T-70
If the number of teeth is less than 12, Table 8-5 is used to determine the gear sizes.
Table 8-5 Dimensions for Pinions with Numbers of Teeth Less than 12
NOTE: All values in the table are based on m = 1.
All equations in Table 8-6 (shown on the following page) are also applicable to Gleason
bevel gears with any shaft angle. A spiral bevel gear set requires matching of hands; left-
hand and right-hand as a pair.
8.5.4 Gleason Zerol Spiral Bevel Gears
When the spiral angle bm = 0, the bevel
gear is called a Zerol bevel gear. The calculation
equations of Table 8-2 for Gleason straight bevel
gears are applicable. They also should take
care again of the rule of hands; left and right of
a pair must be matched. Figure 8-12 is a left-
hand Zerol bevel gear.
Fig. 8-12 Left-Hand Zerol Bevel Gear
Number of Teeth in Pinion
z1
Number of Teeth in Gear
z2
Working Depth
hw
Whole Depth
h
Gear Addendum
ha2
Pinion Addendum
ha1
Circular Tooth
Thickness of Gear
Pressure Angle
an
Spiral Angle
bm
Shaft Angle
S
30
40
50
60
6
Over 34
1.500
1.666
0.215
1.285
0.911
0.803
––
––
7
Over 33
1.560
1.733
0.270
1.290
0.957
0.818
0.757
––
8
Over 32
1.610
1.788
0.325
1.285
0.975
0.837
0.777
0.777
9
Over 31
1.650
1.832
0.380
1.270
0.997
0.860
0.828
0.828
10
Over 30
1.680
1.865
0.435
1.245
1.023
0.888
0.884
0.883
11
Over 29
1.695
1.882
0.490
1.205
1.053
0.948
0.946
0.945
20°
35° ... 40°
90°
s2
