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   DRILL BIT TERMINOLOGY To drill a satisfactory
hole in any material, the correct type of drill bit must be used; it must be used correctly and be sharpened as appropriate.
Many jobs around the house require a hole of some kind to be drilled - whether it is putting up a shelf, building
a cabinet or hanging a light fitting. For basic requirements, a set of high-speed steel twist drills and some masonry
bits will probably be sufficient for the average handyman. But for more sophisticated jobs/material, others bits will be required
- perhaps larger, or designed for a specific material/purpose. Good quality drill bits can be expensive, so take
care of them, keep them in a case or box if possible, rather than allowing them to roll around loose in a toolbox where the
cutting edges may be damaged. Learning how to sharpen drill bits is cost effective, it better to keep a bit sharp
by occasional sharpening rather than waiting until it becomes really blunt. A sharp bit cuts better with less effort whether
used in a power or hand drill. A sharp bit will also give a cleaner hole. Twist bits Usually referred
to as twist drills, twist bits are probably the most common drilling tools used by the handyman with either a hand or electric
drill. The front edges cut the material and the spirals along the length remove the debris from the hole and tend to keep
the bit straight. They can be used on timber, metal, plastics and similar materials. Most twist bits are made from
either: high speed steel' (HSS), these are suitable for drilling most types of material, when drilling metal
the HSS stands up to the high temperatures. 'carbon steel', these bits are specially ground for drilling wood and should not be used for drilling metals, they tend to be more brittle, less flexible than HSS bits. Twist bits
are also available coated with Titanium nitride (TiN), these are easily identified by the gold like colour. This coating increases
the hardness of the bit and adds a self-lubricating property. The coating is only really effective when metal is being drilled,
it has little effect when working with other materials. Twist drills are usually available in sizes 0.8-12 mm plus.
They are designed for drilling relatively small holes, they sometimes tend to clog quickly especially when the wood is 'green'
so when drilling deep holes (especially in hardwood) the bits should be withdrawn regularly to remove the waste. Special
care is required when using the smallest sizes since these bits are thin and brittle. Always hold the drill square to the
work and apply only light pressure when drilling. Sharpening - use a drill sharpener, a grindstone jig or an oilstone.
Titanium nitride bits cannot be sharpened without destroying the coating (although if the drill needs sharpening,
the coating will probably have already been destroyed). Forming the correct angle at the tip is important for efficient cutting.
Screwdriver bit drills Designed to fit in rechargeable screwdriver these bits have a hexagonal shank.
They are ideal for drilling pilot holes but are limited by the low power of these type of screwdrivers and the limited size
of small bits available. Sharpening - as for twist drills. Masonry bit As the name suggests,
these are designed for drilling into brick, block, stone, quarry tiles or concrete. The cutting tip is often made from tungsten
carbide bonded to a spiralled steel shaft. Some masonry drills are described as 'durium tipped', this term refers
to a highly durable silicon bronze alloy used instead of tungsten as the cutting point. Masonry drills are usually
used in a power drill; although they can be used with a lot of effort in a hand brace. Most masonry bits can be used with
a hammer action power drill, but always check as the action is quite punishing on the bit and cheaper bits have been known
to shatter when subjected to the pounding. Always use a slow rotational speed for drilling into harder materials to avoid
overheating the tip, and frequently withdraw the bit to remove dust. Long Masonry bits (300 to 400mm) are available
for drilling through masonry walls. Bit sizes range from 4 to 16mm. Sharpening - use a drill sharpener
or grindstone to sharpen the tungsten carbide tip. Spur point bit Also known as a wood or dowel bit,
they have a central point and two raised spurs that help keep the bit drilling straight. The bit cuts timber very fast when
used in a power drill and leaves a clean sided hole. They are ideal for drilling holes for dowels as the sides of the holes
are clean and parallel. Sizes range from 3 to 10mm. Spur point bits should only be used for drilling wood or some plastics.
Sharpening - a bit fiddly as it has to be done by hand. Sharpen the point and spurs with a fine file or edge of
a fine grindstone; the angle between the point and spurs should be 90°. Bullet Pilot Point With
their central point and two spurs, Bullet drills resemble spur point bits, but can be used in metal, wood and plastics. Unlike
normal twist drills, the twisted flutes are ground away; making a truer, more accurate bit than normal twist bits. They cut
a clean hole and cause little damage when they break through the back of the workpiece. Bit sizes range from 1.5
to 13 mm. Sharpening - cannot be carried out satisfactorily. Countersink Although not a true
'drill', it is used in a power or hand drill to form the conical recess for the heads of countersunk screws. These
bits tend to be designed for use on soft materials such as timber and plastics, not metals. When used with a power drill to
counter sink an existing hole, the bit tends to 'chatter', leaving a rough surface. Better results be will obtained
if the countersink bit is used before the hole is drilled, then take care to ensure that the hole is in the centre of the
countersunk depression. Countersinks are available with fitted handles so that they can be used by hand twisting,
often easier than changing the bit in the drill when only a relatively few holes need countersinking. Sharpening:
difficult, but can be done with a fine triangular file. Countersink with clearance drill These combination
bits are quite clever, they drill the clearance hole and countersinks it all in one stroke. Can be used in a power drill or
some routers. Different bits are required for different size of clearance holes and they are probably not cost effective unless
a large number of a given hole size need to be drilled and countersunk. Sharpening - difficult, due to shape of
spur points. Tile Bit A bit for drilling ceramic tiles and glass, it has a ground tungsten carbide tip.
They can be used with a hand drill, but are best used in a variable speed power drill on a slow speed. When drilling glass,
some form of lubricant (i.e. turpentine or white spirit ) should be used to keep the tip cool. Ceramic tiles can
also be drilled using a masonry bit if it is used at slow speed and without hammer action. Sharpening - difficult
because of the hard tungsten carbide and curved cutting edge. With care and patience, a blunt edge can be made good using
an oilstone. Flat wood bit Intended for power drill use only, the centre point locates the bit and the
flat steel on either side cuts away the timber. These bits are used to drill fairly large holes and they give a flat bottomed
hole (with a central point) so are ideal where the head of a screw/bolt needs to be recessed into the timber - always use
this bit before drilling the clearance hole for the bolt. The larger bits require a fairly powerful drill to bore
deep holes. The bits cause a lot of splintering as they break out the back of the workpiece - using a sacrificial backing
board will reduce this. Flat wood bits are not really suitable for enlarging an existing hole. Sizes range between
8 and 32mm. Sharpening - use a fine file, oilstone or grindstone. Hole saw Used for cutting
large, fixed, diameter holes in wood or plastic. They will usually cut up to a depth of 18mm - deeper versions are available.
Best used in a power drill at low speed as the blade saws it's way through the material. Sharpening - could
be done with a fine triangular file - as for an ordinary saw. Combination hole saw Like the Hole Saw
above, these combination saws can cut large holes but they consist of a number of different sized round saw blades, usually
ranging from about 25 to 62mm in diameter. Normally the blade are secures by a radial screw in the 'head', all blades
other than the desired sized being removed before the screw is inserted to secure the required diameter blade. Best used in
a power drill at low speed as the blade saws it's way through the material. Sharpening - could be done with
a fine triangular file and 'setter' as for an ordinary saw. Forstner bit Used to form holes
with a flat bottom, such as for kitchen cupboard hinges. Best used in a power drill held in a drill stand as there's little
in the way of a central point. If used freehand, the positioning is difficult to control as there is no central pilot bit.
. Sharpening - on an oilstone or with a fine file. Wood Auger bit This is ideal when drilling
large-diameter, deep holes in wood or thick man-made boards. Generally an Auger bit should only be used in a hand brace. The
bit will cut a clean and deep, flat bottomed holes. The single spur cuts and defines the edge of the hole while the chisel-like
cutting edge removes the waste within the previously cut circle. The threaded centre bites into the wood and pulls the bit
into the timber. This 'pulling' action means that the bit is really unsuitable for use in a power drill. Sharpening
- use a fine file or oilstone to keep the spur and main cutting edges sharp.
    CIRCULAR SAW BLADE CHARACTERISTICS AND TERMINOLOGY Below
is a list of terms to assist you in selecting the right blade for the right job: Anti-kick: A shoulder
design that is engineered to improve the ease of cut and reduce the effect of the saw blade kicking back due to overfeeding. Arbor: The saw motor shaft that rotates the saw blade. Often refered to as the mandrel. Bore:
The arbor by which the saw blade is mounted on the saw. Available in various sizes. Bevel: Angles on a carbide
tooth blade. Teeth can have a single bevel, double bevel or no bevel at all. Types of bevels can alternate from tooth to tooth on a given blade. The bevel is what gives the blade its specific cutting pattern. Chipper: A cutting
tool that is placed between the outside blades of a dado set to adjust the width of the cut. Chipping: A condition
caused when the saw blade lifts and tears the wood fibers as it exits the material. This causes the edges to be ragged. Coating: Specially fomulated coatings that stays slick. Coating a blade reduces heat in two ways: It minimizes
friction and binding and resists pitch and gum buildup. Combination saw blade: A blade used for both ripping
(cutting with the grain of the wood) and crosscutting (cutting across the grain). Crosscut: To cut or saw
against of the grain of the wood. Cutter: Outside blades used in dadoes. Dado: A flat-bottomed
recessed cut made across the grain of a board. Also, a set of blades used to produce precision grooves. Dyanite
Carbide®: A Vermont American proprietary carbide formulation that adds fracture toughness and allows up to 5 times edge retention compared to conventional carbide. Expansion slots: The spaces that allow a blade to expand
as it heats up during cutting. It eliminates warpage by cooling the blade. Ferrous: Of or containing iron.
Finishing saw blade: A saw blade with a higher tooth count to provide smoother cuts. Typically refers to 7-1/4" blades with more than 40 teeth and 10" blades with more than 60 teeth. Framing saw blade: A carbide tipped
blade used to make fast cuts inall types of wood. (The fastest cutting is achieved with lower tooth count
saw blades.) General purpose saw blade: A saw blade with a lower tooth count. Used primarily for fast crosscutting and ripping. Gullet: The space between teeth that clears the workpiece of chips after the cut. Grind: There are many types of tooth grinds, a few of the basic ones are: Hollow ground: A concave bevel edge on a tool. Hook angle: The “attack angle” of the teeth. Harder, more brittle materials need a shallower angle to ease pressure against the materials and reduce chip out. Softer materials require a sharper angle to reduce chip out. Kerf: This is the width of a cut, including the steel plate thickness plus any overhang on a carbide blade. Miter: The process of cutting material for an equal angle joint. Nonferrous: Materials and metals not of or containing iron, such as aluminum, copper, brass and lead. Plate: The steel body of a carbide blade on which the teeth are welded. Plane: In woodworking, to make a surface smooth or even. Rabbet: An open-ended cut made along the edge of a workpiece that receives or interlocks with another piece to form a joint. Ripping: The process of sawing a board in the direction of the grain of the board. Runout: The amount of left-to-right movement a saw blade makes during operation. Often referred to as wobble or warp. Stiffening collar: A flat collar that mounts on a saw’s arbor directly next to the blade. It is used to make more accurate cuts and dampen the sound the saw generates. Shim: A thin, often tapered piece of material such as metal or wood used to fill in space between things. In dado operations, a round disk used to make a wider cut. Tear-out: A condition in which the saw blade tears out the grain of a workpiece. Tempered: To bring the steel plate of a saw blade to a desired
MORE TEETH, CLEANER CUT Here’s a suggestion
for cutting plastic, veneer or laminates with your table saw: use a blade featuring a triple chip grind (TCG) tooth design,
and opt for a blade with a higher tooth count. The TCG tooth design and higher tooth count reduces cracking on the workpiece.
Visit the Knowledge Center to see Circular Saw Blade Terminology, including descriptions of various tooth configurations.
After extended use in gummy or sticky wood, a circular saw blade can become coated with wood pitch. Pitch
buildup causes the blade to drag, which can burn some hard woods. To clean the bit, fill a shallow metal pan with just enough
pitch solvent or de-natured alcohol to cover the blade. You MUST place a cover on the container, as solvents are flammable.
Soak overnight. Use a soft brush, such as a toothbrush, to get rid of any remaining residue, then wipe clean with a rag. The
materials from which saw blades are manufactured play a big role in the life and performance of the blade. Steel
Blades— inexpensive and work well for cutting softwood. Steel blades dull quickly in hardwood. High-Speed
Steel (HSS) Blades— harder than steel blades and stay sharp longer. Carbide-Tipped Blades— more expensive
than steel and HSS blades, but they stay sharp much longer than steel or HSS. Abrasive Blades— bonded abrasive
materials used for cutting masonry and metals. Diamond Blades— diamond tipped teeth and are usually used to
cut glass, concrete and ceramic materials. Safety Notes: Always follow the saw manufacturer's instructions for the saw blade diameter. Ripping Use for cutting with the wood grain Have few teeth and a large
gullet for good chip removal
Crosscutting Use for cutting across the wood grain Have many teeth (48 or more) and a small gullet for a smooth cut Combination Use for cutting with or across the grain and miter cuts Usually have a series of four to five teeth similar to a crosscut divided by a large gullet Plywood Use for cutting plywood or other sheet goods Usually made from HSS with many fine teeth (100 or more) Hollow Ground Use for making smooth cuts across the wood grain. Ground thinner in the body than the teeth to prevent binding Dado Use for cutting grooves and dados in dimensional lumber and sheet goods Manufactured as stacked, one-piece or two-piece adjustable units Thin Kerf Use for cutting dimensional or engineered lumber Have thin profiles for easier cutting and less material waste Abrasive Use for cutting masonry, tile or steel Compatible with most circular saws of the same diameter as the blade Diamond Use for cutting glass, concrete or ceramic materials hardness by reheating and cooling. Thin kerf saw blade: A saw blade with a reduced kerf, or cut width. SDS SPECIAL DIRECT SYSTEM
What is an SDS Hammer Drill?Special Direct System. Normal hammer drills need to move the whole drill chuck to apply the hammer action. SDS drills allow the bit to move inside the chuck, allowing power to be directed more accurately and efficiently, which results in better performance drilling through substances such as concrete. What
are the benefits of an SDS drill over a normal Hammer Drill? Drilling modes Hammer Only Also called “roto stop”. You can fit a range of SDS chisel bits and use the drill like a micro concrete breaker. Ideal for light demolition, removing tiles, bricks, and creating socket cut ins or cable runs. Not all products will have this mode. Drill and Hammer Drill mode with the hammer action. SDS hammer drills can be quieter than conventional SDS hammer drills, despite the extra performance. Beneficial Features 2kg is an ideal weight for a drill that is used regularly. 4kg+ drills will be ok if you only use them occasionally, but long periods of use will be harder to work with. Low end budget drills tend to be heavier. Decent speed control will allow you to be more careful entering and exiting substances. Rotation lock allows you to lock the rotation of the drill, so that if you want to chisel into substances, it will not rotate. This is essential if you want to use the drill in hammer mode to chisel accurately. Note SDS drills give the maximum drill bit diameter in the title, such as 1 Inch, or 1 1/8 inch. Bigger drill bit diameters will fit, but will be underpowered.
SDS drill bits are inserted by pushing the bit into the chuck, and held in place by grooves in the bit. No tightening is needed as each bit is designed to fit the chuck exactly. The open grooves allow a rotation action to be applied, whilst the closed grooves allow the hammer action by using ball bearings to lock the bit in place. It is impossible for the drill bit to slip out of place. They are taken out of the drill via a lock release mechanism. The bit actually hammers back and forth within the chuck. This is why SDS hammer drills deliver more powerful than regular hammer drills. In regular hammer drills the whole chuck needs to move, which wastes power and is less efficient. SDS drills give the maximum drill bit body diameter in the title, such as 1 Inch, or 1 1/8 inch. Bigger drill bit diameters will fit, but will be underpowered. The shank diameter of SDS drill bits need to be the correct size for that type of SDS drill.
Different types of SDS drill bits SDS plus SDS plus drill bits have 4 grooves (2 open grooves, 2 closed), and can be used in regular SDS drills or SDS plus drills. The reason that SDS plus drill bits have 4 grooves is to support to extra torque that the SDS plus drill provides. They have a 10mm shank which is inserted 40mm into the chuck. They can be used in SDS hammer drills up to around 4kg in weight. SDS-top A 14mm shank inserted 70mm into chuck. Designed for drills of up to 5kg, very similar to SDS plus drill bits but less popular. They are only compatible with SDS-top drills. SDS max SDS max is a more heavy duty industrial drill than SDS plus, and in general have SDS drill bits that have larger body diameters. The shank is 18mm, with 3 open grooves, and is inserted 90mm into the drill chuck. SDS max drill bits are not compatible with SDS or SDS plus drills, or vice versa. You will need adapters to use SDS or SDS plus drill bits in an SDS max drill. Spline Spline drive drills do not use the SDS system, but provide similar performance to SDS max, although the bits are not compatible. You will need Spline drive drill bits to use in a Spline drive drill. Adapters are available to use Spline drive bits in an SDS max drill and vice versa.
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