鑽頭種類

 

 

 

 

 

 

 

 

 

Step Drill Bit

 

 

Center and spotting drill bits

   

 

 

 

Garden machinery

 

 

鑽頭是一種旋轉而頭端有切削能力的工具，一般以碳鋼SK或高速鋼SKH2、SKH3等材料，經銑制或滾制再經淬火熱處理後磨製而成，用於金屬或其它材料上之鑽孔加工。它的使用範圍極廣，可運用於鑽床、車床、銑床、手電鑽等工具機上使用。鑽頭依照不同種類可以劃分為以下幾種：

A、依構造分類

1、整體式鑽頭：鑽頂、鑽身、鑽柄由同一材料整體製造而成。

2、端焊式鑽頭：鑽頂部位由碳化物焊接而成。

B、依鑽柄分類

1、直柄鑽頭：鑽頭直徑於Ø 13.0mm以下皆採用直柄。

2、錐柄鑽頭：鑽頭柄為錐度狀，一般其錐度均採用莫氏錐度。

 

 

C、依用途分類

1、中心鑽頭：一般用於鑽孔前打中心點用，前端錐面有60°、75°、90°等。

2、麻花鑽頭：工業製造上使用最廣泛的一種鑽頭。

3、超硬鑽頭：鑽身之前端或全部以超硬合金刀具材料製成，使用於加工材料之鑽孔加工。

4、油孔鑽頭： 鑽身有兩道小孔，切削劑經此小孔到達切刃部份以帶走熱量及切屑，使用此鑽頭一般工作物旋轉而鑽頭靜止。

5、深孔鑽頭：最早用於槍管及石包管之鑽孔加工，又稱為槍管鑽頭。

深孔鑽頭為直槽型，在圓管中切除四分之一強的部份以產生刃口排屑 。

6、鑽頭鉸刀：前端為鑽頭，後端為鉸刀。鑽頭直徑與鉸刀直徑只差鉸孔之裕留量，

也有鑽頭於螺攻絲混合使用，故又稱為混合鑽頭。

7、錐度鑽頭：當加工模具進料口時可使用錐度鑽頭。

8、圓柱孔鑽頭：我們稱其為沉頭銑刀，此種鑽頭前端有直徑較小之部分稱為道杆。

9、圓錐孔鑽頭：為鑽削圓錐孔之用，其前端角度有90°、60°等。

我們使用的倒角刀就是圓錐孔鑽頭的其中一種。

10、三角鑽頭： 一種電鑽所使用之鑽頭，其鑽柄製成三角形之面使夾頭可確實固定鑽頭。

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Forstner bit

 

 

 

Center bit

 

 

Auger bit

 

 

Gimlet bit

 

 

Hinge sinker bit

 

Adjustable wood bit

 

PCB drill bit

 

 

 

 

 

 

 

 

 

 

 

 

 

HSS metal drill bits

HSS stands for high speed steel and these bits are for drilling steel and other non ferrous metals, at high speeds up to 13mm diameter holes. Because they are 'high speed' they can withstand the hot temperatures that are generated when drilling metal though for larger holes or thicker metal lubricating the bit with oil whilst drilling is recommended.

They are also a good all round bit to use on softer materials than steel such as plastic and wood but never use them on masonry. Bricks, plaster, concrete blocks and anything similar will ruin the cutting edge on HSS bits instantly.

The set of Dewalt HSS bits I use aren't cheap but they do have a smaller pilot bit at the front that prevents the bit from wandering when starting a hole and that also speeds up the time it takes to drill a hole in metal. They have a Gold ferrous oxide coating that helps prevent overheating and prolongs the life of them too.

Masonry bits

Masonry bits are for drilling holes in bricks, concrete, concrete blocks, Thermalite, cement, plaster, stone and are also good for drilling ceramic tiles.

Typically they are used in a hammer or percussion drill that 'hammers' at the same time as spinning the drill bit in order to break up the hard materials (don't use the hammer action when drilling tiles!).

Unlike HSS bits, masonry bits need to be used at slower speeds and it's important to move the bit in and out of the hole as you drill so as to clear the dust and debris that builds up.

Masonry bits are available in really long lengths to get through both layers of brickwork in a cavity wall and can be used for holes up to around 25mm in diameter. After which a diamond tipped hole saw called a core drill is more suitable.

Auger & Flat wood bits

  

Both these types of drill bits are used for drilling small to medium holes in wood. Their design makes them perfect for boring long, straight holes, good for jobs like mortice locks and latches. They are really good for quickly removing lots of timber when morticing to take a tenon for example when making staircase components.

Auger bits have a threaded tip at the end that guides and pulls the rest of the bit through the timber. The next part of the bit is a cutting 'ear' that like the name suggests does the cutting and can be sharpened. The rest of the long drill bit is fluted and these flutes help to remove the waste timber. If the bit gets stuck in use, simply wind out to clear the hole and then start again.

Auger bits can tend to try and split timber like here when drilling a mortice lock. In these instances put a clamp on the material you are drilling to help stop the bit spreading the timber.

Flat wood bits can be better for tighter spaces and are more manouverable than an Auger bit. Whilst I use Augers mainly for finish carpentry work, I tend to use flat wood drill bits for drilling things like joists and for framing work - generally rougher jobs. Also if I need a notch when framing I can use a flat wood bit then chisel out the rest.

Both types are available up to sizes around 32mm.

Drill & Countersink bits

You can buy separate countersink bits that do just that, countersink a hole for the screws head to sit flush into. I prefer using combined drill and countersinks though with quick release shanks that save the changeover time when using both a drill bit and a countersink. They're available for loads of different screw sizes or you can bury the screw deeper and then use a plug cutter to cut a matching pellet to fill the hole with.

Flip drivers

Flip driver sets combine a pilot and countersink bit on one end with a screwdriver bit at the other. You can simply 'flip' the bit end for end inside the quick release holder to quickly change from one application to the other. These are handy bits that I use for fixing and finish carpentry work to save carrying two or more drills.

Hole saws

Hole saws are just that, round saws you can spin with your drill to cut round holes in timber and metal. Larger holes that you can't use any other type of drill bit for are relatively easy with a hole saw. Typically when you buy a set you'll have an arbour that takes a pilot bit to keep the saw steady whilst drilling and that will lock various different sizes of hole saw into it.

 

 

 

Tip Styles: Twist drill bits are available with different tip styles to suit various applications as outlined below:

·         Conventional Drill Point: This is the most common tip style as seen on everyday general purpose drills. The tip angle is usually 118 degrees but can vary from 90° to high angle "Plexi Point

" for use in acrylics. Conventional drill point drills are the most economical and are easily re-sharpened. Suitable for wood, non-ferrous metals and mild steel.

·         Split Drill Point: This is an advanced drill point that prevents walking and provides improved penetration with less effort. Available in 118 or 135 degree angles, split point drill bits are better for drilling in curved surfaces or in alloy steels. They are more expensive and more difficult to re-sharpen than standard drill points.

·         V-Point: This is a special high angle tip used on drill bits for automated wood boring machines. V-point drills are used to create thru-holes in sheet stock for dowels or other assembly hardware.

·         Brad Point: Designed for creating blind holes in wood and other soft materials for shelf pins, dowels, etc. Bradpoints are also used for thru-holes in CNC applications where a conventional drill point would penetrate the table below the panel. Bradpoints have spurs on the outer edges to prevent splintering and chipping of the surface material as well as a center spur to prevent walking as the bit penetrates the surface.

·         Fishtail Point: These special drill points form a reverse "V" in the tip and are designed for drilling into a surface at an angle without walking. They are commonly used as center drills in counterbores for furniture assembly where panels must be joined at right angles.

·         Taper Point: These drill bits have a very large taper, extending far up the drill which creates a tapered hole. Primarily used for old style wood screws.

Flute Styles: Most twist drills have flutes to evacuate the chips at an unspecified angle, and are suitable for the majority of applications. Some specialty twist drills may be designated as "High Helix", "Fast Spiral" or "Low Helix", "Slow Spiral" for specific applications requiring higher or lower spindle speeds or feed rates.

Shank Styles: Twist drill bits designed for use in automated machinery have fixed diameter (usually 1/2" or 10mm) shanks, threaded shanks, or specialty shanks designed for certain machines. General purpose twist drills for use in portable drills have shanks the same diameter as the bit size (up to a certain diameter), larger diameter bits incorporate a reduced shank (either 1/4", 3/8" or 1/2") to fit into a standard drill chuck. Some bits have 3 flats on the shank to prevent spinning under high torque loads. Others have 1/4" hex shanks for use in a portable drill with a hex bit holder.

Materials: General purpose twist drills for use in portable drills are available in different grades of high speed steel as well as cobalt steel and solid carbide. Twist drill bits for automated machinery are available in carbon steel, high speed steel, carbide tipped, and solid carbide.

Coatings: General purpose drill bits are available with black oxide, bronze oxide, a combination of black and bronze oxide, and TiN coatings. Twist drills for automated machinery on our site are primarily for use in wood or plastics and are not coated.

Counterbore Drill Bits

General Description: Counterbore drill bits create a flat bottom blind hole with a smaller diameter center hole that penetrates through the material. The purpose of a counterbore is usually to conceal the fastener head (by covering the hole) or provide a recess to prevent the fastener from protruding above the surface of the material being drilled. Counterbores on our site are designed for use in wood or plastics and are not intended for counterboring steel.

Tip Styles: The cutting tip of a counterbore drill consists of one or more flat blades extending from the center drill to the outer edge. Counterbores are available with or without spurs (teeth) at the outer diameter of the bit. Counterbores with spurs on the outer edge prevent chipping and splintering on wood or laminated surfaces.

Flute Styles: Some counterbores do not have flutes (except for the center drill) and simply shave away the material, others are designed similar to a twist drill with no tip angle and a replaceable center drill.

Shank Styles: Counterbores for use in hand-held drills typically clamp on to a standard twist drill and therefore have a straight shank the same diameter as the center drill. Counterbores for use in automated machinery have fixed diameter (usually 1/2" or 10mm) shanks, threaded shanks, or specialty shanks designed for certain machines.

Materials: Counterbores are available in Carbon Steel, High Speed Steel, or Carbide Tipped

Coatings: Counterbores on our site do not contain special coatings.

Countersink Drill Bits

General Description: Countersink drill bits create a tapered surface hole with a smaller center hole that penetrates through the material (some are available without a center drill for countersinking existing holes). The purpose of a countersink is to allow a tapered head fastener to sit flush with the surface of the material. Countersinks on our site are designed for use in wood or plastics and are not intended for counterboring steel.

Tip Styles: The cutting tip of a countersink drill consists of two or more flat blades extending from the center drill to the outer edge. Countersinks are made with angles from 60 to 120 degrees but those on our site are typically 82 or 90 degrees. For wood use many times the manufacturer does not specify the angle.

Flute Styles: Some countersinks do not have flutes (except for the center drill) and simply shave away the material, others are designed similar to a twist drill with a replaceable center drill.

Shank Styles: Countersinks for use in hand-held drills typically clamp on to a standard twist drill and therefore have a straight shank the same diameter as the center drill (some have 1/4" hex shanks for hand use in a bit holding screwdriver). Countersinks for use in automated machinery have fixed diameter (usually 1/2" or 10mm) shanks, threaded shanks, or specialty shanks designed for certain types of machines.

Materials: Countersinks are available in Carbon Steel, High Speed Steel, or Carbide Tipped

Coatings: Countersinks on our site do not contain special coatings.

Flat Bottom Boring Bits

General Description: Flat bottom boring bits are similar to counterbores but do not include a center drill. These bits are designed to drill flat bottom blind holes for European style hinges, etc. Flat bottom boring bits are also used for drilling large diameter thru-holes without the plug that is typical when using a hole saw. These thru-hole bits are used for locks, door knobs, wiring holes, etc. Flat bottom boring bits on our site are designed for use in wood or plastics and are not intended for use in steel.

Common types of Flat Bottom Boring Bits include:

·         Forstner Bits

·         Three Wing Drills

·         Door Hinge Bits

·         Mortising Bits

·         Spade Bits

Tip Styles: The cutting tip of a flat bottom boring drill consists of one or more flat blades extending from the center to the outer edge. Flat bottom boring bits are available with or without spurs (teeth) at the outer diameter of the bit. Bits with spurs on the outer edge prevent chipping and splintering on wood or laminated surfaces. Some flat bottom boring bits also include a center spur to keep the bit from walking during the initial cut - Spade bits are a good example.

Flute Styles: Large flat bottom boring bits do not have flutes, they consist of only the cutting surface and the chips remain in the hole until the bit is removed.

Shank Styles: Most large flat bottom boring bits have a fixed size hexagonal shank. The hex shank prevents the bit from spinning in the chuck under excessive loads.

Materials: Flat bottom boring bits are available in Carbon Steel, High Speed Steel, or Carbide Tipped.

Coatings: Flat bottom boring bits on our site do not contain special coatings.

Specialty Drill Bits

General Description: Specialty drill bits are any bit that doesn't fall into one of the four categories above. These bits include:

·         Plug Cutters - Essentially a hole saw without a center drill, these bits are designed to cut round plugs from lumber or other stock that are used to fill a counterbore after fastening the parts. After gluing the plug into the counterbore, the plug is then cut and sanded flush to conceal the hole. Plug cutter bits are measured by their inside diameter (the size of the plug that will be left) and are not meant to drill completely through the stock. Instead, the stock is drilled to a depth slightly deeper than the hole to be filled and the plug is popped out using a small screwdriver or other tool. Plug cutters are almost always used in a hand held drill.

·         Glass and Tile Drills - Used to drill holes (usually for fasteners) in non-tempered glass, tile, and similar materials. These bits feature carbide tips and straight shanks that can be used in either hand drills or automated machinery.

·         Masonry Drills - Used to drill holes in concrete, brick, etc. using a special "hammer drill" which pounds the drill bit as it rotates. A threaded anchor is usually installed if the hole is to be used to attach objects to the surface. Masonry drills have carbide tips and either standard or high helix flutes depending on the intended use. They are typically coated with black oxide to prevent corrosion and feature shanks that are either the same size as the bit or reduced diameter to fit the portable drill chuck.

·         Augers - Designed to bore somewhat large holes deeply into wood or other similar materials. Auger tips feature a protruding tapered screw that helps to pull the bit into the wood with one or two cutting edges similar to a counterbore and may include outer spurs. The flutes of an auger drill bit are extra large to pull the chips up and out of the hole. Augers are normally used in hand held drills and the shank may be round or hexagonal.

·         Annular Cutters - Used to drill larger thru-holes in metal (7/16" and up), these bits require a special machine. Similar to a hole saw, annular cutter bits cut the outer diameter of the hole and leave a solid center slug. This creates a much more efficient drilling process with burr-free holes in tubing, sheet metal and iron bar stock. Annular cutter bits on our site are made from Cobalt High Speed Steel.