Features and Terms

What to know

Material and hardness

M2 high speed steel hardened to a hardness of 63 RC

Available cutter diameters

7/16” to 2-1/16”

Below 7/16” the cutter bore is minimal and the material removed during the drilling cycle is similar to that of a twist drill. A general rule of thumb is the larger the centerfree cutter the greater the advantage in time savings over conventional twist drills

Depth of Cut

Available in one-, two-, three-, and four-inch drilling depth

Example: Our one-inch depth annular cutters are capable of drilling a true one inch thickness when new.

Resharpenable

Annular cutters can be resharpened indefinitely. Each sharpening removes approximately 1/64” from the cutters over all length. This means that a one-inch depth cutter will not be able to drill a true one-inch thickness after several sharpens. However most common structural materials are less than ¾” thick.

Resharpen Cost

Refer cost sheet (coming soon )

Typically the cost is associated to the diameter

Tool Life between resharpening

With proper use on mild steel approximately 250 to 300 inches between resharpening.

Factors that vary tool life include RPM, feed pressure, coolant usage and type, material to be drilled, operator, drilling position and resharpening

Geometry

7/16” to ¾” equal teeth all with the same geometry

13/16” to 2-1/16” alternating teeth with different geometry

We offer two geometrys to compensate for cutting RPM surface cutting speed and diameter changes. Smaller cutters turn faster, create fewer chips, larger cutters cover much more of the material surface and create much larger chip nests, our two unique geometry’s allow both small and large diameter cutters to achieve top performance.  

Hole Tolerance

Cutter diameter to +.005

This may vary depending on the spindle run out of the machine being used

Wall Thickness

The width of fluted area

Commonly drilled materials

A36, A536, A572 1018 in hot and cold rolled

 Materials with RC lower than 29RC

Harder Material to drill

Titanium, Inconell, Stainless, Flame cut material, work hardening materials, materials with RC higher than 30RC

Harder material require slower RPM and mean reduced cutter performance. If a standard high speed steel cutter can not drill the material a centerfree will not be able to drill the material

Pilot

¼” pilot diameter

Pilot features a small slot down the side, which allows coolant to flow down pilot to center of cutter. When the pilot is in the full upright position coolant flow is stopped. Directly interchangeable with Jancy Slugger, Universal, Unitec, Unibor. Not with Hougen Rotobroach

Pilot Functions

Cutter drive shank

One large flat for securing cutter to arbor

Drilling Action

Chip Nesting

The nest of chips that forms naturally around the cutter

Results from the continuous material removal and multiple cutting edges. After the cut remove cutter from hole and reposition cutter over open area. Lower cutter to bottom of machine stokes. Using a long handle screwdriver type tool force chips counter clockwise and downward off cutter.

Surface Coatings

TINI and TICN

Surface coatings increase the surface RC approximately 20RC, aid in chip removal and help prevent heat damage to the steel underneath the coating therefore prolonging cutter life. The use of coatings should be considered when drilling harder material, when normal coolant flow is not an option, or when drilling gummy materials such as aluminum. Cost is added to the retail price of the cutter and it should be noted that the coating should be reapplied after each sharpening.

Coolant

Water soluble diluted with 10 parts water

Coolant should always be supplied through the center of the cutter when ever possible. Applying coolant to the outside of the cutter does very little to coolant to cutter.

Slug

The material that is not machined

Ejects after the cut and is disposed of as a solid. Failure to use coolant properly allows the slug to heat and expand causing slug ejection problems.

ID Sharpening

Drilling Multiple Plates at the same time

Is slug must be removed between layers or the cutter geometry must be modified to allow continuous drilling. This modification is referred to as ID sharpening. Cutter life is decreased when drilling with ID sharpened cutters.

Center Free Drilling

Drills from the outside edge

Requires no center drilling, multiple edges create milling action. Cutters also work well on rounds, tubing, and irregular shapes. Existing holes can be elongated and semicircle may be formed.