About Drill Bits

An annular cutter (also called as core drill, core cutter, broach cutter, Trepanning drill, hole saw, or cup-type cutter) is a hollow, multiple cutting edges cutting tool used to make/drill holes in ferrous and non-ferrous metals. An annular cutter cuts only an annular groove at the periphery of the hole and leaves a solid core or slug at the hole center. Annular cutter is a substitute for slower, more expensive and less efficient Twist drills and Hole saws. The function of Annular Cutters is more or less same as a hole saw but differs in geometry and material. Annular cutters are faster, easier and are more accurate than the conventional twist drills or drill bits.

An annular cutter or core drill removes the material from the metal to create cylindrical holes in a circular cross section. An annular cutter, unlike drill bits, cuts only on the periphery of the hole to be made. Annular cutters use almost the same method as concrete core drills, but are for metal drilling. An annular cutter is a multipoint cutting tool and is made from material like high speed steel and tungsten carbide tips.

Annular cutters are available in different sizes generally starting from diameter 12 mm (1/2’’) to 200 mm (7 7/8’’) and larger if required. The length of the annular cutter can be achieved depending upon the thickness of the material to be drilled. In the market the lengths 30 mm, 55 mm, 75 and 110 mm annular cutters are popularly available. These sizes though vary from manufacturer to manufacturer. The annular cutter’s material should be harder than the material to be drilled. Therefore there are various types of material used to manufacture annular cutters, for example different types HSS and TCT material. Annular cutters are also called as core drills because, after drilling hole, the drilled material is ejected from the cutter in the form of a cylindrical blank, this blank is called a core.

The first annular cutter was invented by Mr. Dough Hougen which he patented in 1973. The High Speed Steel annular cutter was invented in 1983 by Michael Beharry and the tungsten carbide tipped annular cutter was invented in 1985 by Mr. Mikiya Toshio and Mr. Shoji Michihiro.

Though people use annular cutters on conventional drilling machines like radial drilling machines or pillar drilling machine, it is not recommended because these machines have very high RPM which creates high tool breakage risk for annular cutters as they are hollow unlike solid twist drills. It is always recommended to use an annular cutter or core drill with a magnetic core drilling machine (also called as magnetic dril, magnetic base drilling machine, etc.) as these machines are slower. A magnetic drilling machine is ideally made for using annular cutters (Source : www.wikipedia.com).

Ø MM
mm Cutting Depth (mm)
18.0 120
19.0 120
20.0 120
21.0 120
22.0 120
23.0 120
24.0 120
25.0 120
26.0 120
27.0 120
28.0 120
29.0 120
30.0 120
31.0 120
32.0 120
33.0 120
34.0 120
35.0 120
36.0 120
37.0 120
38.0 120
39.0 120
40.0 120
41.0 120
42.0 120
43.0 120
44.0 120
45.0 120
46.0 120
47.0 120
48.0 120
49.0 120
50.0 120
51.0 120
52.0 120
53.0 120
54.0 120
55.0 120
56.0 120
57.0 120
58.0 120
59.0 120
60.0 120
65.0 120
70.0 120
75.0 120
80.0 120
85.0 120
90.0 120
95.0 120
100.0 120
Ø MM
mm Cutting Depth (mm)
18.0 150
19.0 150
20.0 150
21.0 150
22.0 150
23.0 150
24.0 150
25.0 150
26.0 150
27.0 150
28.0 150
29.0 150
30.0 150
31.0 150
32.0 150
33.0 150
34.0 150
35.0 150
36.0 150
37.0 150
38.0 150
39.0 150
40.0 150
41.0 150
42.0 150
43.0 150
44.0 150
45.0 150
46.0 150
47.0 150
48.0 150
49.0 150
50.0 150
51.0 150
52.0 150
53.0 150
54.0 150
55.0 150
56.0 150
57.0 150
58.0 150
59.0 150
60.0 150
65.0 150
70.0 150
75.0 150
80.0 150
85.0 150
90.0 150
95.0 150
100.0 150
Ø MM
mm Cutting Depth (mm)
18.0 200
19.0 200
20.0 200
21.0 200
22.0 200
23.0 200
24.0 200
25.0 200
26.0 200
27.0 200
28.0 200
29.0 200
30.0 200
31.0 200
32.0 200
33.0 200
34.0 200
35.0 200
36.0 200
37.0 200
38.0 200
39.0 200
40.0 200
41.0 200
42.0 200
43.0 200
44.0 200
45.0 200
46.0 200
47.0 200
48.0 200
49.0 200
50.0 200
51.0 200
52.0 200
53.0 200
54.0 200
55.0 200
56.0 200
57.0 200
58.0 200
59.0 200
60.0 200
65.0 200
70.0 200
75.0 200
80.0 200
85.0 200
90.0 200
95.0 200
100.0 200