Precision Grinding
Surface, cylindrical and centreless grinding to sub-micron flatness and finish
When a milled or turned surface is not flat enough, round enough or smooth enough, grinding takes over. We hold flatness within 0.003 mm and finishes to Ra 0.1 µm on hardened and soft materials alike.
Flatness under load
Post-heat-treat correction
Finish that controls wear
Why it works
Flatness under load
Sealing faces ground flat to 0.003 mm stay sealed when the bolts are torqued — a milled face at 0.05 mm simply will not.
Post-heat-treat correction
Hardening moves steel. Grinding after heat treatment restores the geometry the drawing asks for instead of hoping the distortion falls inside tolerance.
Finish that controls wear
Ra, Rz and cross-hatch angle are measured and reported, because on a running surface texture determines oil film, friction and service life.
Process specification
| Surface grinding capacity | 600 × 300 × 300 mm |
|---|---|
| Cylindrical capacity | Ø 250 × 800 mm |
| Flatness | 0.003 mm / 300 mm |
| Diameter tolerance | ±0.002 mm |
| Roundness | 0.001 mm |
| Surface finish | Ra 0.1 µm (0.025 µm lapped) |
Tighter tolerances than those listed are achievable on review — please mark critical dimensions on your drawing.
Typical applications
- Bearing seats & journals
- Sealing & mating faces
- Die plates & tooling bases
- Hydraulic spools & sleeves
- Dowel pins & rollers
- Gauges & inspection standards
Compatible materials
Surface grinding
Reciprocating-table surface grinders produce flatness within 0.003 mm over 300 mm and parallelism within 0.005 mm. This is the process that makes gauge blocks, die plates, fixture bases and sealing faces do their job.
Magnetic and vacuum chucking is selected by material: ferrous parts on magnetic chucks with the demagnetising cycle documented, non-ferrous on vacuum or mechanical fixtures.
Cylindrical and centreless grinding
Cylindrical grinding holds diameters to ±0.002 mm with roundness within 0.001 mm — the tolerance band required by precision bearing seats, hydraulic spools and spindle journals.
Centreless grinding takes over for volume: pins, dowels, shafts and rollers run through at rates milling cannot approach, with consistent diameter along the full length and no centre-hole witness marks.
Finishing operations
Where the drawing demands better than ground finish, we add lapping and polishing. Lapped flatness reaches 0.001 mm and optical polishing achieves Ra 0.025 µm on hardened steel and carbide.
Superfinishing and honing are available for bores where surface texture controls oil retention and wear — cross-hatch angle and Rz are specified and verified rather than left to chance.
What grinding fixes
Distortion after heat treatment, sealing faces that must be flat under bolt load, bearing seats where 0.01 mm of roundness error becomes vibration at 10,000 rpm, and any surface where the customer's drawing states a finish a cutting tool cannot reliably reach.
Frequently asked
How quickly will I receive a quotation?
Most quotations are returned within 24 working hours. Simple turned or milled parts are often priced the same day; assemblies, multi-process jobs and requests requiring a material enquiry may take up to two working days. If a quotation will take longer, we tell you when to expect it rather than leaving you waiting.
What files do you need to quote?
A 3D model in STEP, Parasolid (X_T) or IGES is enough to start. Where the part carries tolerances tighter than ISO 2768-m, GD&T, surface finish callouts or thread specifications, please add a dimensioned 2D drawing as PDF or DWG. Telling us the quantity, material and required finish avoids a round of questions and usually gets the price back the same day.
Is there a minimum order quantity?
No. We machine single prototypes as readily as 20,000-piece releases. There is a minimum order value on very small jobs to cover setup and programming, which we state clearly in the quotation — there are no charges that appear later.
What actually drives the price of a machined part?
Four things, roughly in order: the number of setups, cycle time, material cost and the tightest tolerance on the drawing. A tolerance of ±0.01 mm where ±0.1 mm would function can add 30 % to the price, and a feature that forces a fourth setup can add more. Our quotations flag these drivers so you can decide whether the requirement is worth the cost.
Need this process for your part?
Send your drawing and we will confirm feasibility, cost and lead time.
- Reviewed by a manufacturing engineer
- NDA available before file exchange