MARTIN ENGINEERING INFORMATION
14-1/2¼ Spur Gear Horsepower Ratings
3 D.P. — 3" Face
No. Teeth 50 RPM 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 6.14  11.37  19.8  26.3  39.14  46.74   51.78      
15 8.76 15.96 27.06 35.24 50.49 59.01      
18 11.37 20.38 33.75 43.20 60.00   68.93      
21 13.92 24.59 39.84 50.24   67.96        
24 16.32 9.67 28.53 16.84 45.16 26.76 56.19 33.30 74.34 44.05            
48 32.28 19.50 51.30 30.98 72.69 43.90 84.44 51.39          
72 45.01 27.06 66.98 40.29 88.62 53.32            
96 54.74 32.95 77.57 46.70 98.01 59.01            
120 62.89 37.74 85.79 51.48 104.88 62.93                    
4 D.P. — 2" Face
No. Teeth 50 RPM 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 2.35  4.42  7.92  10.77 10.77 16.8  20.65  23.33   27  
16 3.81 6.85 11.92 15.82 15.82 23.60 28.18   31.23    
20 5.06 9.22 15.65 20.38 20.38 29.19 31.11      
24 6.27 3.77 11.25 6.75 18.64 11.19 23.86 23.86 33.14 19.88 38.17 22.84      
36 10.03 5.96 17.23 10.24 28.01 15.98 33.05 33.05 42.89 25.49        
48 12.94 7.82 21.44 12.95 31.91 19.28 38.12 38.12 47.31 28.58            
72   11.10   17.32   24.05            
96   13.78   20.50   27.12            
144   18.00   25.00   31.00                    
5 D.P. — 13Ú4" Face
No. Teeth 50 RPM 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 1.32  2.54  4.63  6.4  10.33  12.98  14.9   17.48  
18 2.50 4.66 8.22 11.00   16.67 20.13   22.45    
24 3.64 2.16 6.55 3.95 11.18 6.73 14.62 8.79 21.09 12.69 24.74 14.88      
30 4.68 2.79 8.45 5.02 14.00 8.31 17.92 10.65 24.88 14.79 28.58 17.00      
45 7.59 4.32 12.20 7.43 19.03 11.59 23.41 14.27 30.38 18.52        
60   5.62   9.31   13.86   16.56   20.55            
80 11.96 7.25 19.00 11.54 26.92 16.35 31.28 18.99          
100   8.51   13.07   17.84            
120 16.23 9.74 24.16 14.49 31.95 19.18            
160   11.77   16.68   21.09                    
6 D.P. — 1/2" Face
No. Teeth 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 1.54  2.83  3.97  6.57  8.4   9.78   11.69  
18 2.83 5.09 6.91   10.80 13.28 14.98   17.22  
24 4.02 7.02 9.32   13.86 16.56   18.35    
30 5.16 8.75 11.41   16.35   19.10      
36 6.26 3.77 10.37 6.24 13.28 7.98 18.44 11.09        
48 7.56 4.88 12.91 7.75 15.98 9.64 20.66 12.75            
84 12.86 7.60 17.62 11.02 20.51 12.96          
120 15.99 9.50 20.86 12.95            
180   12.00   15.00                    
8 D.P. — 11/4" Face
No. Teeth 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 0.72  1.37  1.95  3.32  4.36  5.21  6.38 
18 1.37 2.52 3.49 5.69 7.20 8.30   9.80  
24 1.98 1.18 3.59 2.13 4.81 2.86 7.55 4.48 9.25 5.49 10.48 6.22 12.08 7.17
36 3.02 5.13 6.73   9.85        
48 4.08 2.50 6.76 4.14 8.58 5.26 11.91 7.29        
60   2.98   4.79   5.98                
72   3.47   5.45   6.67          
96   4.40   6.49   7.75          
112   4.83   7.01            
120   5.05   7.22                    
160   6.02   8.21                    
10 D.P. — 1" Face
No. Teeth 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 0.38  0.75  1.08  1.88  2.50  3.00  3.75 
18 0.72 1.33 1.87 3.15 4.07 4.76   5.75  
24 1.08 1.98 2.71 4.33 5.41 7.21   7.21  
28 1.24 0.80 2.24 1.44 3.06 1.94 4.83 3.03 5.98 3.71 6.79 4.85 7.85  
48 2.26 1.31 3.77 2.23 4.94 2.91 7.13 4.20 8.23 4.92      
60 2.68 1.61 4.45 2.66 5.65 3.41 7.84 4.73 9.04 5.43        
72   1.88   3.02   3.80   5.16        
96   2.37   3.65   4.46   5.73        
120   2.80   4.17   4.98   6.18        
140   3.12   4.52   5.33          
180   3.63   5.04   5.81                
200   3.88   5.29   6.02                
12 D.P. — 3Ú4" Face
No. Teeth 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 0.21  0.39  0.55  0.99  1.33  1.64  2.09 
18 0.38 0.71 1.01 1.73 2.28 2.70   3.32  
24 0.56 1.05 1.43 2.37 3.01 3.50   4.17  
36 0.88 0.53 1.57 0.95 2.13 1.28 3.33 2.01 4.09 2.46 4.62 2.46 5.31 3.21
48 1.16 0.70 2.02 1.22 2.70 1.62 3.99 2.41 4.76 2.88 4.76 3.19  
60 1.46 0.87 2.44 1.47 3.19 1.91 4.61 2.74 5.32 3.21        
72 1.71 1.04 2.84 1.72 3.60 2.18 5.00 3.03 5.76 3.49      
96   1.30   2.06   2.56   3.39        
120   1.54   2.37   2.90   3.68        
200   2.19   3.08   3.56                
16 D.P. — 1Ú2" Face
No. Teeth 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 0.08  0.14  0.21  0.40  0.53  0.66  0.87 
18 0.14 0.27 0.39 0.70 0.94 1.14   1.44  
24 0.21 0.39 0.56 0.96 1.26 1.50   1.84  
36 0.32 0.14 0.60 0.27 0.82 0.37 1.35 0.60 1.71 0.68 1.97 0.87 2.33 1.03
48 0.45 0.82 1.10 1.72 2.11 2.39   2.75  
60   0.34   0.60   0.80   1.20   1.44   1.60    
72   0.40   0.69   0.91   1.33   1.57      
80 0.76 0.45 1.26 0.75 1.65 0.99 2.38 1.43 2.75 1.64      
120   0.63   1.00   1.25   1.68        
160   0.78   1.21   1.48   1.78            
200   0.93   1.34   1.60   1.78            
20 D.P. — 3/8" Face
No. Teeth 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM
Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 0.05  0.07  0.10  0.19  0.27  0.33  0.46 
18 0.07 0.13 0.19 0.35 0.48 0.59   0.76  
24 0.11 0.20 0.29 0.51 0.68 0.81   1.02  
48 0.22 0.14 0.43 0.26 0.58 0.35 0.93 0.56 1.16 0.70 1.34 0.81 1.55 0.94
60 0.28 0.50 0.67 1.06 1.29 1.47   1.69  
80   0.22   0.39   0.52   0.76   0.91   1.01    
96 0.46 0.26 0.76 0.99 1.44   1.66 1.70    
120   0.32   0.53   0.66   0.92   1.06      
160   0.40   0.64   0.79   1.05   1.16      
200   0.47   0.73   0.89   1.08   1.14        
24 D.P. — 1/4" Face
No. Teeth 100 RPM   200 RPM   300 RPM   600 RPM   900 RPM   1200 RPM  
  Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron Steel Cast Iron
12 0.017  0.033 0.049 0.092 0.131 0.165  
18 0.030 0.060 0.090 0.170 0.230 0.290  
24 0.047 0.091 0.132 0.236 0.321 0.391  
36 0.080 0.150 0.210 0.360 0.470 0.550  
48 0.105 0.197 0.275 0.455 0.583 0.679  
60 0.130   0.240   0.330   0.530   0.670   0.760  
96 0.210 0.360 0.480 0.710 0.850   0.940  
144 0.291   0.482   0.617   0.857   0.984      
Note: 1. Pitch line velocities exceeding 1000 feet per minute are not recommended. They should be used for interpolation purposes only.

2. Non-metallic gears are most commonly used for the driving pinion of a pair of gears, with mating gear made of Cast Iron or Steel, where pitch line velocities exceed 1000 FPM and are not subjected to shock loads.
close window