Article · Micro-Machining · Medical · Electronics
Big Difference in Micro-Machining: SS & SR Miniature End Mills
Edge geometries you can't see with the naked eye decide whether a 0.005" cutter holds size. RobbJack's SS and SR Series miniatures cut to micron tolerances — when nothing less will do.
0.005"
smallest cutting diameter
0.000039"
tolerances in microns — finer than a human hair
0.0002"
hand-selected diameter increments
At miniature scale the rules change. The edge geometries that decide quality and consistency are too small to see with the naked eye, and the usual shop habits — calipers, micrometers, guessing a depth of cut — quietly wreck the tool and the part. RobbJack's SS and SR Series carbide miniatures are built for that world: the most accurate and long-lasting carbide miniatures on the planet, ground in every diameter increment of 0.001".
Micro, defined
Miniature tool edge geometries may not be visible to the naked eye, but they're what hold machining quality and consistency at this scale. RobbJack grinds them in every increment of 0.001" so you can match the tool to the feature instead of rounding to the nearest stock size.
- Cutting diameters starting at 0.005".
- Tolerances held in microns (0.000039") — smaller than a human hair.
- Diameters hand-selected to the nearest 0.0002".
- Primary relief angles ground to maximize machining performance.
- CVD diamond coating available for the most abrasive applications.
Where miniatures earn their keep
- Micro-electromechanical systems (MEMS) and nanotechnology.
- Dental and medical appliances.
- Die and mold detail work.
- Aerospace components.
- Electronics.
Running a miniature tool
At this scale, rigidity and runout are everything — a few tenths of deflection is the whole tolerance. Keep the cut light and the tool true:
- Take no more than 25% of the tool diameter as axial (Z) depth per pass.
- Use accurate, high-precision tool holders.
- Indicate the shank of the tool in to minimize runout before you cut.
Measuring without breaking the tool
You can destroy a micro end mill just measuring it. Skip contact gauging on the cutting edge entirely — don't put micrometers or calipers on the cutting diameter; use non-contact measurement instead, and use shim stock to set tool length.
Micro-machining is won on geometry you can't see and runout you can't feel — match the diameter to the feature, keep the cut to 25% of diameter, and never touch the edge with a caliper.
Tools in this story
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