| Cutting Diameter (Fractional) |
Shank Diameter (Metric Focus) |
Flute Length |
Overall Length |
| Φ 1/8" |
3.17mm (0.12") |
19mm (0.76") |
61mm (2.40") |
| Φ 3/16" |
5.0mm (0.20") |
24mm (0.94") |
83mm (3.27") |
| Φ 1/4" |
6.0mm (0.24") |
26mm (1.02") |
96mm (3.80") |
| Φ 5/16" |
8.0mm (0.31") |
32mm (1.26") |
112mm (4.41") |
5. Professional Industry Applications
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Cross-Platform CNC Machining: The mandatory set for metric-based machine shops manufacturing export components for US aerospace, automotive, and defense contractors requiring fractional hardware.
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Custom Tool & Die: Precision finishing of alignment holes for standard imperial dowel pins in injection molds and stamping dies.
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3D Printing & Prototyping: Cleaning out and trueing holes in rapidly prototyped parts to accept standard 1/4" and 5/16" linear motion rods or brass bushings.
6. Operation and Safety Guidelines
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Machine-Use Optimization: These are cylindrical-shank chucking reamers designed for machine use (Lathe, CNC Mill, or Drill Press). Ensure your collet or chuck is free of debris before inserting the metric shank to guarantee absolute concentricity.
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Pre-Drill Tolerances: Chucking reamers are finishing tools, not drill bits. You must pre-drill the hole approximately 1/64" (0.4mm) undersized before feeding the reamer into the workpiece.
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Coolant Application: When reaming metals, always flood the cutting zone with high-quality machining coolant or cutting oil. Straight flutes do not actively eject chips upward like spiral flutes, so heavy fluid application is required to flush the hole and prevent galling.
7. FAQ: Expert Technical Support
Q: Why does the 1/4" cutter have a 6mm shank instead of a 1/4" shank?
A: This is our hybrid design. 1/4-inch is exactly 6.35mm. If a European machinist only has 6mm or 7mm collets, a 6.35mm shank will not fit properly and will wobble. By turning the shank down to exactly 6.0mm, it fits perfectly into a standard metric 6mm collet, allowing the machinist to cut a flawless imperial 1/4" hole without tool runout.
Q: Can I use a hand tap wrench to turn these?
A: Technically yes, but it is not recommended. Hand reamers usually have a square drive on the end to lock into a wrench. These have perfectly round cylindrical shanks (designed for machine chucks). If you try to turn them with a hand wrench, the round shank will likely slip under heavy torque.
Q: Are these suitable for through-holes or blind holes?
A: Straight flute reamers are ideal for through-holes (where the chips can fall out the bottom). If you are using them in a blind hole (a hole with a solid bottom), you must peck-drill (frequently withdraw the tool) to clear the packed chips from the flutes, or the tool will bind and break.
