How to select suitable tapping speed for your tapping machine?
HIGH PERFORMANCE TAPS RECOMMENDATION SPEED AND FEED CHART
Many factors determine tapping speeds. The main ones are:-
1) Tapping Thread pitch
2) Tapping Material being tapped
3) Tapping Hole depth
4) Tapping Hole type: through or blind
5) Tapping Depth of thread
6) Tapping Lubricant quality and flow rate
Tapping speeds can be calculated with:- RPM = Feed speed (SFM) /0.26 x Tap OD
Recommended SFM charts are given below
| General Purpose & Other Tap speed | ||
| Material | Grades | SFM(uncoated) |
| P-STEEL | ||
| High Strength Tool Steel | A2,D2,P20,H11,H13,S2,01 | 15-25 |
| Low Carbon | A36,12L14,12L15,1005,1018,1020,1108-1119,1213-1215,1513-1518,4012,5015,9310 | 20-40 |
| Medium Carbon | 1040-1095, 1140-1151, 1330-1345, 1520-1572,4023-4063,4120-4161,4330-4340, 4620-4640, 8620-8660, 8740-8750, 6150, 51000, 52100 | 20-30 |
| M-Stainless Steel | ||
| Austenitic | 301-304L, 310, 316L, 321, 347 | 10-20 |
| Martensitic | 403, 410, 416, 420, 430, 431, 440 | 10-20 |
| Precipitation Hardening | 12/8, 15/5, 17/4, AM-350/355/363, PH13-8MO,PH14-8/MO | 10-20 |
| K - Cast Irons | ||
| Ductile | A536, J434, 60-40-18 | 15-30 |
| Gray | A48, A436, A319, Class 20, G4000 | 15-30 |
| Malleable | A220, A602, J158 | 30-60 |
| N - Non-Ferrous | ||
| Aluminum Alloys | 2014, 2024, 6061, 7075 | 70-90 |
| Aluminum High Silicon | A380, A390 | 60-80 |
| Brass/Bronze | Aluminum Bronze, Low Silicon Bronze | 60-100 |
| Composites | G-10, Fiberglass, Graphite, Graphite Epoxy, Plastics | 50-70 |
| Copper | 60-80 | |
| Magnesium | 60-80 | |
| S - High Temp Alloys | ||
| Cobalt Base | Stellite, HS-21, Haynes 25/188, X40, L605 | |
| Iron Base | Incoloy 800-802, Multmet N-155, Timkin 16-25-6, Carpenter 22-b3 |
10-25 |
| Nickel Base | Inconel 625/718, Inco 700, 713C, 718, Monel 400- 401, 404, K401, Rene, Rene 41 & 95 Hastelloy, Waspoloy, Udimet 500 & 700 |
10-25 |
| Titanium | Commercially Pure, 6Al-4V, ASTM 1/2/3, 6Al-25N- 4Zr-2Mo-Si, Ti-8Al-1Mo, Ti-8Al-4Mo |
5-15 |
With so many factors affecting tapping speeds, some experimentation may be necessary to find the ideal. One suggestion is to start at the slowest speed and work up.
Tapping speeds should be decreased if:-
1) Tapping Lubricant is poor, or flow is restricted
2) Tapping Bottom lead or Spiral flute taps are used
3) Tapping Thread depth (%) increases.
4) Tapping Thread pitch is coarse
5) Tapping Cutting taper threads (50% normal speed)
6) Tapping Cutting Acme or Trapezoidal threads (40% normal speed)
Tapping speeds can be increased if:-
1) Tapping Thread depth decreases
2) Tapping Thread pitch is fine
3) Tapping Coolant flow and quality are good
4) Tapping Spiral point taps are used