Cylindrical grinding

Enlarging a uniform bore from 20.000 to 20.100 mm requires 0.100 mm diametral enlargement and 0.050 mm radial removal. Check incoming form, wheel access and datum relationships before assigning stock or treating a single-clamping route as feasible.

OD wheels reach external surfaces. ID wheels need bore access. Establish the drawing datum and whether centers, a chuck or a collet provide the required support. UNITED GRINDING, cylindrical-grinding overview, undated

Choose the motion and access

Norton distinguishes traverse and plunge ID grinding and identifies profiled internal features as a plunge application. It also explains that a long or insufficiently rigid ID quill can deflect, affecting geometry, finish and wheel wear. Bore reach is consequently more than a collision-clearance question. The work material, quill and wheel must be considered together; reducing the wheel diameter to enter a bore does not by itself qualify the operation. Norton, IDeal-Prime application discussion, 22 February 2022

Workholding, support and datum relationships

Select the locating surfaces before choosing the final grinding sequence. In the process handoff, identify which centers, bore, journal or face will locate the part, which surfaces will be ground in that setup, and which relationships will need verification after reclamping. These are planning questions: a process name alone cannot establish the drawing's datum system or the resulting coaxial relationship.

Long, thin workpieces can deflect under grinding forces even when held between centers. STUDER describes two-jaw steady rests as a means of support and distinguishes spring-loaded stabilization from fixed, preloaded support. Its guidance also discusses pre-grinding and the influence of steady preload on subsequent diameters. Treat these as setup dependencies requiring a qualified sequence, rather than importing a generic length-to-diameter threshold or spindle-speed rule into every job. Document where the steady contacts, whether that support surface is pre-ground, and how the part is inspected after release. STUDER, two-jaw steady-rest guidance, undated page

Wheel condition is part of the process

Truing and dressing serve different purposes. Norton describes truing as restoring wheel geometry and its relationship to the rotation axis, and dressing as conditioning the grinding face to expose cutting grains or establish the desired cutting condition. They may occur together, but a wheel with the intended profile is not necessarily cutting effectively. Record the wheel specification, dressing method and interval in a production trial. A dimensional correction is not evidence that the abrasive face has been restored. Norton, 26 June 2025

Finish depends on interacting choices: operating parameters, dressing, grit, coolant delivery and machine condition. Norton's guidance includes OD/ID examples and notes the tradeoff between finish improvements and cycle time. Select the abrasive and bond for the actual material, hardness, contact and machine, and respect the wheel's marked operating-speed limit. Compare samples across the intended dress interval, not only immediately after dressing. The resulting surface-texture requirement should name the parameter and evaluation conditions; “ground finish” is not a numerical acceptance criterion. Norton, 20 August 2021

Thermal integrity and cooling

UNITED GRINDING explains that grinding heat can change near-surface microstructure and residual stress and can produce cracks. Its burn guidance treats wheel cutting condition, process parameters and delivery of coolant to the contact as interacting influences. A pump indication does not establish that the jet reaches the grinding gap effectively. Specify any required burn, crack or other surface-integrity examination separately from size and texture acceptance; do not use an attractive surface as proof of an undamaged subsurface. No coolant flow, concentration or in-feed recipe is universal across these applications. UNITED GRINDING, 10 August 2020

Bounded producer example

The STUDER S33 brochure, V1, February 2023, describes a universal wheelhead configuration with up to two external grinding spindles and one internal spindle. It also describes internal, external and face grinding within a single clamping. This illustrates a route for reducing reclamping, not a claim that every S33 has that wheelhead or that all surfaces of any part are reachable. Confirm the installed workhead, wheelhead, internal spindle, fixtures and clearances for the proposed component. Catalog axis resolution and workhead accuracy should not be relabeled as guaranteed finished-part tolerances. STUDER S33 brochure, printed revision on back page

Original stock-removal example

Use the ideal uniform bore above and a 30.0 mm length. Ignore chamfers, length change and incoming form error:

• Diametral enlargement = 0.100 mm.
• Radial stock removed = 0.100 / 2 = 0.050 mm.
• Removed volume = π/4 × (20.100² − 20.000²) × 30.0 = 94.48 mm³.

The radial allowance is half the diameter change. This calculation is a geometric quantity for comparing trials, not a one-pass recommendation or a prediction of heat, cycle time or power. A real cleanup allowance must also accommodate the incoming feature's location and form; the simplified model makes no allowance for those errors.

Define acceptance before proving capability

Measure size, form and datum-related behavior as separate requirements. A diameter reading cannot describe the entire surface. Mitutoyo distinguishes roundness, cylindricity and runout and explains how measurement centering, leveling and filtering affect the result. Roundness at one section does not establish cylindricity over the full length; a datum-related runout check addresses a different relationship. Record measured sections, axial coverage, association method and filtering as applicable to the specified evaluation. Mitutoyo, geometric verification guidance, undated

For the supplier handoff, provide the material and heat-treatment condition, incoming allowance envelope, locating features, drawing requirements, required surface-integrity examinations and quantity. Request results from the actual workholding and grinding sequence, including the planned dress interval. This is a proposed qualification structure; the drawing, contract and agreed inspection procedure set the acceptance limits.