Drilling Speeds RPM - Guide
Cutting Speed (m/min) | |||||||||
---|---|---|---|---|---|---|---|---|---|
12 | 18 | 24 | 27 | 30 | 43 | 61 | 91 | ||
Drill Ø (mm) | Stainless Steel | Tool Steel | Cast Iron | Malleable Iron | Medium Carbon Steel | Free Cutting Steel | Aluminium, Brass & Plastic | Wood | Feed per Revolution (mm/rev) |
1 | 2,445 | 3,667 | 4,889 | 5,500 | 6,112 | 8,556 | 12,223 | 18,335 | .05 to .15 |
2 | 1,620 | 2,445 | 3,259 | 3,667 | 4,074 | 5,704 | 8,149 | 12,223 | .05 to .15 |
3 | 1,222 | 1,833 | 2,445 | 2,750 | 3,056 | 4,278 | 6,112 | 9,167 | .05 to .15 |
4 | 978 | 1,467 | 1,956 | 2,200 | 2,445 | 3,422 | 4,889 | 7,334 | .05 to .15 |
5 | 815 | 1,222 | 1.63 | 1,833 | 2,037 | 2,852 | 4,074 | 6,112 | .05 to .15 |
6 | 654 | 982 | 1,309 | 1,473 | 1,637 | 2,292 | 3,274 | 4,911 | .15 to .25 |
7 | 543 | 815 | 1,086 | 1,222 | 1,358 | 1,901 | 2,716 | 4,074 | .15 to .25 |
8 | 489 | 733 | 978 | 1,100 | 1,222 | 1,711 | 2,445 | 3,667 | .15 to .25 |
9 | 448 | 672 | 896 | 1,008 | 1,120 | 1,568 | 2,241 | 3,361 | .15 to .25 |
10 | 407 | 611 | 815 | 917 | 1,019 | 1,426 | 2,037 | 3,056 | .15 to .25 |
11 | 349 | 524 | 698 | 786 | 873 | 1,222 | 1,746 | 2,619 | .25 to .35 |
13 | 306 | 458 | 611 | 688 | 764 | 1,070 | 1,528 | 2,292 | .25 to .35 |
14 | 272 | 407 | 543 | 611 | 679 | 951 | 1,358 | 2,037 | .25 to .35 |
16 | 244 | 367 | 489 | 550 | 611 | 856 | 1,222 | 1,833 | .25 to .35 |
18 | 222 | 333 | 444 | 500 | 556 | 778 | 1,111 | 1,667 | .25 to .35 |
19 | 204 | 306 | 407 | 458 | 509 | 713 | 1,019 | 1,528 | .35 to .45 |
20 | 189 | 224 | 378 | 425 | 473 | 662 | 946 | 1,419 | .35 to .45 |
22 | 175 | 262 | 349 | 393 | 437 | 611 | 873 | 1,310 | .35 to .45 |
25 | 153 | 229 | 306 | 344 | 382 | 535 | 764 | 1,146 | .35 to .45 |
28 | 136 | 204 | 272 | 306 | 340 | 475 | 679 | 1,019 | .35 to .45 |
32 | 122 | 183 | 244 | 275 | 306 | 428 | 611 | 917 | .45 to .55 |
35 | 111 | 167 | 222 | 250 | 278 | 389 | 556 | 833 | .45 to .55 |
38 | 102 | 153 | 204 | 229 | 255 | 357 | 509 | 764 | .45 to .55 |
41 | 94 | 141 | 188 | 212 | 235 | 329 | 470 | 705 | .45 to .55 |
44 | 87 | 131 | 175 | 196 | 218 | 306 | 437 | 655 | .45 to .55 |
47 | 81 | 122 | 163 | 183 | 204 | 285 | 407 | 611 | .55 to .65 |
50 | 76 | 115 | 153 | 172 | 191 | 267 | 382 | 573 | .55 to .65 |
57 | 68 | 102 | 136 | 153 | 170 | 238 | 340 | 509 | .55 to .65 |
63 | 61 | 92 | 122 | 138 | 153 | 214 | 306 | 458 | .55 to .65 |
70 | 56 | 83 | 111 | 125 | 139 | 194 | 278 | 417 | .55 to .65 |
76 | 51 | 76 | 102 | 115 | 127 | 178 | 255 | 382 | .55 to .65 |
Drilling Practice
The flute form, web thickness and split point of the standard Alpha drills are suitable for most materials producing fine chips. For effective drilling,
the rigidity of the drill and work piece are most important. The shorter the flute length, the more rigid the drill. Long drills must be adequately
supported to reduce vibration.
The following are important in drill use:
• Clamp the work-piece securely
• Select the correct speed & feed
• Use an appropriate cutting fluid or lubrication
• Ensure the shank is securely held. Avoid using worn sockets or drill chucks as the drill may slip during use
• Regrind the point or replace the drill before it dulls, do not force a worn drill
• When deep hole drilling, withdraw frequently to clear the chips, deep holes start at 4 times diameter
• When drilling stainless steel, manganese & high tensile steels, it is recommended to use an automatic feed throughout the drilling cycle
• Do not allow the drill to dwell as it will cause work-hardening; use a slower speed & heavier feed on these materials