General/Special Purpose Taps Spiral Flute					Spiral Flute
						Bright				Surface Treated
PREFERRED		ACCEPTABLE				PT148P,B PT140P,B		PT149P,B PT141P,B PT141MP,MB		PT147BS PT142BS
In the chart detailed below, recommended cutting speed is given in Surface Feet Per Minute (S.F.M.). Refer to tapping feed chart for Revolutions Per Minute (RPM).
Normal Chip Form Code  Extra Short  Short  Middle/Short  Middle  Middle/Long  Long  Extra Long 1 2 3 4 5 6 7		Note: Optimum cutting speeds for taps are influenced by the usual factors which include machinability and chip formation characteristics of the material being tapped, workpiece geometry and tap design. Thread pitch, although often overlooked, is a significant factor in choosing the correct cutting speed for a given application. In some instances, tabulated tap cutting speeds will have to be adjusted to accommodate the influence of thread pitch.
						25		26, 27		28
Main  Group	Sub-Group	Examples	Brinell Hardness HB	Normal Chip Form
1. Steel
S.1	Magnetic Soft Steel, Leaded Steels	Leaded Steels	120	7		60		--		70
S.2	Structural Steel, Case Carburizing Steel	ASTM A36 35, 30	200	5		50		--		60
S.3	Plain Carbon Steel	1008, 1024, 1060, 1061	250	6		35		--		40
S.4	Alloy Steel	1345, 4140, 4340, 8620	250	6		35		--		40
S.5	Alloyed Steel Quenched and Tempered Steel	1330, 4130, 5160 A2, 4140, 8630, M2	> 250 350	6		--		--		30
S.6	Alloy Steel Hardened and Tempered Steel	4150, 8650, 52100	> 350 425	6		--		--		--
S.7	Tool Steels	A2, D2, H13, 01	250	5		30		--		35
2. Stainless Steel
SS.1	Free Machining Stainless Steel	303, 416, 430F	250	4		25		--		30
SS.2	Austenitic	304, 316, 321	250	6		20		--		25
SS.3	Ferritic + Austenitic, Ferritic, Martensitic	416Se, 449F, 446	300	6		20 --		-- --		20 --
3. Cast Iron
CL.1	Gray Iron Ferritic	ASTM A48 class 20, 25	150	1		--		--		--
CL.2	Gray Iron Pearlitic or Acicular	ASTM A48 Class 40, 55, 60	> 150 300	1		--		--		--
CL.3	Malleable Cast Iron Nodular Graphite	ASTM A220 Grade 40010 ASTM A602 Grade M8501	> 160 240	3		--		--		--
CL.4	Malleable Cast Iron Nodular Graphite	ASTM A220 Grade 90001 ASTM A602 Grade M8501	> 240 320	3		--		--		--
4. Titanium
T.1	Titanium, Unalloyed	Commercially Pure 99.0	200	7		20		--		20
T.2	Titanium, Alloys Cast	ASTM B367 Grades C-1, C-7A	270	5		15		--		15
T.3	Titanium, Alloys	Ti6A14V, Ti6A16V25n	> 270 350	5		5		--		5
5. Nickel
N.1	Nickel, Unalloyed	Nickel 200, Nickel 230	170	7		20		--		--
N.2	Nickel, Alloys	Nimonic 75, Monel 400 Hastelloy C, Inconel 600	270	6		15		--		--
N.3	Nickel, Alloys	Nimonic 80 Inconel 718 Inconel 825	>270 400	6		--		--		20
6. Copper
C.1	Wrought Copper Alloys	101, 130, 170, 630, 725	100	7		--		30		--
C.2	Brass, Bronze	ASTM B30	200	3		--		80		--
C.3	Brass	ASTM B36	200	6		--		60		--
C.4	High Strength Bronze	Phosphor Bronze	470	2		--		--		--
7. Aluminum Magnesium
A.1	Al, Mg, Unalloyed	EC, 1060, 1100	100	7		--		50		--
A.2	Al, Alloys, Si>5%	6061, 7075, 2024	150	4		--		60		--
A.3	Al, Alloys, Si>5% 10%	356, 380	120	3		--		60		--
A.4	Al Alloyed, Si>10%, Whiskers Reinforced Al-Alloys, Mg Alloys	4032, 390, 392.0	120	2		--		--		--
8. Synthetic
Sy.1	Thermoplastics	Polystyrene, Nylon PVC		7		--		30		--
Sy.2	Thermosetting plastics	Bakelite		2		--		--		--
Sy.3	Reinforced Plastic Materials	Kevlar		1		--		--		--