Omni Gear and Machine Corporation - Toll Free: (800) 876-7216 - Fax: (815) 723-9207

  Gear
Verniers

GEAR TOOTH VERNIERS
The gear tooth vernier is made to measure the Chordal thickness of the gear teeth at the pitch line.  Allowance may be made for any error in blank size by adjusting the height vernier.
 
Example:
Height Setting
 
 

Thickness Setting 
 

= Addendum of gear + Correction (C)
= Addendum of gear + .0294/4
= Addendum of gear + .007

= T/ Diametral Pitch
= 1.5694/4 = .392

A = Addendum
C= Correction
B= Corrected Addendum
T= Chordal Thickness

Height setting for internal gear (of low pressure angle) = addendum of gear.  
Height setting for internal slotting cutter……………….= dedendum of gear  
Height setting for rotary spur cutter…………………….= dedendum of gear- correction
Height setting for end milling cutter……………………= dedendum of gear- correction  
Height setting for hob and fly hob……………………...= dedendum of gear + correction  
Height setting for gear shaper cutter……………………= dedendum of gear + correction  
Height setting for rack type generating cutter…………..= dedendum of gear  
Chart for obtaining correct addendum “B”, and chordal thickness “T”.  This chart is based on 1 D.P.; for any other D.P. divide these values by the desired D.P. (for circular pitch multiply by C.P. over π)
# of Teeth T. C.
6 1.5330 0.1022
7 1.5568 0.0873
8 1.5607 0.0769
9 1.5628 0.0684
10 1.5643 0.0616
11 1.5654 0.0559
12 1.5663 0.0514
13 1.5670 0.0474
14 1.5675 0.0440
15 1.5679 0.0411
16 1.5683 0.0385
17 1.5686 0.0362
18 1.5688 0.0342
19 1.5690 0.0324
20 1.5692 0.0308
21 1.5694 0.0294
22 1.5695 0.0281
23 1.5696 0.0268
24 1.5697 0.0257
25 1.5698 0.0247
26 1.5698 0.0237
27 1.5699 0.0228
# of Teeth T. C.
28 1.5700 0.0220
29 1.5700 0.0213
30 1.5701 0.0208
32 1.5702 0.0193
34 1.5702 0.0181
36 1.5703 0.0171
38 1.5704 0.0162
40 1.5704 0.0154
43 1.5702 0.0143
46 1.5705 0.0134
50 1.5706 0.0123
55 1.5706 0.0112
60 1.5707 0.0102
68 1.5707 0.0091
75 1.5707 0.0083
86 1.5707 0.0072
100 1.5707 0.0061
125 1.5707 0.0049
150 1.5708 0.0045
200 1.5708 0.0035
250 1.5708 0.0025
RACK 1.5708 0.0000