3 5 and 6 Flute Corner Radius
High-performance carbide end mills with a corner radius replace the sharp 90° corner of a square end tool with a rounded one, spreading cutting forces across an arc instead of concentrating them at a single point. Stocked in 3 flute at 45° and 60° helix, 5 flute at 45° helix, and 6 flute in standard and long reach lengths.
Longer Edge Life: The corner is where a square end mill fails first. Rounding it removes the stress concentration that causes chipping and corner breakdown, which matters most in interrupted cuts, hardened steels, and heavy radial engagement.
Better Surface Finish: A rounded corner leaves a cleaner floor-to-wall transition than a sharp one, particularly in aluminum and plastics where a sharp corner tends to score the surface. It will often remove the need for a separate finishing pass.
Choosing a Radius: A larger radius is stronger and lasts longer; a smaller one leaves a tighter corner in the finished part. Match the radius to the largest the internal corners on your print will accept. The 3 and 5 flute ranges are stocked in 0.01", 0.02" and 0.04"; the 6 flute ranges in 0.02" and 0.04".
Helix and Flute Count: The 3 flute tools are offered at 45° and 60° helix. The higher helix shears more gradually for a smoother finish; the lower helix is more rigid for heavier cuts. The 5 flute option puts more cutting edges in the work for finishing passes, where chip clearance is less of a constraint.
6 Flute and Long Reach: The 6 flute ranges are ALTiN coated throughout and start at 1/4" diameter, trading chip clearance for cutting edges — best suited to finishing passes and lighter radial engagement in harder material. Both a standard and a long reach length are stocked, the long version reaching 6" overall for deeper cavities and pocket floors a standard tool cannot reach.
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Compare SKU Vendor Size (D1) Shank Diameter (D2) Flute Length (L2) Reach (L3) Overall Length (L1) Length Type Corner Radius (R) Included Angle Taper Angle Helix Angle Number of Flutes Weldon Flats Flats Coating In Stock Price Quantity A55369 ACT 1/8 1/8 1/4 1-1/2 0.01 45° 5 Uncoated 50 $12.08 -
A55338 ACT 1/8 1/8 1/2 1-1/2 0.01 45° 3 ALTiN 10 $26.80 -
A55330 ACT 1/8 1/8 1/2 1-1/2 0.01 45° 3 Uncoated Available to Order* $21.52 -
A55322 ACT 1/8 1/8 1/2 1-1/2 0.01 60° 3 ALTiN 23 $26.80 -
A55314 ACT 1/8 1/8 1/2 1-1/2 0.01 60° 3 Uncoated Available to Order* $21.52 -
A55378 ACT 1/8 1/8 1/4 1-1/2 0.01 45° 5 ALTiN 100 $14.59 -
A55339 ACT 3/16 3/16 3/4 2 0.01 45° 3 ALTiN 10 $31.91 -
A55323 ACT 3/16 3/16 5/8 2 0.01 60° 3 ALTiN 15 $31.91 -
A55315 ACT 3/16 3/16 5/8 2 0.01 60° 3 Uncoated Available to Order* $25.90 -
A55387 ACT 1/8 1/8 1/2 1-1/2 0.01 45° 5 Uncoated 50 $22.64 -
A55340 ACT 1/4 1/4 3/4 2-1/2 0.02 45° 3 ALTiN 30 $34.30 -
A55332 ACT 1/4 1/4 3/4 2-1/2 0.02 45° 3 Uncoated Available to Order* $27.70 -
A55324 ACT 1/4 1/4 3/4 2-1/2 0.02 60° 3 ALTiN 7 $34.30 -
A55316 ACT 1/4 1/4 3/4 2-1/2 0.02 60° 3 Uncoated Available to Order* $27.70 -
A55395 ACT 1/8 1/8 1/2 1-1/2 0.01 45° 5 ALTiN 37 $27.92 -
A55341 ACT 5/16 5/16 13/16 2-1/2 0.02 45° 3 ALTiN 11 $41.52 -
A55333 ACT 5/16 5/16 13/16 2-1/2 0.02 45° 3 Uncoated Available to Order* $33.48 -
A55325 ACT 5/16 5/16 13/16 2-1/2 0.02 60° 3 ALTiN 17 $32.12 -
A55317 ACT 5/16 5/16 13/16 2-1/2 0.02 60° 3 Uncoated Available to Order* $33.48 -
A55370 ACT 3/16 3/16 3/8 2 0.01 45° 5 Uncoated 50 $18.63 -
A55342 ACT 3/8 3/8 7/8 2-1/2 0.02 45° 3 ALTiN 23 $56.07 -
A55326 ACT 3/8 3/8 7/8 2-1/2 0.02 60° 3 ALTiN 9 $56.07 -
A55379 ACT 3/16 3/16 3/8 2 0.01 45° 5 ALTiN 50 $22.01 -
A55343 ACT 1/2 1/2 1-1/4 3 0.04 45° 3 ALTiN 19 $105.88 -
A55335 ACT 1/2 1/2 1-1/4 3 0.04 45° 3 Uncoated Available to Order* $88.52 -
A55327 ACT 1/2 1/2 1-1/4 3 0.04 60° 3 ALTiN 9 $105.76 -
A55319 ACT 1/2 1/2 1-1/4 3 0.04 60° 3 Uncoated Available to Order* $88.52 -
A55388 ACT 3/16 3/16 3/4 2 0.01 45° 5 Uncoated 50 $28.37 -
A55344 ACT 5/8 5/8 1-5/8 3-1/2 0.04 45° 3 ALTiN 9 $203.14 -
A55336 ACT 5/8 5/8 1-5/8 3-1/2 0.04 45° 3 Uncoated Available to Order* $180.10 -
A55320 ACT 5/8 5/8 1-5/8 3-1/2 0.04 60° 3 Uncoated Available to Order* $180.10 -
A55396 ACT 3/16 3/16 3/4 2 0.01 45° 5 ALTiN 29 $33.40 -
A55345 ACT 3/4 3/4 1-5/8 4 0.04 45° 3 ALTiN 10 $209.98 -
A55337 ACT 3/4 3/4 1-5/8 4 0.04 45° 3 Uncoated Available to Order* $252.70 -
A55329 ACT 3/4 3/4 1-5/8 4 0.04 60° 3 ALTiN 12 $280.24 -
A55321 ACT 3/4 3/4 1-5/8 4 0.04 60° 3 Uncoated Available to Order* $252.70 -
A55371 ACT 1/4 1/4 1/2 2 0.02 45° 5 Uncoated 50 $22.38 -
A55380 ACT 1/4 1/4 1/2 2 0.02 45° 5 ALTiN 100 $26.23 -
A55389 ACT 1/4 1/4 3/4 2-1/2 0.02 45° 5 Uncoated 50 $30.55 -
A55397 ACT 1/4 1/4 3/4 2-1/2 0.02 45° 5 ALTiN 13 $35.95 -
A55372 ACT 5/16 5/16 1/2 2 0.02 45° 5 Uncoated 50 $26.84 -
A55381 ACT 5/16 5/16 1/2 2 0.02 45° 5 ALTiN 100 $33.18 -
A55390 ACT 5/16 5/16 7/8 2-1/2 0.02 45° 5 Uncoated 50 $36.77 -
A55398 ACT 5/16 5/16 7/8 2-1/2 0.02 45° 5 ALTiN 14 $43.33 -
A55373 ACT 3/8 3/8 5/8 2 0.02 45° 5 Uncoated 50 $44.16 -
A55382 ACT 3/8 3/8 5/8 2 0.02 45° 5 ALTiN 100 $51.99 -
A55399 ACT 3/8 3/8 7/8 2-1/2 0.02 45° 5 ALTiN 19 $58.13 -
A55374 ACT 7/16 7/16 5/8 2-1/2 0.02 45° 5 Uncoated 50 $50.55 -
A55383 ACT 7/16 7/16 5/8 2-1/2 0.02 45° 5 ALTiN 18 $59.58 -
A55375 ACT 1/2 1/2 5/8 2-1/2 0.04 45° 5 Uncoated 50 $67.24 -
A55384 ACT 1/2 1/2 5/8 2-1/2 0.04 45° 5 ALTiN 100 $79.36 -
A55400 ACT 1/2 1/2 1-1/4 3 0.04 45° 5 ALTiN 61 $123.53 -
A55376 ACT 5/8 5/8 3/4 3 0.04 45° 5 Uncoated 50 $122.41 -
A55385 ACT 5/8 5/8 3/4 3 0.04 45° 5 ALTiN 17 $143.93 -
A55393 ACT 5/8 5/8 1-5/8 3-1/2 0.04 45° 5 Uncoated 50 $206.03 -
A55401 ACT 5/8 5/8 1-5/8 3-1/2 0.04 45° 5 ALTiN 8 $244.33 -
A55377 ACT 3/4 3/4 1 3 0.04 45° 5 Uncoated 50 $164.92 -
A55386 ACT 3/4 3/4 1 3 0.04 45° 5 ALTiN 18 $190.56 -
A55394 ACT 3/4 3/4 1-5/8 4 0.04 45° 5 Uncoated 50 $289.69 -
A55402 ACT 3/4 3/4 1-5/8 4 0.04 45° 5 ALTiN 7 $332.10
* Lead times can vary from 1–10 business days. Call (908) 98-ATLAS or email sales@atlascuttingtools.com for details.