|
Drill Bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole.
 
Buy Drill Bits in our online store
Discounted prices, same day shipping on stocked items!
Why use a Drill Bits
The twist drill bit is the type produced in largest quantity today. It drills holes in metal, plastic, and wood. 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 such as Cobalt Drill Bits to drill Stainless Steel and other hard metals and Granite Masonry drills to drill Porcelain Tiles.
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.
Types of Drill Bits
Masonry Drill Bits
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 spiraled 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.
Buy Masonry Drill Bits in our online store. Discount prices, same day shipping on stocked items!
Masonry Drill Bits Granite
Especially Suited for Drilling Marble, Granite, Porcelain Tile, Hard Metal, Plastic, Wood, Masonry. These bits makes holes in almost all materials! Engineered for drilling hard materials, these specialized Bits have a serrated carbide tip, which penetrates faster - up to 50% faster than standard masonry bits!
Buy Masonry Drill Bits Granite in our online store. Discount prices, same day shipping on stocked items!
HSS Drill Bits
Standard straight shank ground flute drills for general purpose application on steel and cast iron, alloyed and non alloyed, Grey cast iron, German silver steel, Graphite etc.
Buy HSS Drill Bits in our online store. Discount prices, same day shipping on stocked items!
Cobalt HSS Drill Bits
Cobalt drill-bits are the next step up the hardness scale from HSS drill-bits. They are designed to drill very hard materials, and will cope better with metals like stainless steel.
Buy Cobalt HSS Drill Bits in our online store. Discount prices, same day shipping on stocked items!
Drill Bit Performance
The geometry and sharpening of the cutting edges is crucial to the performance of the bit. Users often throw away small bits that become blunt, and replace them with new bits, because they are inexpensive and sharpening them is difficult. For larger bits, special grinding jigs are available. A special tool grinder is available for sharpening or reshaping cutting surfaces on twist drills to optimize the drill for a particular material.
Types of Drill Manufacturing
Manufacturers can produce special versions of the twist drill bit, varying the geometry and the materials used, to suit particular machinery and particular materials to be cut. Twist drill bits are available in the widest choice of tooling materials. However, even for industrial users, most holes are still drilled with a conventional bit of high-speed steel (HSS)
The most common twist drill (the one sold in general hardware stores) has a point angle of 118 degrees. This is a suitable angle for a wide array of tasks, and will not cause the uninitiated operator undue stress by wandering or digging in. A more aggressive (sharper) angle, such as 90 degrees, is suited for very soft plastics and other materials. The bit will generally be self-starting and cut very quickly. A shallower angle, such as 150 degrees, is suited for drilling steels and other tougher materials. This style bit requires a starter hole, but will not bind or suffer premature wear when a proper feed rate is used.
Drills with no point angle are used in situations where a blind, flat-bottomed hole is required. These drills are very sensitive to changes in lip angle, and even a slight change can result in an inappropriately fast cutting drill bit that will suffer premature wear.
Drill Bit Geometry
The spiral, or rate of twist in the drill: This controls the rate of chip removal in a drill. A fast spiral drill is used in high feed rate applications under low spindle speeds, where removal of a large volume of swarf is required. Low spiral drills are used in cutting applications where high cutting speeds are traditionally used, and where the material has a tendency to gall on the drill or otherwise clog the hole, such as aluminum or copper.
The point angle or the angle formed at the tip of the drill: This is determined by the material the drill will be operating in. Harder materials require a larger point angle, and softer materials require a sharper angle. The correct point angle for the hardness of the material controls wandering, chatter, hole shape, wear rate, and other characteristics.
The lip angle determines the amount of support provided to the cutting edge: A greater lip angle will cause the drill to cut more aggressively under the same amount of point pressure as a drill with a smaller lip angle. Both conditions can cause binding, wear, and eventual catastrophic failure of the tool. The proper amount of lip clearance is determined by the point angle. A very acute point angle has more web surface area presented to the work at any one time, requiring an aggressive lip angle, where a flat drill is extremely sensitive to small changes in lip angle due to the small surface area supporting the cutting edges.
The Mechanic Drills used widely by vendors to further describe the length of the drill itself: The actual length x diameter must be found and published. Most drills for consumer use have straight shanks. For heavy duty drilling in industry, drills with tapered shanks are sometimes used. Long series drills are extended length twist drills. They are not the best tools for drilling deep holes, as they require frequent withdrawal to clear the flutes of swarf and prevent drill breakages. Gun drills are the preferred drills for deep hole drilling.
Using a Drill Bit
First make certain the bit is the appropriate material for the material you are drilling. Select a bit designed for metal if you are drilling through metal and select a bit designed for wood when drilling through wood. Using the incorrect bit will damage the bit and perhaps not accomplish the task. Using a wood bit on metal often does not penetrate the metal.
When you have marked on the material to be drilled where you want the hole mark it with a pencil or marker with a dot or ‘x’. Place the drill bit exactly on the mark, squeeze the drill trigger and give just the slightest push to the drill. Let the drill do the work. Be patient and don’t force the drill bit through the hole. Try to keep the drill as perpendicular to the material as possible.
There will be occasions when you have to drill a hole at an angle. In these cases drill carefully. You can draw a pencil line on the material noting the angle and then try to follow that pencil guide as you drill. There are also angle guides you can use. Place these over the spot you want drilled with the guide calibrated at the correct angle. Insert the drill bit into the guide and drill away.
If you are drilling completely through the material when the drill bit begins to exit out the other side of the material be careful; especially with wood. The drill bit exiting the wood can splinter the wood around the exit point. If this part will be hidden, who cares? If it will show, you might want to sand it smooth. Better yet prevent the splintering by covering the exit point with masking or duct tape. The tape will decrease if not prevent the splintering.
Not all holes need to go all the way through the material. Some holes need only be a certain depth in the wood. The easiest way to make certain you drill the co
rrect depth is to measure the needed hole depth on your drill bit. Then mark that point on the bit with a marker or wrap some tape around the bit at the measured spot. Then when you drill only insert the drill bit to the mark or tape. You can also purchase bit collars that slide over the bit and are secured at the appropriate depth. The collars usually attach with a small hex wrench or screwdriver.
The drilling is done and you have to get the bit out. Give the drill a little power to spin the bit and slowly pull it out of the hole. Don’t be too quick or pull it out without spinning the bit. Either of these may cause the bit to bind in the hole.
Get expert Drill Bit advice
The correct drill bit for your needs will give you reliable service - if in doubt as to the type of bits you should buy, contact our friendly team for expert, obligation-free advice!
|
