Countersinks, Reamers & Burs

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Expected delivery: Wed, Nov 18

These tools finish a hole or edge after drilling. Countersinks cut a cone so flat head screws sit flush and also break sharp edges. Reamers bring a drilled hole to an exact size with a smooth finish for pins, bushings and shafts. Carbide burs shape, deburr and port metal in a die grinder. This section includes single flute, multi-flute and zero flute countersinks, chucking reamers, hand reamers and adjustable reamers, carbide burs in common shapes and cuts, and hand deburring tools.

What to check before you order

  • Countersink angle. Match the screw head. Inch flat head screws generally use 82 degrees, metric flat heads use 90 degrees, and some aircraft fasteners use 100 degrees.
  • Reamer allowance. Drill the hole slightly under the finished size before reaming. Reamers remove only a small amount of stock.
  • Bur shape and cut. Cylinder, ball, tree and flame shapes reach different areas. Double cut burs leave smaller chips and a smoother finish on steel. Single cut suits hard steel and general stock removal.
  • Shank and speed. Most burs have a 1/4" or 1/8" shank. Stay within the bur maker's speed rating and wear eye protection.

Browse drill bits, end mills and inserts, Alfa Tool countersinks and reamers, or all cutting tools.

Common questions

What is the difference between a chucking reamer and a hand reamer?

A chucking reamer runs in a drill press, lathe or mill at reduced speed. A hand reamer has a square end for a tap wrench and a longer tapered lead so it can start straight by hand.

Can carbide burs be used on aluminum?

Yes, but standard cuts can clog with soft metal. Aluminum-cut burs have coarse, widely spaced flutes that clear chips better on nonferrous metals. Follow the bur maker's speed guidance and wear eye protection.

Countersinks, Reamers & Burs: page 10

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