01
Tolerance called tighter than the function needs
A ±0.005 mm callout on a bore that locates nothing forces small stepovers, extra tool changes and slower feeds. The part passes inspection and costs three times what it should have.
Reference Library
Machinist Resources for Real Shop Decisions
Written for engineers who have to pick a grade, a tolerance and a thread callout before the drawing is released. Use it to check whether a part belongs on a mill, a lathe, or neither.
±0.005 mm toleranceRa 0.2–0.8 μm finishNo MOQ12-hour quote
127High-precision CNC machines
16Simultaneous 5-axis centers
4,000 mmMaximum processing size
99.99%Qualification rate
Where drawings go wrong
Four Problems That Show Up After the Quote
Most of these are decided before the first chip is cut.
02
Wall thickness that moves under clamping
Thin ribs and 0.8 mm walls deflect when the vise closes. The first article measures fine, then the second op releases the stress and the flatness drifts out.
03
Thread callouts with no depth or class
A tapped hole written as M6 with no depth, no thread class and no note on whether it is cut or formed leaves the shop guessing. Guessing produces a hole that a screw either bottoms out in or strips.
04
Material chosen by habit, not by load
316 stainless gets specced because it worked on the last job. It machines slower than 303, work-hardens at the surface and adds cost that the part's load case never asked for.
How we work
Turning a Drawing Into a Process Plan
The process plan is where cost is won or lost.
Operation planning
Milling, Turning or Both
Prismatic parts with pockets, faces and drilled patterns go on a mill. Round parts with a single axis of symmetry go on a lathe. Parts that are both, like a shaft with a cross-drilled flange, are cheaper on a mill-turn center because the part never gets re-fixtured.
We run 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers, so the routing is chosen by geometry rather than by whichever machine is free. That choice sets the datum scheme, the number of setups and the true position stack-up before any tooling is ordered.
- 1One setup where possibleFewer datums means fewer stack-up errors.
- 2Fixture before feedsClamping decides whether a thin wall holds tolerance.
- 3In-process checksWe measure between ops, not only at the end.
Material behavior
Reading the Grade Before the First Cut
Stainless grades do not machine alike. 303 is free-cutting because of its sulfur content and holds a good finish at higher feed. 304 work-hardens fast, so a tool that rubs instead of cuts will burnish the surface and then break. 316 and 316L machine slower still but resist chlorides, which is why they show up in marine and medical parts.
For alloy steel, 1018 machines cleanly and welds well but has limited through-hardening depth. 4140 carries more strength and responds to heat treatment, at the cost of lower surface speed and more attention to chip evacuation. We stock 1018, 1045, 4130, 4140, 4340 and A36 in the steel group.
- 1Chip color tells the storySilver chips mean the speed is right; blue means it is not.
- 2Heat treatment before finishingHardened stock moves after machining.
- 3Free-cutting grades for volume303 and 12L14 cut cycle time on unloaded features.
Selection
Matching the Operation to the Part
Use this to sanity-check a routing before you release the drawing.
| Part geometry | Best operation | Why |
|---|---|---|
| Pockets, faces, hole patterns | 3-axis mill | Simple datums, low setup count |
| Round features on one axis | CNC lathe or mill-turn | Turning beats milling on diameter |
| Shaft with cross-drilled flange | Mill-turn center | No re-fixturing, position holds |
| Contoured organic surface | Simultaneous 5-axis | Tool reaches without re-clamping |
| Thin plate, high flatness | Mill with vacuum or soft jaws | Clamping pressure stays even |
| Long extrusion, 4,000 mm | Large-travel 3-axis | Travel fits in one pass |
What we run
Machining Services Behind the Reference Data
One shop for the whole part route.
01
5 Axis CNC Machining
16 simultaneous 5-axis centers for contoured surfaces, undercuts and parts that would need four setups on a 3-axis machine.
02
4 Axis CNC Machining
12 four-axis mills for cylindrical work with cross features, indexed in one setup.
03
3 Axis CNC Machining
27 machines covering travel envelopes up to 4,000 × 400 × 150 mm for large plate and extrusion work.
04
CNC Milling & Turning
Mill-turn centers and lathes handle Ø400 mm rotary work and turned parts from one-off to 10,000+ runs.
05
Rapid Prototyping
Machined and printed prototypes for fit checks before the production tool is committed.
06
Part Surface Finishing
Anodizing, plating, powder coating, bead blasting and laser marking to the drawing's finish callout.
Capability
Machine and Finish Ranges
Numbers you can design against.
| Item | Range | Note |
|---|---|---|
| Tolerance | ±0.005 mm (±0.0002 in) | On controlled features |
| Fine finish | Ra 0.2–0.8 μm | Achievable on turned surfaces |
| High finish | Ra 0.8–1.6 μm | Common milled spec |
| As-machined | Ra 1.6–3.2 μm | Standard milled finish |
| Largest travel | 4,000 × 400 × 150 mm | Single setup |
| Rotary table | Ø400 mm | 4th axis indexing |
| Run size | 1 to 10,000+ parts | No minimum order quantity |
| Quote turnaround | 12 hours | Includes DFM notes |
Why this shop
What the Numbers Actually Mean
Six figures that decide whether your part ships on spec.
15Y
Machining since 2011
Fifteen years of process data on stainless, alloy steel, titanium and aluminium families.
127
CNC machines on the floor
Capacity spread across three wholly-owned plants covering 7,600 m².
±0.005
Millimetre tolerance
Equivalent to ±0.0002 in on controlled features.
150
Technicians
Process engineers and machinists who read the drawing before quoting it.
99.99%
Qualification rate
Backed by raw material checks, in-process monitoring and final inspection.
12H
Quote and DFM
Quotation with free DFM analysis inside 12 hours.
Industry fit
What Each Sector Demands, and What We Hold
Aerospace
Thin-wall brackets and housings where flatness and hole position decide assembly.
- ±0.005 mm
- 5-axis
- Ra 0.8 μm
Automotive & EV
Housings, manifolds and drive components that must repeat across a production run.
- IATF 16949
- 10,000+ parts
- 100% inspection
Medical Devices
316L and titanium instrument parts with deburred edges and clean surface finish.
- ISO 13485
- 316L
- Ra 0.2–0.8 μm
Robotics & Automation
End-effector plates and joint housings where mass and stiffness both matter.
- 7075-T6
- ±0.005 mm
- 1 to 10,000
FAQs
Questions Engineers Ask Before Releasing a Drawing
When should a part go on a mill-turn center instead of a mill?
When the part has a turned axis plus features that sit off that axis: cross holes, flats, slots on a flange. A mill-turn center indexes the part without releasing it, so the relationship between the bore and the cross feature stays inside one setup tolerance.
If the part is purely prismatic, a 3-axis mill is faster and cheaper. Mill-turn adds value only when re-fixturing would cost you position tolerance.
Why does 304 stainless sometimes come back with a poor surface finish?
304 work-hardens at the cut. If the insert rubs instead of shearing, the surface hardens, the next pass cuts through that hardened layer, and the finish degrades with each step.
The fix is feed and depth of cut, not a different insert grade. Take a heavier chip and keep the tool moving. A light finishing pass over work-hardened 304 makes it worse.
Do tapped holes and threaded holes mean the same thing on a drawing?
No. A tapped hole is made by cutting or forming threads into a drilled hole with a tap. A threaded hole is the broader term covering any internal thread, including threads produced by single-point boring on a lathe or by thread milling.
In practice the difference shows up in callouts. Specify the thread class, the depth and whether the thread is cut or formed, because formed threads need a different pilot diameter.
What is the difference between 1018 and 4140 for a machined part?
1018 is low-carbon, machines easily and welds well, but it cannot be through-hardened to high strength. It suits brackets, shafts and plates that see moderate load.
4140 is a chromium-molybdenum alloy steel that responds to quench and temper, reaching much higher strength. It machines at lower surface speed and needs consistent chip evacuation. Choose it when the part is loaded, not when it is merely structural.
How tight a tolerance should I actually call out?
Call out only what the function needs. A locating bore that sets a gear mesh needs a tight tolerance. A clearance hole for an M6 screw does not.
Every extra tight callout adds inspection time, slower feeds and more scrap risk. We hold ±0.005 mm where it matters and tell you in the DFM notes where a looser callout would save money without affecting fit.
Is a chamfer or a fillet the right call at a part corner?
A fillet reduces stress concentration, so it belongs where the part sees fatigue loading. A chamfer is cheaper to produce, deburrs easily and protects the edge during handling.
On a sharp internal corner in a hardened part, a fillet also removes a stress riser that can start a crack. On an outside edge that only needs protection, a chamfer is enough.
What do I need to send for a quote with DFM feedback?
A 3D model in STEP or IGES plus a 2D drawing for tolerances, thread classes and finish callouts. If the drawing is missing, note the critical dimensions in the email.
We return the quotation and a free DFM analysis within 12 hours, listing any feature that will drive cost or risk. Uploads stay confidential and an NDA is available on request.
Can you machine a single prototype and then ramp to production?
Yes. There is no minimum order quantity, so the same shop runs the first article and the 10,000-part order. Tooling, fixtures and inspection plans carry over.
Parts ship in 3–5 days on standard work, and production can start within 24 hours of a released order.
Send the Drawing, Get a Process Plan Back
Upload a STEP file and a 2D drawing. You get a quotation and free DFM analysis within 12 hours.
12-hour quote100% inspectionNo minimum order quantityNDA on request
