|
| |
|
HOW TO
DETERMINE PROPER SPEEDS AND FEEDS FOR THREADS |
| The feed rate is
determined entirely by the lead or pitch of the thread. Since the feed of
the die head must not be too rapid, the thread lead and pitch limit
spindle speed, and therefore the cutting speed. Cutting speed is also
affected by the work material, type and size of thread, thread tolerance,
and the finish required. Cutting fluid should be used in most cases, which
may also have an effect on cutting speed. With thread chasers, much slower
cutting speeds are recommended as compared to turning. Using thread
chasers at a cutting speed that is too fast will reduce tool life and may
cause rough or torn threads on the finished parts. Some typical cutting
speeds and the feed rate formula for thread chasers are given below. These
speeds and feeds are intended to be starting points only and may have to
be modified somewhat to suit your particular job. |
| Use
the following formula for spindle speed. (RPM) |
|
N=12V
*D
|
Where N=Spindle
speed (RPM)
V=Cutting speed (FPM)
D=Diameter (INCHES)
*=3.14
|
|
CUTTING SPEEDS (FPM) FOR THREADS PER
INCH
|
|
MATERIAL
|
3-7
|
8-15
|
16-24
|
25 & UP
|
|
AISI 1010-1035 STEEL
|
20
|
30
|
40
|
50
|
|
AISI 1112-1340 STEEL
|
20
|
30
|
40
|
50
|
|
AISI 1040-1095 STEEL
|
15
|
20
|
25
|
30
|
|
AISI 4130-4820 STEEL
|
8
|
10
|
15
|
20
|
|
AISI 5120-52100 STEEL
|
8
|
10
|
15
|
20
|
|
STAINLESS STEEL
|
8
|
10
|
15
|
20
|
|
GRAY CAST IRON
|
25
|
40
|
50
|
80
|
|
ALUMINUM ALLOYS
|
50
|
100
|
150
|
200
|
|
BRASS BAR STOCK
|
50
|
100
|
150
|
200
|
|
PHOSPHOR BRONZE
|
40
|
80
|
100
|
150
|
|
ZINC DIE CASTINGS
|
50
|
100
|
150
|
200
|
| MATERIAL |
BRINELL |
DRILLS |
REAMERS |
TAPS
- S.F.M. |
| S.F.M |
POINT |
FEED |
S.F.M. |
FEED |
THREADS
PER INCH |
| 3
- 7 1/2 |
8
- 15 |
16-24 |
25-UP |
| Aluminum |
99-101 |
200-250 |
118º |
M |
150-160 |
M |
50 |
100 |
150 |
200 |
| Aluminum
bronze |
170-187 |
60 |
118º |
M |
40-45 |
M |
12 |
25 |
45 |
60 |
| Bakelite |
--- |
80 |
60-90º |
M |
50-60 |
M |
50 |
100 |
150 |
200 |
| Brass |
192-202 |
200-250 |
118º |
H |
150-160 |
H |
50 |
100 |
150 |
200 |
| Bronze,
common |
166-183 |
200-250 |
118º |
H |
150-160 |
H |
40 |
80 |
100 |
150 |
| Bronze,
phosphor, 1/2 hard |
187-202 |
175-180 |
118º |
M |
130-140 |
M |
25 |
40 |
50 |
80 |
| Bronze,
phosphor, soft |
149-163 |
200-250 |
118º |
H |
150-160 |
H |
40 |
80 |
100 |
150 |
| Cast
iron, soft |
126 |
140-150 |
90º |
H |
100-110 |
H |
30 |
60 |
90 |
140 |
| Cast
iron, medium soft |
196 |
80-110 |
118º |
M |
50-65 |
M |
25 |
40 |
50 |
80 |
| Cast
iron, hard |
293-302 |
45-50 |
118º |
L |
67-75 |
L |
10 |
20 |
30 |
40 |
| Cast
iron, chilled* |
402 |
15 |
150º |
L |
8-10 |
L |
5 |
5 |
10 |
10 |
| Cast
steel |
286-302 |
40-50* |
118º |
L |
70-75 |
L |
20 |
30 |
40 |
50 |
| Celluloid |
--- |
100 |
90º |
M |
75-80 |
M |
50 |
100 |
150 |
200 |
| Copper |
80-85 |
70 |
100º |
L |
45-55 |
L |
40 |
80 |
100 |
150 |
| Drop
forging (steel) |
170-196 |
60 |
118º |
M |
40-45 |
M |
12 |
25 |
45 |
60 |
| Duralumin |
90-104 |
200 |
118º |
M |
150-160 |
M |
50 |
100 |
150 |
200 |
| Everdur |
179-207 |
60 |
118º |
L |
40-45 |
L |
20 |
30 |
40 |
50 |
| Machinery
steel |
170-196 |
110 |
118º |
H |
67-75 |
H |
35 |
50 |
60 |
85 |
| Magnet
steel, soft |
241-302 |
35-40 |
118º |
M |
20-25 |
M |
20 |
40 |
50 |
75 |
| Magnet
steel, hard* |
321-512 |
15 |
150º |
L |
10 |
L |
5 |
10 |
15 |
25 |
| Manganese
steel, 7-13* |
187-217 |
15 |
150º |
L |
10 |
L |
15 |
20 |
25 |
30 |
| Manganese
copper, 30 Mn.* |
134 |
15 |
150º |
L |
10-12 |
L |
--- |
--- |
--- |
--- |
| Malleable
iron |
112-126 |
85-90 |
118º |
H |
--- |
H |
20 |
30 |
40 |
50 |
| Mild
steel, .20-.30C |
170-202 |
110-120 |
118º |
H |
75-85 |
H |
40 |
55 |
70 |
90 |
| Molybdenum
steel |
196-235 |
55 |
125º |
M |
35-45 |
M |
20 |
30 |
35 |
45 |
| Monel
metal |
149-170 |
50 |
118º |
M |
35-38 |
M |
8 |
10 |
15 |
20 |
| Nickel,
pure* |
187-202 |
75 |
118º |
L |
40 |
L |
25 |
40 |
50 |
80 |
| Nickel
steel, 3-1/2% |
196-241 |
60 |
118º |
L |
40-45 |
L |
8 |
10 |
15 |
20 |
| Rubber,
hard |
--- |
100 |
60-90º |
L |
70-80 |
L |
50 |
100 |
150 |
200 |
| Screw
stock, C.R. |
170-196 |
110 |
118º |
H |
75 |
H |
20 |
30 |
40 |
50 |
| Spring
steel |
402 |
20 |
150º |
L |
12-15 |
L |
10 |
10 |
15 |
15 |
| Stainless
steel |
146-149 |
50 |
118º |
M |
30 |
M |
8 |
10 |
15 |
20 |
| Stainless
steel, C.R.* |
460-477 |
20 |
118º |
L |
15 |
L |
8 |
10 |
15 |
20 |
| Steel,
.40 to .50C |
170-196 |
80 |
118º |
M |
8-10 |
M |
20 |
30 |
40 |
50 |
| Tool,
S.A.E., and Forging steel |
149 |
75 |
118º |
H |
35-40 |
H |
25 |
35 |
45 |
55 |
| Tool,
S.A.E., and Forging steel |
241 |
50 |
125º |
M |
12 |
M |
15 |
15 |
25 |
25 |
| Tool,
S.A.E., and Forging steel* |
402 |
15 |
150º |
L |
10 |
L |
8 |
10 |
15 |
20 |
| Zinc
alloy |
112-126 |
200-250 |
118º |
M |
150-175 |
M |
50 |
100 |
150 |
200 |
| Drill
Feed Per Revolution in Inches |
Reamer
Feed |
REFERENCE
SYMBOL |
DIAMETER
OF DRILL - INCHES |
ALL
DIAMETERS |
| UNDER
1/8 |
1/8
TO 1/4 |
1/4
TO 1/2 |
1/2
TO 1 |
OVER
1"
DIAMETER |
Use
a feed equal to
two or three times that
recommended for drills. |
| L
- Light |
.001 |
.002 |
.003 |
.005 |
.006 |
| M
- Medium |
.0015 |
.003 |
.006 |
.010 |
.012 |
| H
- Heavy |
.0025 |
.005 |
.010 |
.020 |
.025 |
|
American Made Products !