Precision Grinding Services

The last micron is the expensive one. It is also the one we are set up for.

ID/OD grinding and surface grinding — tolerances to 0.005 mm, finishes to Ra 0.1 μm. Plunger-barrel pairs that hold back 1,050 bar, seal faces, bearing seats, spool-and-sleeve fits. All in-house, all verified by our own metrology. Eleven grinding machines — cylindrical, internal, surface, centerless, jig, and center-hole — none older than the process requires. Deep-hole honing now lives on our Deep Hole Drilling page →

Send the drawing — the last micron is the one we are set up for. NDA welcome.

Why the Final Cuts Are the Hardest

Roughing removes metal. Finishing removes excuses:

Heat is the enemy now

A grinding burn is invisible to the eye and fatal to fatigue life. Wheel selection, dressing intervals, and coolant delivery decide whether the surface is precision or just shiny

Size drifts across a batch

Part #1 and part #500 must be identical to microns while wheels wear and temperatures shift. Batch consistency is a process discipline, not a machine specification

Roundness is its own dimension

A bore can be in tolerance at every measured point and still be out of round. Cylindricity, roundness, and straightness need their own measurement strategy

Matched fits multiply everything

A spool and sleeve working together need clearance measured in single microns, matched as a pair. Grinding each to print is not enough; they must be ground to each other

Honing note

Deep-hole and precision-bore honing (the controlled crosshatch texture that holds oil, guides the plunger, and seats the seal) now lives on our Deep Hole Drilling page →

Grinding a hardened shaft — the finish is a measurement, not a shine

Capability

Process	Capability
Cylindrical grinding (OD)	Shafts, sleeves, bearing seats, plungers — up to Ø315 × 1,500 mm; roundness to 0.0005 mm, finish to Ra 0.1 μm
Internal grinding (ID)	Bores up to Ø200 × 1,000 mm; roundness to 0.0005 mm, concentricity to 0.002 mm
Surface grinding	Flatness-critical faces: seal surfaces, valve plates, precision bases — strokes up to 2,000 × 600 × 600 mm; flatness to 0.005 mm
Centerless grinding	Small-diameter shafts and pins, Ø40 × 120 mm (plunge) / 140 mm (through-feed); roundness to 0.002 mm
Double-side lapping	Parallel faces to flatness 0.0005 mm / Ra 0.1 μm
Jig grinding	Precision hole location — hole spacing to 0.005 mm, roundness to 0.002 mm
Center-hole grinding	Center holes up to Ø300 / workpieces to Ø180 × 1,000 mm; runout to 0.001 mm
Minimum part size	Down to ≈ Ø1 mm — plunger-type small parts
Hardened steels	45–65 HRC, ground as routine
Honing	→ moved to Deep Hole Drilling page
Shop envelope	Difficult alloys (Inconel, titanium, hardened steels) routine
Verification	In-house metrology: CMM, roundness tester, roughness testers, full gauge suite — report with every order

STUDER cylindrical grinding machine with handwheels and digital readout

Cylindrical grinder — one of eleven on the floor

Where Precision Finishing Proved Itself

The plunger-barrel pair — grinding and honing’s hardest exam.

At the heart of every common-rail fuel unit runs a plunger in its barrel: a matched pair holding back 1,050 bar of fuel pressure, cycle after cycle, for the life of an engine. The fit clearance lives in single microns — held in the 1.2–1.8 μm band, roundness within 3 μm; the bore texture controls fuel film and wear. This is the component class where grinding and honing either work — or the engine does not.

Parts down to Ø1 mm are ground here. Hardened steels up to 65 HRC are routine here.

We make these pairs. They sit inside the common-rail units built when the technology and the equipment could not be bought — certified by seven classification societies, and serving aboard China’s polar research vessel.

Beyond fuel systems, the same disciplines finish bearing seats and air seals for civil aerospace programs, spool-and-sleeve fits for control valves, and the sealing surfaces of deep-sea manipulator components — wherever the last micron decides whether the part works.

FAQ

Q: What surface finish can you hold?

To Ra 0.1 μm on our precision grinding machines, where the part geometry and material allow. Finish is a system output — wheel, coolant, machine condition, and material all contribute; send the drawing and we will commit to a number per surface.

Q: Can you grind hardened steels and superalloys?

Yes — hardened steels from 45 to 65 HRC, Inconel, and titanium are routine here. We do not grind carbide or ceramics — for those we will tell you straight, and route you elsewhere if we can help.

Q: Do you handle matched-pair grinding (spool/sleeve, plunger/barrel)?

Yes — matched sets are our fuel-system heritage. Pairs are ground and honed to each other and shipped as matched assemblies. Fit clearances in the 1.2–1.8 μm band, roundness within 3 μm.

Q: What is your honing capability?

Honing has moved to our Deep Hole Drilling page — bores Ø20–200 mm, up to 4,000 mm long, same group, same in-house metrology →

Q: Can you grind large parts?

Our shop envelope reaches Ø1,000 × 10,000 mm; our largest grinding envelope is Ø315 × 1,500 mm (cylindrical) and 2,000 × 600 × 600 mm (surface). Large-part grinding depends on geometry — send the drawing for an honest answer.

Q: What is the smallest part you can grind?

Down to about Ø1 mm — plunger-type small parts are routine.

Q: Can you grind spherical or R-contour surfaces?

When a contour needs the final tolerance, we route it to the process that holds it — CNC turning or milling with interpolated tool paths, or a formed wheel where the geometry suits. Grinding is for what grinding does best: cylindrical, internal, flat, and matched surfaces. We tell you which process your feature needs before you order.

Why the Final Cuts Are the Hardest

Capability

Where Precision Finishing Proved Itself

FAQ

Send the Part Where the Last Micron Decides