Cutting Tool Steel

[Anonymous]

I finally got around to trying this. I used an uncoated carbide Garr 10mm 3 flute endcutting endmill. The cutter isn’t new by any means. The material used was a piece of new 5/16″ square HSS from a model engineering supplier; so god only knows what it actually is! I did two trials at differing speeds and feeds. In both cases I cut dry and cut the full width of the material with a depth of cut of 0.5mm.

 

1. First, I tried 600rpm and a feedrate of 50mm/min. This equates to a surface speed of 62ft/min and a chip load of 0.0011″. The cut worked, but the mill (Bridgeport) clearly wasn’t thrilled, as there was a hint of vibration. The finish looks ok, if a bit uneven. The Ra measures as 0.86µm.

 

2. Second, I tried 2500rpm and feedrate of 150mm/min. This equates to a surface speed of 258ft/min and a chip load of 0.0008″. The mill was happy with the cut, no detectable vibration, and as a bonus there was a rather pretty circle of orange light around the cut with tangential shafts of orange coming off, just like a Catherine wheel. The finish looks good, and the Ra measures as 0.26µm.

 

My hardness tester is in a state of dis-assembly, so I haven’t been able to make before and after hardness measurements.

 

Best Regards,

 

Andrew

[Ian S CParticipant @iansc]

I was looking for some information on some cast iron, and got into a site for carbide cutting tools, thes included some called Omega-6 M70, specially designed for HSS and other tool steels.

The same site offered a sharpening service for end/ slot mills, carbide burrs, drills, down to 3 mm. Only thing is, I forgot to note the name of the site, not that I’ll be needing the service. Ian S C

[Author]

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