Determining the cutting speed and the speed
Version 2.1.1 - 2020-07-27 37Translation of original operating manual
GB
Drilling_VC_GB.fm
5.2.1 Examples to calculatory determine the required speed for your drilling machine
The necessary speed is depending on the diameter of the drill bit, on the material which is
being machined as well as on the cutting material of the drill bit.
Material which needs to be drilled: St37
Cutting material (drill bit): HSS spiral bit
Set point of the cutting speed [
v
c
] according to the table: 40 meters per minute
Diameter [d] of your drill bit: 30 mm = 0,03 m [meters]
Selected infeed [f] according to the table: about 0.35 mm/rev
Speed
Set a speed on your drilling machine which is less than the determined speed.
INFORMATION
In order to facilitate the production of larger drill holes they need to be pre-drilled. This way, you
reduce the cutting forces and improve the guiding of the drill bit.
The pre-drilling diameter is depending on the length of the
chisel edge. The chisel edge does not cut, but it squeezes
the material. The chisel edge is positioned at an angle of
55° to the major cutting edge.
As a general rule of thumb it applies: The pre-drilling
diameter is depending on the length of the chisel edge.
Recommended working steps for a drilling diameter of 30 mm
Example:
1st working step: Pre-drilling with Ø 5 mm.
2nd working step: Pre-drilling with Ø 15 mm.
3rd working step: Drilling with Ø 30 mm.
Drill bit
Ø
in mm
Speed n in rpm
39,0 33 49 65 82 98 122 147 163 204 245 286 327 408 490 653 817
40,0 32 48 64 80 96 119 143 159 199 239 279 318 398 478 637 796
41,0 31 47 62 78 93 117 140 155 194 233 272 311 388 466 621 777
42,0 30 45 61 76 91 114 136 152 190 227 265 303 379 455 607 758
43,0 30 44 59 74 89 111 133 148 185 222 259 296 370 444 593 741
44,0 29 43 58 72 87 109 130 145 181 217 253 290 362 434 579 724
45,0 28 42 57 71 85 106 127 142 177 212 248 283 354 425 566 708
46,0 28 42 55 69 83 104 125 138 173 208 242 277 346 415 554 692
47,0 27 41 54 68 81 102 122 136 169 203 237 271 339 407 542 678
48,0 27 40 53 66 80 100 119 133 166 199 232 265 332 398 531 663
49,0 26 39 52 65 78 97 117 130 162 195 227 260 325 390 520 650
50,0 25 38 51 64 76 96 115 127 159 191 223 255 318 382 510 637
n
c
d
------------
40m
min 3 14 0 03m
---------------------------------------------------
425 rpm===
Chisel edge length 10% of the
drill bit - Ø
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