Smithy GN1300 - Manual (Page 121)

Appendix B
Inch Feed Rates
Inch threads
are defined as
the number of
threads in
one inch.
Metric threads are
defined as the dis-
tance between two
adjacent crests.
METRICTHREADS INCH THREADS
”
Longitudinal Feed Cross Feed
FEED RATES =
I II III I II III
0.0197” 0.0098” 0.0049” 0.0062” 0.0031” 0.0015”
0.0172” 0.0086” 0.0043” 0.0054” 0.0027” 0.0014”
0.0153” 0.0076” 0.0038” 0.0048” 0.0024” 0.0012”
0.0137” 0.0069” 0.0034” 0.0043” 0.0022” 0.0011”
0.0125” 0.0062” 0.0031” 0.0039” 0.0020” 0.0010”
0.0115” 0.0057” 0.0029” 0.0036” 0.0018” 0.0009”
0.0106” 0.0053” 0.0026” 0.0033” 0.0017” 0.0008”
Distance traveled per
Spindle Revolution
”
I II III I II III
0.70 0.35 3.50 1.75
0.80 0.40 4.00 2.00 1.00
0.45 4.50
1.00 0.50 5.00 2.50 1.25
5.50 2.75
0.60 6.00 3.00 1.50
6.50 3.25
I II III
7 14 28
8 16 32
9 18 36
10 20 40
11 22 44
12 24 48
13 26 52
1
2
3
4
5
6
7
Gear
Selection
X = Teeth per gear A = 30 B = 66 C = 60 D = 60
A = 33 C = 63
B = 80 D = 60
A = 66 C = 63
B = 64 D = 60
Selector
I - III
S
E
L
E
C
T
O
R
1-7
Lever located
inside Pully Box
below gear cluster
I N C H INCH M E T R I C METRIC
THREADING
CHART
B-1 Or Visit www.smithy.com