01
Cycle time on a single-turret lathe
One tool cuts at a time. A part with a face, a pilot, two grooves and a thread walks through five passes. On a 20,000-piece run that idle time turns into hours of spindle time you pay for.
Screw Machine Work
Multi Spindle Screw Machining
Several tools cut at the same time on one bar, so a turned part with six features comes off in one index instead of six passes. We run screw machine work next to our CNC turning cells for parts that repeat in the thousands.
Ø4–32 mm bar work±0.005 mm toleranceNo minimum order quantityISO 9001 / IATF 16949
15 yearsMachining screw-machine parts since 2011
127High-precision CNC machines across 3 plants
±0.005 mmRepeatable tolerance on turned diameters
99.99%Qualification rate before shipment
Where volume turning hurts
Four ways a turned part program bleeds money
If any of these sound like your last purchase order, the problem is usually the process choice, not the operator.
02
Second-op handling nobody budgeted for
Milling a flat or cross-hole after turning means a second fixture, a second setup and a second queue. Each transfer adds stack-up error and a chance to dent a finished diameter.
03
Scrap that shows up late
A bar feed drifts or a tool chips at piece 4,000. If you only check at final inspection, you find out after the whole lot is cut, not while you can still correct the offset.
04
Cost per piece that never comes down
Low-volume turning economics get quoted onto a high-volume part. Material drops are long, chip-to-chip time is short only in theory, and the unit price stays flat across the whole order.
How we cut it
Turning several tools at once, then holding the number
Two things decide whether screw machine work pays off: how the cycle is built, and how tightly the first article is locked in.
Simultaneous cutting
All tools in the cut, one index per part
A screw machine holds the bar in several positions and indexes it between stations. Each station carries its own tool, so face, turn, groove and cut-off happen in parallel rather than in sequence. For a part that would take five passes on a single-turret lathe, the cycle compresses toward the longest single operation.
That is the whole benefit. Cycle time is set by the slowest station, not the sum of all of them.
- 1Best fitTurned parts under Ø32 mm with several diameters, grooves or threads
- 2Volume thresholdSetup is fixed, so the savings grow from roughly 2,000 pieces upward
- 3Bar stockAluminium, brass, 303 and 304 stainless, 12L14 and 1215 steel
Staying on size
Cam-driven repeatability plus in-process checks
Mechanical cams repeat the same motion every index. Once the tool offsets are set, the machine does not drift the way a servo loop can over a long run. That is why screw machine parts hold ±0.005 mm on turned diameters across a full lot, not just on the first article.
We still measure. First article on a CMM, then in-process checks at set intervals, then 100% inspection before shipment with reports on request.
- 1Surface finishRa 0.8–1.6 μm as turned; Ra 0.2–0.8 μm when the geometry allows
- 2ThreadsRolled or cut, checked with go/no-go gauges each shift
- 3TraceabilityMaterial cert and inspection record tied to the lot number
Choosing the process
Which turning route fits your part
Neither column is better in the abstract. The part and the quantity decide.
| Factor | Multi spindle screw | CNC turning |
|---|---|---|
| Typical quantity | 2,000+ pieces per run | One-off to a few thousand |
| Cycle time | Tools cut in parallel | One tool at a time |
| Best geometry | Small turned parts with several features | Large or complex single parts |
| Setup effort | Higher, amortised over the run | Lower, faster to first part |
| Diameter range | Ø4–32 mm bar | Up to 4,000 mm turning length |
| Tolerance | ±0.005 mm on turned diameters | ±0.005 mm, tighter on selected features |
| Changeover cost | Justified by volume | Justified by variety |
Services
What we run alongside screw machine work
Screw machine parts rarely ship as bare turnings. These are the cells that finish them.
01
CNC Milling & Turning
Floors, cross-holes, slots and secondary features on turned blanks, without sending the part to another supplier.
02
5 Axis CNC Machining
16 simultaneous 5-axis centers for angled holes and contoured faces a screw machine cannot reach.
03
Rapid Prototyping
Turned and milled prototypes so the design is proven before the screw machine tooling is cut.
04
Part Surface Finishing
Anodizing, plating, bead blasting and laser marking, matched to the alloy and the mating surface.
05
Metal Die Casting
For housings and brackets that should not start life as bar stock at all.
06
Sheet Metal Fabrication
Enclosures, brackets and panels that pair with turned fittings in the same assembly.
Scope
Screw machine and turning scope at a glance
| Item | Range | Notes |
|---|---|---|
| Bar diameter | Ø4–32 mm | Larger work moves to CNC turning |
| Tolerance | ±0.005 mm | ±0.0002 in |
| As-turned finish | Ra 1.6–3.2 μm | Standard cut |
| Fine finish | Ra 0.8–1.6 μm | When geometry allows |
| Order quantity | No minimum order quantity | One prototype to 10,000+ pieces |
| Quote turnaround | Within 12 hours | Includes free DFM analysis |
| Production start | Within 24 hours | After drawing and material release |
| Shipping | Parts ship in 3–5 days | Standard production lots |
Why GreatLight
Numbers behind the shop
Screw machine work is only useful if the shop around it can keep the schedule and the tolerances.
15Y
Machining since 2011
Fifteen years of turned part production, with screw machine and CNC turning cells under one roof.
127
CNC machines in three plants
16 simultaneous 5-axis centers, 16 mill-turn centers and a Ø400 mm rotary table for secondary work.
±0.005
Millimetre tolerance
Held on turned diameters across a full lot, with first-article and in-process checks to confirm it.
99.99%
Qualification rate
Every lot is inspected before shipment. Material certs and inspection reports on request.
12 h
Quote and DFM
Drawings reviewed and quoted within 12 hours, with manufacturability notes attached.
0
Minimum order quantity
From one prototype to 10,000+ piece runs, with NDA available on request.
7,600 m²Manufacturing space
150Technicians on staff
3Wholly-owned plants
< 2%Historical late-delivery probability
Where it gets used
Turned part families we run in volume
Automotive & EV
Fittings and spacers that must hit the same diameter on every piece of a 20,000-piece lot.
- ±0.005 mm
- IATF 16949:2016
- 100% inspection
Medical Devices
Small stainless and titanium components where the surface finish is called out, not assumed.
- Ra 0.8–1.6 μm
- ISO 13485:2016
- Material cert
Electronics
Pins, standoffs and contacts turned in brass or copper, often with plating as the last step.
- Ø4–32 mm bar
- Plating available
- Laser marking
Industrial Machinery
Valve bodies, bushings and shaft collars that mix screw machine work with milled second operations.
- 127 CNC machines
- 3–5 day shipping
- No minimum order quantity
FAQs
Questions engineers ask before switching process
At what quantity does multi spindle screw machining beat CNC turning?
It depends on how many features the part has. A simple one-diameter part needs volume before setup pays back, usually several thousand pieces.
A part with four or five turned features crosses over sooner, because the cycle time difference is larger. Send the drawing and the annual quantity and we will say which route is cheaper.
What part size suits a screw machine?
Bar stock from Ø4 mm to Ø32 mm, with a length-to-diameter ratio that stays stable in the collet.
Long slender parts and anything above Ø32 mm move to our CNC turning cells, where the bar feeder and steady rest handle the overhang.
Can a screw machine cut threads and grooves in the same cycle?
Yes. Threading, grooving and facing are separate stations, so they run while the part is still in the collet.
That is where the time savings come from. The part does not leave the machine between operations, so there is no re-chucking error.
What about a flat or a cross-hole?
Those are secondary operations. We mill them on a mill-turn center or a 4-axis mill after turning, with the same datum carried through.
If the feature count is high, it may be cheaper to run the whole part on a mill-turn center instead. We will tell you that at the DFM stage.
Which materials run well on a screw machine?
Free-machining grades are easiest: 12L14 and 1215 steel, 303 stainless, C36000 brass, and 6061 aluminium.
304 and 316 stainless, 17-4PH, and titanium TA2 cut fine with adjusted speeds and tool grades. We will flag anything that needs a different approach before quoting.
How do you hold ±0.005 mm across a long run?
Cam motion repeats the same path every index, so the machine does not drift the way a servo loop can. Tool offsets are set on the first article and checked at intervals.
A CMM verifies the first article. In-process checks run through the lot, and every part is inspected before shipment.
What do you need to quote a screw machine part?
A 2D drawing with tolerances and a STEP file, plus the annual quantity and any finish callout.
Quotation and free DFM analysis come back within 12 hours. Uploads are confidential and an NDA is available on request.
Can you handle finishing and assembly as well?
Yes. Anodizing, electroless nickel, zinc and silver plating, bead blasting, tumbling and laser marking all run in-house or with qualified partners.
Laser marking needs a minimum character height of 1.5 mm. Tell us the mark location on the drawing so it lands on a machined surface.
Send the drawing, get the process recommendation
Upload your turned part with the annual quantity. We will quote it within 12 hours and tell you whether screw machine or CNC turning is the cheaper route.
12-hour quoteFree DFM analysis100% inspectionNo minimum order quantity
