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Countersinks
A countersink is a cutting tool which puts a conical hole into an object. A common use is
to allow the head of a countersunk bolt or screw, when placed in the hole, to sit flush with
or below the surface. Countersinks may also be used to remove burrs left from drilling or
tapping operations. Countersinks have been around for many years - from early jewelry
making to countersinking detonar holes to be filled with hand grenades during WW1.
Champion offers a variety of high speed steel countersinks for chatter free
performance, with smooth and fast chip removal. Countersinks can be used in
many tools such as hand held drills or drill presses, milling machines and lathes.
They are effective cutting many materials including metal, plastic and wood and
are ideal for the glass and window industry.
Most Popular Countersink Types
ZERO FLUTE COUNTERSINKS
Champion’s zero-flute countersink is a cross-hole countersink,
commonly referred to as a Weldon Style countersink. This is a
cone shaped tool with a cutting edge provided by a hole that
goes through the side of the cone. The intersection of the hole
and cone form the cutting edge of the tool.
Zero-flute countersinks are best used as deburring tools and
for countersinking softer materials such as aluminum, wood
or plastic to create a countersunk hole for a screw.
Zero countersinks come in 2 styles: Piloted and Pilotless.
(insert here what the pilot does?!?!)
SINGLE FLUTE COUNTERSINKS
Piloted HSS
• Piloted countersinks
are recommended for
screws from 1/4” to 1/2” diameter. (Round shank - CSK 82º)
Pilotless HSS
• Pilotless countersinks
are recommended for
bolt sizes from .073 to 1-15/32 and screw sizes #4
through #10.
(Round shank - DCB 60º, CSK 82º, DBK90º, CSKA100º)
(1/4” Hex Shank - CSK-SH)
• XL801 - Single flute
countersink
High hook
60º/82º/90º/100º/120º
Single flute countersinks are designed for use when multi-flute
countersinks chatter or the hole is too small for a multi-flute
countersinks to enter. Used for machine and portable work when
perating at high speeds.
• 799 - Three flute
THREE AND FOUR FLUTE COUNTERSINKS
countersink
60º/82º/90º/100º/120º
As with the single flute countersinks they are designed for
chatter free performance and are mostly in portable applications.
COMBINED DRILL & COUNTERSINKS
• 798 - Plain style drill
& countersink
HSS / 60º angle
Combined drill and countersinks (Champion #798,
796) are designed to produce accurate conical holes
in components which require machining between
centers.
• 796 - Bell style drill
& countersink
HSS / 60º & 90º angles
HOW TO CHOOSE THE RIGHT SIZE COUNTERSINK (DIAMETER)
A simple rule of thumb is to choose a countersink which is larger than the bolt size of hole. Countersink diameter = 1.5 x Bolt Size (hole) diameter.
Example: For a 1/4-20 bolt, multiply the diameter (.250) x 1.5 = .375. This equates to a 3/8” countersink.
HOW TO CALCULATE COUNTERSINK SPEEDS
Countersinking is usually performed at 1/3 the RPM of drilling. First calculate drilling speed by using the formula below. Then simply divide by 3.
Formula: SFM (surface feet/minute) x 3.82 / Cutter Diameter (decimal equivalent) / 3
Material
Surface Feet / Minute (SFM)
Aluminum
Mild Steel
Stainless Steel
Sample Calculations for 1/4” Countersink Speed (RPM)
200 - 250
100 - 110
30 - 100
(225 (SFM) x 3.82 / .2500) /3 = 1,146 RPM
(115 (SFM) x 3.82 / .2500) /3 = 586 RPM
(65 (SFM) x 3.82 / .2500) /3 = 381 RPM
* We recommend BruteLube to enhance performance and extend tool life for all cutting tools.
For more information please contact our Customer Service Department at 516-536-8200
or visit our website at www.championcuttingtool.com