Description
Straight Shank Flat Counterbores Drill With Guide Pole
1). Material: High Speed Steel/ Carbide/ steel
2). Hardness: Upon requirment
3). Heat Treatment: Easily heat treated
4). Quality: High precision, professional technology and skill
5). More Information about Counterbore:
A. Counterbore
A counterbore can refer to a cylindrical flat-bottomed hole, which enlarges another hole, or the tool used to create that feature. A spot face is a very shallow counterbore. A counterbore hole is used when a fastener is required to sit flush with or below the level of a workpiece's surface.
B. Description
A counterbore hole is usually used when the head of a fastener, such as a hex head or socket head capscrew, is required to be flush with or below the level of a workpiece's surface.
For a spot face, material is removed from a surface to make it flat and smooth, usually for a fastener or a bearing. Spot facing is usually required on workpieces that are forged or cast. A tool referred to as a counterbore is typically used to cut the spot face, although an endmill may also be used. Only enough material is removed to make the surface flat.
A counterbore is also used to create a perpendicular surface for a fastener head on a non-perpendicular surface. If this is not feasible then a self-aligning nut may be required.
By comparison, a countersink makes a conical hole and is used to seat a flathead screw.
C. Machining
Counterbores are made with standard dimensions for a certain size of screw or are produced in sizes that are not related to any particular screw size. In either case, the tip of the counterbore has a reduced diameter section referred to as the pilot, a feature essential to assuring concentricity between the counterbore and the hole being counterbored. Counterbores matched to specific screw sizes generally have integral pilots that fit the clearance hole diameter associated with a particular screw size (e.g., .191 inches for a number 10 machine screw). Counterbores that are not related to a specific screw size are designed to accept a removable pilot, allowing any given counterbore size to be adapted to a variety of hole sizes. The pilot matters little when running the cutter in a milling setup where rigidity is assured and hole center location is already achieved via X-Y positioning.
The uppermost counterbore tools shown in the image are the same device.
The smaller top item is an insert, the middle shows another three-fluted counterbore insert, assembled in the holder. The shank of this holder is a Morse taper, although there are othermachine tapers that are used in the industry. The lower counterbore is designed to fit into adrill chuck, and being smaller, is economical to make as one piece.
6). Application of Counterbore:
Application materials: die steel, cast iron, carbon steel, alloy steel, tool steel and general iron materials
1. Used for Hexagon screw, mold thimble and counterbore processing.
2. Maintain the maximum temperature of cutting is 450°C~550°C
3. Non-stardard size end milling tools can be made as your drawing or samples
size
pilot
cutter
shank
overall
dia
dia
dia
length
M3
3.2
6
5
71
M3
3.4
6
5
71
M3.5
3.7
6.5
5
71
M4
4.3
8
5
71
M4
4.5
8
5
71
M4.5
4.8
8
8
71
M5
5.3
10
8
80
M5
5.5
10
8
80
M6
6.4
11
8
80
M6
6.6
11
8
80
M8
8.4
15
12.5
100
M8
9
15
12.5
100
M10
10.5
18
12.5
100
M10
11
18
12.5
100
M12
13
20
12.5
100
M12
13.5
20
12.5
100
M14
15
24
12.5
100
M14
16
24
12.5
100
M16
17
26
12.5
100
M16
18
26
12.5
100
M18
19
30
12.5
100
M20
21
33
12.5
125
M20
22
33
12.5
125
M24
25.4
40
16
254
Complaint
