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Suggested Cutting Speeds With HSS Tools
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MATERIAL |
BRINELL |
DRILLS
S.F.M. |
TAPS - S.F.M.
THREADS PER INCH |
|
3-8 |
9-15 |
16-24 |
25 UP |
|
Aluminum (die cast) |
95-105 |
250 |
50 |
100 |
130 |
150 |
|
Aluminum |
95-105 |
200 |
50 |
100 |
130 |
150 |
|
Bakelite |
--- |
80 |
50 |
100 |
130 |
150 |
|
Brass |
192-202 |
200 |
50 |
100 |
130 |
150 |
|
Bronze Common |
166-183 |
200 |
40 |
80 |
100 |
150 |
|
Bronze Phos. 1/2 hard |
187-202 |
175 |
25 |
40 |
50 |
80 |
|
Copper |
80-85 |
70 |
40 |
80 |
100 |
150 |
|
Cast Iron - soft |
126 |
140 |
30 |
60 |
90 |
130 |
|
Cast Iron - hard |
300 |
45 |
10 |
20 |
30 |
40 |
|
Cast Iron, Malleable |
112-126 |
85 |
20 |
30 |
40 |
50 |
|
Duralumin |
90-104 |
200 |
50 |
100 |
130 |
150 |
|
Nickel |
187-202 |
75 |
25 |
40 |
50 |
80 |
|
Rubber - hard |
--- |
100 |
50 |
100 |
150 |
200 |
|
Steel - mild .20-.30C |
170-202 |
115 |
40 |
55 |
70 |
90 |
|
Steel - .40-.50C |
170-196 |
80 |
20 |
30 |
40 |
50 |
|
Steel, Stainless |
460-520 |
20 |
8 |
10 |
15 |
20 |
|
Steel, Tool |
241 |
50 |
15 |
15 |
20 |
20 |
|
Zinc |
110-125 |
200 |
50 |
100 |
130 |
150 |
|
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Feeds For High Speed Drills
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Drill Diameter Inches
|
Feed Inch Per Revolution
|
|
1/16 to 1/8
|
.001 - .003
|
|
1/8 to 1/4
|
.002 - .006
|
|
1/4 to 1/2
|
.004 - .010
|
|
1/2 to 1"
|
.007 - .015
|
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Useful Formulas
RPM = 3.82 x SFM
Dia.
SFM = .262 x D x RPM
1 ÷ Pitch = Tap Lead
% of Threads (cut taps) =
threads per inch x (major dia. of tap - drill dia.)
.01299
Example for 1/4-20 tap, using # 7 drill.
.250 - .201 = .049 ÷ .01299 = 3.77 x 20 = 75% thread
Note: Use .0068 divisor for roll form taps.
Tap Drill Size (cut taps)
= major Dia of tap - (.01299 x % of full thread)
TPI
Example for 1/4-28 with 70% required threads.
.01299 x 70 = .909 ÷ 28 = .032
.250 - .032 = .218 drill size
Tap Drill Size (form taps)
= major Dia tap - (.0068 x % full thread)
TPI
Example for 1/4-20 tap with 65% required threads.
.0068 x 65 = .442 ÷ 20 = .022
.250 - .022 = .228 drill size
Calculation of tapping cycle time for Procunier
tappers.
Inch cycle time (seconds) = (90 x TPI x travel)
RPM
MM cycle time (seconds) = (2286 x travel)
MM (pitch) x RPM
Example for 10-32 at 1140 RPM
90 x 32 x .625 ÷ 1140 = 1.6 seconds
Example for M10 x 1.25 at 860 RPM
2286 x .950 = 2171.7
1.25 x 860 = 1075
2171.7 ÷ 1075 = 2. seconds
Notes:
Formulas include 2:1 reverse found on all Procunier tappers.
Travel includes tap clearance above piece part and total depth into hole
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Contact us for more information
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