Working in the machining and grinding world means grinding tools to around five microns’ tolerance for most high-end cutting tools. But just how tight is this tolerance?

A micron (μm) is a unit of length equaling one millionth of a meter or 1/26,000 of an inch. For perspective, a single human hair is 80μm in diameter, and a bacterium is around 3μm across.

Microns could be described as “impossibly small,” but machinists regularly do the impossible and produce tools and parts to within one- or two-microns’ tolerance.

Supplying Tight-tolerance Industries

Tolerance represents the amount of allowed variance in the dimensional accuracy of a part – and industries like aerospace and government/military require consistently uniform parts with consistently super-tight tolerances.

When parts have to perform in extraordinary conditions – like flying hundreds of miles an hour or enduring 3000°F temperatures when reentering Earth’s atmosphere – they must fit perfectly with the parts around them. A wiggling part might be inconvenient on a bicycle but would be catastrophic on a spacecraft. Aerospace, military, and other industries have to consider life safety and equipment integrity/longevity costs and can therefore accept parts nothing short of perfection.

For manufacturers supplying these industries, reliable production of super-tight tolerances is also an economic concern. No shop wants to waste material or scrap parts. But when the difference between a part roving around Mars and getting thrown into the bin is a matter of one or two microns, precision grinding is worth the tools and effort.

Machinists and grinding specialists need the right tools and skills to supply these industries. In the grinding of cutting tools, minimizing runout, or how much one given reference feature or features vary with respect to another datum when the part is rotated 360° around the datum axis – is essential. In lay terms, good run-out (in this case, “runout” is synonymous with concentricity) means the workpiece will have miniscule or no ‘wobble’ when spun around a single point.

Improperly set up and maintained work-holding is one of the leading causes behind bad run-out, the production of bad tools, increased scrap rates, unhappy customers, and lost money for your business. High-precision chucks hold tools very straight and give excellent run-out, usually within a couple of microns.

Every Micron Matters

The difference between accepted and scrapped parts for aerospace and other exacting industries comes down to sometimes a single micron.

Quality precision grinding machines can achieve microscopic tolerances over and over, helping shops meet customer needs even in the most precise and demanding industries.

As the maker of MÄGERLE, BLOHM, JUNG, STUDER, SCHAUDT, MIKROSA, WALTER, and EWAG machines, UNITED GRINDING machines help you transform your business down to the micron. See how J&E Precision Tool Inc. uses their STUDER S33 to excel in the aerospace industry.