Router Bits Guide - Flipbook - Page 41
ROUTER BIT GLOSSARY
A) Axis – This refers to the path a CNC will travel (typically X,
Y, Z). X and Y refer to the side-to-side and front-to-back
cuts and Z refers to up and down (depth of cut). This is
crucial in a CNC, as it determines all the directions that
cuts are made.
B) Ball Nose – A spiral bit with a rounded nose that is used
primarily for carving or rounding corners. (See page 3)
Bearing (ball bearing, pilot bearing) – A sleeve, containing ball bearings, that rides along the edge of the
workpiece, or the template, guiding the cutting edges
along the templated path. (See page 39)
Bead – A convex (outward curve) profile used in moldings. This is similar to a round-over, but with small “steps”
above or below the profile. (See the graphics on page 15)
Bevel – A sloping or angling of the edge of the workpiece. (See page 16)
Bottom Bearing – With the shank end pointing upward, the bearing will be at the bottom of the flutes or
cutting edges. (Example: Flush Trim bits on page 17)
Braze – The method used to attach the carbide tips to
the bit body. Brazing is the joining of two closely fitting
pieces of like or different metals using a high-strength
compound. KLINGSPOR bits have a much better brazing
process than our competitors. It consists of 50% silver
& 50% Cobalt & Tungsten (no cheap fillers in the metal
mixtures). This is a very high-strength ratio of brazing
materials.
C) Carbide – A mixture of metals & powders heated and
mixed together to create a very hard, dense metal compound. The hardness of the carbide allows it to be honed
and sharpened to very accurate shapes and contours
while maintaining a long-lasting cutting edge.
(carbide-tipped bits) a machined steel body with carbide pieces brazed onto specific areas that make up the
cutting portion of a router bit.
(solid carbide bits) A bit formed (milled) entirely of
high-quality carbide.
Carving Liner - A solid carbide bit that produces an extra fine vein for detail carving or lettering. (page 3)
Chamfer – A symmetrical angle cut at the edge or corner of the work piece, most commonly at 45°. (Page 16)
Chip Breaker – An edge design that helps to break up
the chips into smaller pieces for more efficient evacuation
from the cut path. (See page 5)
Chip load – the thickness of a chip (waste), which is
formed during the machining of material. The chip load
is important because the proper size chip will carry away
heat, promoting long tool life. Speed and feed rate are
crucial factors. (See page 40)
Climb Cut – A climb cut refers to cutting the workpiece
in the opposite direction from the standard in small increments. This is done when using wild-grained wood
that is easily splintered. Typically, a router bit is designed
to efficiently and safely cut counter-clockwise along the
outside edge and clockwise on an inside edge. Imagine
a mirror frame. There is an outside portion and an inside
portion (where the mirror is).
CNC (computer numeric control) – A computercontrolled cutting or routing mechanism that can be
programmed to follow a strict cutting path, whether
it be cutting pieces to a specified dimension or carving
intricate designs on the surface of a piece. CNC routers use
a large variety of router bits to perform various operations.
Collet – A metal band or collar that the router bit’s shank
is mounted into on the spindle of a router or CNC router.
Standard sizes are 1/4", 3/8”, 1/2", 5/8”, & 3/4". Metric
sizes include 8mm, 10mm, and some others, but are not
usually found in the U.S. (See page 34)
Compression or Up/Down Spiral– Spiral bits that
combine down shear and up shear angles for an excellent surface finish on both top and bottom surfaces. It
“compresses” the top and bottom of the material towards
the middle. Because of the dual direction of the cut, the
chips are forced into the middle of the bit which provides
a clean cut on the top and bottom edges of the workpiece. Normal compression bits have a 3/8” up-cut, while
mortise compression bits have a 1/4" up-cut for making
shallow first passes. (See page 6)
Cope & Stick – This refers to rail & stile bits that make
the frame of a cabinet door. One bit makes the end of
the rails (top and bottom pieces) and the other makes the
inside of the rails and stiles (sides). The profiles are mirror
images of each other, so they fit perfectly when mated
together.
Cove – A concave cut (an inward curve) made on the
edge of the workpiece. (See page 13)
Cut Diameter (CD) or Cut Edge Diameter (CED) –
the diameter of the cutting portion of the bit when it has
made a complete circle.
Cut Length (CL) or Cutter Edge Length (CEL) – The
length of the cutting portion of the bit from top to bottom.
D) Dado – A groove cut into the face of a board into which
another board is inserted and fastened. (Page 9)
Diameter (D) – The measurement referencing the
size from one side to the other (imaginary line straight
across).
Dovetail - A bit that is tapered at specific degrees (7, 8,
9, 10, 14, etc.) to create attractive and structurally functional joints on wood. Typically used on drawers or boxes.
Down cut (down shear) – The bit has a downward
cutting action, pushing the chips “down” and away from
the router motor, leaving a clean cut on the top edge. This
configuration provides downward pressure during the cut
and aids in holding down the material being cut.
E) Edge Banding – A finished edge that is installed on the
raw edge of a plywood panel that makes the plywood
look more like a solid wood edge.
F) Feed Rate – The distance, in inches, or sometimes meters, per minute, that the bit will travel while cutting the
workpiece.
Figuring Feed Rate – To calculate the feed rate, multiply the recommended RPM by the number of flutes, and
then multiply that product by the recommended chip
load.
Feed Rate = RPM X # of flutes X chip load
Finger Joint – A strong joining configuration where
numerous “fingers” interlock with each other creating a
strong structural joint.
Flush Trim – Straight cutting bits that include a pilot
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41
G)
H)
K)
L)
M)
bearing on the end for trimming the workpiece flush to
a predetermined edge.
Flute – a single cutting edge on a router bit. A router bit
may have one or more flutes.
Single Flute – Use this configuration for faster feed
rates in softer materials. The single flute cutter typically
has more room for the chip ejection process to take place.
However, feed rates and the hardness of the material you
can cut, are limited by the single cutting edge. Plastics
and non-ferrous metals are prime candidates for singleedge cutters.
Double & Triple Flute – These bits provide better
finishes in some of the harder materials. Double-flute
bits provide a smoother cutting action due to a smaller
chip being produced. Triple-flute bits will give an even
smoother performance as the chip size is decreased even
more. These bits will leave a smoother cut edge on the
workpiece but feed rates will decrease, proportional to
the chip size.
Gullet - The cutout area in the body of the bit in front of
each flute, that allows for chip removal.
Helix Angle or Hook Angle – The angle of the cutting
edge of the flute.
Hinge-Boring Machine – A machine that uses both a
hinge boring bit to bore the cup portion of the hinge in
a door, but also dowel drills to bore the pilot holes for the
hinge screws. BLUM is one of the most common brands
of line/hinge boring machines.
Kroma coating – A nano-ceramic coating that, when
applied to the carbide, increases the hardness of the cutting edge, and increases the bit’s lubricity, causing it to
run cooler and with less friction. This increases the life of
the bit to 2-3 times the life of an uncoated bit. The Kroma
coating alternates between a blue and purple color. When
using o-flute bits, the Kroma coating is more suited to
plastics and composites. But will cut non-ferrous metals
and composites, as well. When used on a compression
bit, it is a longer-lasting alternative to solid carbide bits.
Laminate – Sometimes called plastic laminate, this
countertop covering is made from chemically treated
compressed layers of paper and finished with a durable
resin top coat in numerous colors and patterns. This material is sometimes incorrectly called “Formica”, which is
actually a brand name for the Formica company, who
manufactures plastic laminate countertop covering.
Line-Boring Machine – A machine that bores holes
in a straight line for adjustable shelving in the side panel
of a cabinet. This is done before the cabinet is assembled
and involves multiple router bits in a line. Machines range
from 5 bits to upward of 27 bits. There will always be odd
numbers of bits and the machine will require both right
and left-hand turning bits.
Lock Collar – A collar with a set screw that holds a bearing in place on the shank of the router bit.
Miter – An angle cut on the end of a workpiece that is
usually joined with another piece with a matching angle.
MDF – Medium Density Fiberboard. Used extensively
in cabinet construction. This man-made wood product
is made of medium-sized wood fibers. It works great for
parts that will require a painted surface.
ROUTER BITS
