| US Patent: 159,652 
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| Improvement in Tempering Steel Plates | 
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| Patentees: |  
 | Henry Disston (exact or similar names) - Philadelphia, PA |  | Charles T. Shoemaker (exact or similar names) - Philadelphia, PA |  
 
 
 
 
| Manufacturer: |  | Not known to have been produced |  
 
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| Patent Dates: |  
| Granted: | Feb. 09, 1875 |  USPTO (New site tip)
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                        Russ Allen.
 
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| Description: |  | Patent to rapidly harden or temper saw blades and other steel objects buy having them traverse down an inclined furnace flue. |  |