Wexmar provides hard turning services for parts that must be finish machined after heat treatment. Using rigid CNC lathes and CBN or ceramic cutting tools, we turn hardened steel shafts, pins, bushings, bearing seats, and bores to final size without moving every part to a grinder. For engineers searching for hardened steel turning or a hard turning machine shop near me, Wexmar runs this work in Canastota, New York, near Syracuse, and ships nationwide.
What hard turning is
Hard turning is single-point turning of material that has already been through hardening. Instead of grinding every hardened diameter to size, a lathe with very stable setup and hard-cutting inserts removes the last few thousandths directly. Hard turning can produce shoulders, grooves, tapers, and contours in one setup that would need several grinding operations, and it handles interrupted surfaces and internal bores that are awkward to grind. Hard turning typically applies to material in a range of about 45 to 62 HRC; parts outside that range are reviewed individually.
When a buyer needs hard turning
- Shafts and pins that are through-hardened or case-hardened and then need final diameters
- Bearing seats, seal journals, and shoulders that must be concentric after heat treat
- Hardened bushings and sleeves with internal bores to finish
- Tooling components, punches, and wear parts that distort in heat treatment
- Parts where grinding would take several setups but turning can finish in one
Machines and process at Wexmar
Hard turning runs on our CNC lathes: Mazak Nexus QT200, Nexus 250, Nexus 100-II, 200 MS, Multiplex 6300Y, and Nexus 450-II, along with Doosan Lynx 2100A lathes and the Boss 552. We choose the machine by part size and required rigidity, and we keep hard-turning setups short and stiff with minimal tool overhang. The typical routing is rough turning in the soft condition with finish stock left on critical features, heat treatment through a qualified outside processor managed by Wexmar, and then finish hard turning. See our outside processing management page for how heat treat is handled.
Hard turning versus grinding
Grinding still produces the finest finishes and the tightest size bands, and we run a centerless grinder and a surface grinder on the same floor for that reason. Hard turning is often faster when a part has several diameters, shoulders, or grooves, because a single lathe program replaces multiple grinding setups. Many jobs combine the two: hard turn the profile, then centerless grind one critical diameter.
Typical tolerances and finishes
| Feature | Typical hard turning | Typical with follow-on grinding |
|---|---|---|
| Hardness range | about 45 to 62 HRC | about 45 to 62 HRC |
| Outside diameter | ±0.0005 in | ±0.0002 in |
| Bore diameter | ±0.0005 in | by review |
| Roundness | 0.0002 to 0.0003 in | 0.0001 in |
| Surface finish | 16 to 32 Ra | 8 to 16 Ra |
Values are typical. Actual results depend on hardness, part length, wall thickness, and heat-treat distortion, which is why we ask for the hardness spec and heat-treat method when quoting.
Materials suited to hard turning
Common hard-turned materials include through-hardening alloy steels such as 4140, 4340, and 52100, carburized grades such as 8620 after case hardening, 400-series and 17-4 PH stainless in hardened conditions, and tool steels. Soft materials and most non-ferrous alloys do not need hard turning and are machined conventionally.
Planning for heat-treat distortion
Heat treatment moves parts. Long shafts can bow, thin rings can go oval, and bores can shrink or grow. When we plan a hardened steel turning job, we leave finish stock on the features that matter, choose datums that survive heat treat, and check parts on return from the outside processor before finish machining begins. Parts that come back outside a workable straightness are flagged before any finish time is spent on them.
Quantity fit
Hard turning suits prototypes, repair and replacement parts, and production runs. For small lots it avoids the setup time of multiple grinding operations. For production it keeps the full profile on one machine and one program. Lot sizes from a few pieces into the thousands are typical.
Inspection deliverables
Hard-turned parts are measured with calibrated micrometers and bore gages and verified on Brown & Sharpe CMMs when the print calls for roundness, runout, or datum-referenced features. We provide CMM reports, AS9102-format first articles, material certifications, heat-treat certifications from the outside processor, and heat-lot traceability under an ISO 9001:2015-aligned quality system.
Getting a quote
Include the hardness specification, heat-treat method, and finish callouts with your drawing. You can upload a drawing for an instant estimate, and a human estimator confirms every quote before release. Call (315) 400-2654 or email ron@backwell.com, Monday through Friday, 7 a.m. to 4 p.m. Eastern.