Spindle housings
Bearing bores ground in line, flange faces square to the bore, mounting holes position-checked after hardening.
MACHINE TOOL · HARDENED · GROUND
Machine tool components that hold their geometry.
Spindle housings, chuck bodies, guide-rail bases and bearing seats — turned, milled, hardened and ground, with runout measured and reported at 0.002 mm on ground features.
WHAT WE SOURCE
The parts that decide whether the machine repeats.
These are rarely the biggest parts on the machine and almost always the ones that get replaced first. Geometry, hardness and surface finish have to survive heat treatment and grinding.
Chuck bodies
Front and rear bodies in 45 steel, jaw slots milled and ground, runout checked on the mounting register.
Guide-rail & linear bases
Hardened SKD11 or 42CrMo rail bases with ground mounting faces and parallelism held along the full length.
Bearing housings & seats
SUJ2 and 42CrMo seats, ground for fit and roundness, with bore-to-face squareness reported.
Dresser spindles & arbors
Thin, long parts where runout and taper are the whole specification — ground between centres.
Tailstock & quill parts
Quills, sleeves and locking components, often one-off replacements for older machines.
TOLERANCES & PROCESS
Rough, harden, then grind.
Never the other way round.
Distortion is decided before the first cut. We rough machine, release stress, heat treat, then finish grind — and measure after grinding, not before.
- 01
Turn-mill composite
Coaxial features and cross holes in one setup, so runout stays tied to one datum.
- 02
Hardening to HRC 58–60
Vacuum or salt-bath hardening with stress relief before finishing.
- 03
Finish grinding
Cylindrical and surface grinding for bore fit, roundness and runout.
| Materials | 34CrAlNi7, 42CrMo, SUJ2, SNCM439, SKD11, 45 steel, FC250 |
|---|---|
| Hardness | HRC 58–60 on tool steel parts |
| Runout | 0.002 mm on ground features |
| Roundness | 0.003 mm |
| Surface finish | Ra 0.4 µm ground |
| Turning capacity | Ø2 – Ø320 mm |
| Inspection | CMM, runout fixture, hardness check |
| Documentation | Dimensional report, material cert, hardness record |
| Typical lead time | 10–15 working days with heat treatment |
WORK
Representative parts.
Rail base · SKD11
Linear rail base
Shafts & seats
FAQ
What engineers ask first.
How do you actually hold 0.002 mm runout?
By grinding after hardening, between centres or in the same fixture that machined the datum, then measuring on a runout fixture — not by trusting a CMM reading on a part that moved during heat treatment.
Can you match a spare part for an older machine?
Yes, if you can send a sample or a dimensioned sketch. We measure, model, and quote — including the heat treatment and grinding route the original likely used.
What about distortion after hardening?
We leave grinding stock, stress-relieve before hardening and finish after. If a part is beyond recovery we scrap and remake it — we don't ship it straightened and hope.
Do you do single pieces?
Yes. Most of these parts start as one or two pieces for a repair or a prototype, then move to small batches of 20–200.
Send a drawing. Get a process route and a price.
We'll tell you whether the tolerance needs grinding, and what the heat treatment will do to your budget.