Core line, represented 25+ years

Screw machine products

Screw machining is high-volume turning of small parts from bar stock on cam-driven or CNC multi-spindle and Swiss-type screw machines. It makes pins, bushings, fittings, fasteners, and shafts from under 0.040 in (1 mm) to about 2.5 in (64 mm) in diameter, with cycle times measured in seconds and diameters commonly held to ±0.001 in (±0.025 mm).

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Where it pays off

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At a glance

Cam multi-spindle setups take hours, so they pay back on long runs. CNC Swiss machines are competitive from about 1,000 parts.

Diameter range: About 0.020–1.25 in (0.5–32 mm) on Swiss; up to about 2.5 in (64 mm) on multi-spindle
Typical tolerance: ±0.001 in (±0.025 mm) standard; ±0.0002–0.0005 in (±0.005–0.013 mm) on critical diameters
Concentricity: About 0.0005–0.001 in (0.013–0.025 mm) TIR on features cut in one chucking
Surface finish: Ra 32–63 µin (0.8–1.6 µm) as turned; 16 µin (0.4 µm) or better with finishing
Length-to-diameter: Swiss handles slender parts over 10:1
Cycle time: Typically 5–90 seconds per part
Bar stock: Round, hex, and square bar in 12 ft (3.7 m) lengths
Tooling cost: Form tools and cams typically $500–$5,000 per job; CNC Swiss needs little dedicated tooling

Lead time

Tooling: 1–4 weeks for form tools and cams
First article: 1–3 weeks
Production: 3–6 weeks per release

What would it cost?

The builder's estimator on a representative turned shaft. Change a size, the quantity or the material and the price updates.

All-in price per part (tooling and setup amortized) by order quantity. Budgetary.

Turned shaft · Screw machining

$1.48per part, all-in, at 10,000 pcs

Order total $14,757

Tooling: $1,800; one-time, spread over the order
Piece price: $1.17; before setup + tooling
Lead time: 4–6 weeks; to first production

Size

Drag a row to adjust · click to type

Major diameter

16.0

Overall length

60.0

Step diameter

10.0

Material

Design checks pass

Open in builder

Budgetary estimate for a representative part. Firm quotes come from principals after drawing review.

How does it work?

5 steps from drawing to production parts.

1
Bar selection
Bar stock, often free-machining 12L14 steel, C360 brass, or 303 stainless, is ordered in 12 ft (3.7 m) lengths at the needed diameter and shape.
2
Tooling and setup
Form tools, drills, and threading tools are set at each spindle position, with cams or CNC programs controlling the motion. Multi-spindle setups can take a full shift.
3
Machining
Bar feeds through the spindle while tools turn, drill, form, thread, and knurl in sequence. On multi-spindle machines every spindle cuts at once and one part finishes per index.
4
Cutoff and back-end work
Finished parts are cut from the bar. Cross holes, slots, or back-end features are added on a secondary spindle or in a second operation.
5
Cleaning, inspection, and finishing
Parts are washed of cutting oil, checked by SPC sampling, and heat treated or plated as required.

When is screw machining the right call?

Best for

Pins, shafts, bushings, spacers, and standoffs
Hydraulic and pneumatic fittings and valve components
Custom fasteners and threaded inserts
Long, slender, precise parts on Swiss machines
Runs from 5,000 to millions of turned parts

Pick something else when

Prismatic or milling-heavy parts: use CNC machining
Runs under about 1,000 parts or larger diameters: CNC turning centers set up faster
Gears and non-round profiles at high volume: powdered metal may cost less

Materials

12 materials principals run in screw machining. Pick one for design rules, finishes and an estimate in that material.

Design rules that keep the price down

Full screw machining design guide Swiss turning

12L14, 1215, C360 brass, 303 stainless
Use free-machining alloys
Free-machining grades break chips cleanly and allow faster feeds, cutting cycle time.
Set the largest OD at a standard bar size, such as 0.500 or 0.750 in
Design to stock bar sizes
Turning down from the next size up adds cycle time and scrap.
Inside corner radius of 0.005–0.015 in (0.13–0.38 mm)
Allow a tool nose radius
Sharp internal corners need special tools and concentrate stress.
No more than about 6× diameter
Limit drilled hole depth
Deeper holes need peck cycles or gun drilling and slow the cycle.
Allow at least 2 thread pitches of relief or runout
Provide thread runout
Threading tools need room to exit without a special undercut.
0.010–0.020 in × 45°
Chamfer edges
Chamfers deburr on the machine and ease assembly.
Expect 0.0005–0.001 in TIR within one chucking
Hold concentric features in one setup
Re-chucking for a second operation loses concentricity.
Default to ±0.001 in or looser on non-critical diameters
Tolerance only what matters
Tighter limits add grinding or inspection to every part.

What drives the cost?

In order of impact.

1
Material
On small turned parts, bar stock is often the largest cost. Free-machining 12L14 and C360 brass cut fastest; stainless and titanium cut slower and cost more per pound.
2
Cycle time
Every second on the machine counts at volume. Features that need extra tools or slower speeds add directly to piece price.
3
Setup and run length
Multi-spindle setups can take a full shift. Longer runs spread that setup across more parts.
4
Tolerance and finish
Holding ±0.0002 in instead of ±0.001 in may add grinding, slower feeds, or 100% inspection.
5
Secondary operations
Cross drilling, milled flats, heat treating, and plating add handling unless they are done on the machine.

Variants

Cam-driven multi-spindle: Classic Davenport, Acme-Gridley, and similar machines run 4–8 spindles at once for the lowest cost per part on very long runs.
CNC multi-spindle: Servo-controlled multi-spindle machines keep multi-spindle output with faster setups and tighter process control.
Swiss-type (sliding headstock): The bar slides through a guide bushing so every cut happens close to support. Ideal for long, slender, precise parts.
Single-spindle automatics and bar-fed CNC lathes: Faster changeovers for shorter runs and larger diameters.

Where it shows up

Go deeper

Screw machining: multi-spindle vs Swiss vs CNC lathe5 min
How multi-spindle, Swiss-type, and CNC turret lathes compare on volume, tolerance, and setup, plus the materials, tolerances, and design choices that set cost.

Screw machining questions

What is the difference between Swiss and multi-spindle screw machines?

Swiss machines support the bar in a guide bushing next to the cut, so they excel at long, slender, tight-tolerance parts up to about 1.25 in (32 mm) diameter. Multi-spindle machines cut 4–8 parts at once and win on cost for high-volume, shorter parts up to about 2.5 in (64 mm).

What tolerances can screw machines hold?

Standard turned diameters commonly hold ±0.001 in (±0.025 mm). Swiss machines with in-process gauging reach ±0.0002–0.0005 in (±0.005–0.013 mm) on critical diameters. Tighter work usually adds centerless grinding.

What is the minimum order for screw machine parts?

CNC Swiss work is often practical from about 1,000 pieces. Cam multi-spindle jobs usually need 10,000 or more to justify setup. Many shops quote a minimum lot charge instead of a strict piece count.

Can I still use 12L14 leaded steel?

12L14 contains lead, which gives excellent machinability. Leaded machining steel is covered by a RoHS exemption, but some customers ban it outright, so 1215 is the common lead-free substitute.

How long does it take to get screw machine parts?

Production typically ships in 3–6 weeks, depending on bar availability and machine loading. First articles often ship in 1–3 weeks when material is in stock.

Should I choose screw machining or CNC turning?

Choose screw machining for small-diameter parts at high volume, where cycle time dominates cost. Choose CNC turning for lower volumes, larger diameters, or designs that change often, where setup time dominates.

Quote screw machining today.

Drop a STEP file for an instant estimate and DFM check. A rep routes the RFQ to principals who run this process every day.

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Screw machine products

Where it pays off

1101001k10k100k1M+