Using Multiple Metal Drill Bits

Many times, handy men have broken one or more perfectly good drill bits trying to cut through metal. Center drill bits, occasionally known as Slocombe drill bits, are used in metalworking to provide a starting hole for a larger-sized drill bit or to make a conical indentation in the end of a workpiece in which to mount a lathe center In either use, the name seems appropriate, as the bit is either establishing the center of a hole or making a conical hole for a lathe center.

SDS was originally invented by Bosch in 1975 and stood for Steck, Dreh, Sitzt,” which roughly translates to stick, turn, seated.” The letters SDS are now internationally accepted as meaning Special Direct System.” There are different types of SDS drill bits depending on the power output of the drill; the the two most common being SDS-Plus and SDS-Max.

The extractor is pressed against the damaged head and rotated counter- clockwise and will tend to jam in the damaged head and then turn the screw counter-clockwise, unscrewing it. For screws that break off deeper in the hole, an extractor set will often include left handed drill bits of the appropriate diameters so that grab holes can be drilled into the screws in a left handed direction, preventing further tightening of the broken piece.

The correct tool to start a traditionally drilled hole (a hole drilled by a high-speed steel (HSS) twist drill bit) is a spotting drill bit (or a spot drill bit, as they are referenced in the U.S.). The included angle of the spotting drill bit should be the same as, or greater than, the conventional drill bit so that the drill bit will then start without undue stress on the bit’s corners, which would cause premature failure of the bit and a loss of hole quality.

It does matter – wood drill bits won’t work on metal (destroying the bit in the process, unless used on thin and soft metals) and metal drill bits will increase splintering and tear-out when used on wood (but this depends also on the wood type and the diameter of the bit, and for smaller diameters there is little difference between wood and metal drills bits).

You can hide your flathead screws with wood plugs if you drill your countersink deep enough to allow for them to be glued in over the screw. The advantage of this type of bit is obviously the convenience of being able to drill a variety of hole sizes without changing bits. A countersink bit — also called a screw pilot bit — is a specialty bit for drilling in wood. Forstner bits are flat bottomed with a point in the center to keep it on target.

High speed steel (HSS) is a form of tool steel ; HSS bits are hard, and much more resistant to heat than high carbon steel. This in turn helps to improve productivity by allowing you to get more done with each drill bit. For instance, if you have a 13mm (½”) chuck, you can get a reduced shank drill bit with a 16mm diameter and a 13mm shank. Just about all countersink manufacturers make replacement bits that are easy to swap in.

The most efficient way to make a countersink is to take it easy, and decrease the drill speed as the stop nears the surface. Referred to more commonly as fast cut wood drill bits, auger drill bits for wood have a special flute design that allows chips to be removed quickly. They can be used to drill through nearly anything, including plastic, wood, ceramic tiles, masonry, and metal.

Brad Point: Designed for creating blind holes in wood and other soft materials for shelf pins, dowels, etc. These bits are designed to drill flat bottom blind holes for European style hinges, etc. 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. These tungsten carbide tipped drill bits are designed for drilling smooth holes in glass and ceramic surfaces, including porcelain (with the exception of toughened glass). This percussive or hammering action pulverizes the masonry in contact with the tip of the bit.

The chuck on a cordless drill is usually either 10 mm (3/8 inch equivalent) or 13 mm (1/2 inch) Lower voltage drills (e.g. 12 volts) tend to be fitted with a 10 mm chuck. But I found that the drill bits-at least the dime store ones I’m using- the grooved # part of the bit was just the slightest bit thicker than the shaft. For drilling stone or concrete you’ll want to use a good quality masonry bit, and a good rotary hammer drill.

Some professional quality masonry drill bits will also feature a hexagonal shank (instead of a cylindrical shank) to stop the bits from slipping in the chuck when the drill is experiencing substantial loads, and also a percussion ground carbide tip. The drill bit is secured to the bit by a small grub screw and it has the option to be adjusted up and down to the desired length. 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. To reduce heat on the bit you’ll want to drill at a slower speed, and pull the bit out of the hole from time to time to clear the debris.

As far as shims go, a metal feeler gauge set would be flexible, noncompressive, and small enough to fit in confined spaces, as well as having your distance measurements etched in the face of each shim. Like many people, you’ll find that sometimes it works best to have a set of basic wood drill bits and several different metal drill bits. There are also two basic types of diamond drill bits relating to the application of the diamonds – bonded and sintered.drill bits for wood and metal	drill bits for wood and metal

For example, glass varies in hardness depending upon color and type, since various metals and minerals are added to achieve the different types and colors. However, solid drill bits are not practical when drilling in extremely hard materials and solid diamond drill bits are rarely made. Used on hammer drills and designed for a variety of masonry surfaces – bricks, concrete, stone. Some bits are difficult (or dangerous) to use with handheld drills and require a drill press.

Also known as a wood or dowel bit, they have a central point and two raised spurs that help keep the bit drilling straight. When I saw this set in a plastic case (perfect for easy retrieval from my crowded tool bag) with so many bits graduated in size (so no matter the size of the screw I would have the right size bit) at such a low price I couldn’t resist trying them.