thickness and RoHS testing, all in-house so a question can be answered without waiting for an outside lab.

Need machining for your part?

Send the drawing and the annual volume. We will confirm feasibility, tolerance and lead time in the quotation.

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