Blanchard Grinding vs. Precision Grinding

Grinding is a common machining process used to create metal parts. The process uses abrasives to shape materials to specific dimensions and shapes, followed by applying a surface finish. Two types of grinding are Blanchard grinding and precision grinding. While Blanchard grinding is best for materials with wide surface areas, precision grinding forms parts with small surface areas.

We will explain other differences between these two methods, in addition to their respective benefits and drawbacks. Ultimately, the better choice will depend on the particular needs of your application.

What Is Blanchard Grinding?

The Blanchard Machine Company invented blanchard grinding in the early twentieth century. Also called rotary surface grinding, this method utilizes specially designed holders or magnets to keep the workpiece in place. Operators use a Blanchard grinding machine consisting of a vertical spindle and wheel to grind along a single side of the workpiece. Blanchard grinding can achieve tolerances down to +/- 0.001 inch and surface finishes of about 65 RMS.

The most popular application for Blanchard grinding is metalwork involving iron or other ferrous metals. However, other applications may use this process for certain plastics and non-ferrous metals, albeit at slower production rates and increased costs.


To summarize, Blanchard grinding offers these key benefits compared to other grinding processes:

  • Fast
  • Cost-effective
  • Effective for parts with large surfaces


Certain applications may not be well suited to Blanchard grinding due to these drawbacks:

  • Less precise than precision grinding
  • Leaves a grinding mark


What Is Precision Grinding?

Precision grinding involves cutting away materials from components that have small surface areas and need superior finish, parallelism, or flatness. The precision grinding process typically helps complete parts after they have undergone other machining processes.

Precision grinding consists of several subtypes that offer superior precision. For example, the horizontal spindle surface grinding process uses an abrasive wheel rotating at a high speed to grind away a workpiece’s surface. Another type of precision grinding is cylindrical grinding, which removes material from cylindrical parts.

Applications that use precision grinding processes include molds and dies, bushings, machine components, stampings, pistons, and shafts. The method can achieve surface finishes of around 10 RMS and tolerances as tight as +/- 0.0001 inch.


Precision grinding offers these main advantages:

  • Optimal precision
  • Versatility
  • Smooth finish


At the same time, precision grinding has the following drawbacks:

  • Lack of compatibility with larger workpieces
  • Slower than Blanchard grinding


Key Differences Between Blanchard and Precision Grinding

When selecting the right grinding process for your preferred materials, here are some key differences to keep in mind:

  • Surface area: For bigger workpieces with larger surface areas, Blanchard grinding is more ideal. Precision grinding works better for components with smaller surface areas.
  • Precision: Precision grinding can achieve a higher degree of precision than Blanchard grinding.
  • Smooth vs. rough finish: For parts requiring a very smooth finish, precision grinding works best. Blanchard grinding, on the other hand, produces moderately smooth finishes.
  • Speed: If an application requires maximum efficiency—particularly for large parts with greater surface areas—Blanchard grinding produces parts more quickly. 


Choose Nation Grinding for Grinding and Coating Services

Nation Grinding, Inc. offers custom Blanchard and precision grinding services, which include precision vertical grinding, thread and jig grinding, cylindrical grinding, and ID grinding. With our added coating services, we have provided ground and coated parts for use in a variety of sectors, including the military, aerospace, electronics, and medical industries.

To learn more about our capabilities or request a quote, contact us today.

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