US Patent: 1,142,138 
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| Combined Lock and Butt Gage
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	        Patentee:
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 | Mathew F. Biersdorf (exact or similar names) - Los Angeles, CA |  
 
 
| USPTO Classifications: |  
| 33/44 |  
 
 
 
 
 
 
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        Patent Dates:
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| Applied: | 
Nov. 16, 1914 | 
 
| Granted: | 
Jun. 08, 1915 | 
 
 
 
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                        Ralph Brendler 
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        Description: |  
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	 This is the first of two patents issued to Mathew Biersdorf
	 for a butt gage suitable for marking both hinge and lock 
	 mortises.  His 1918 patent (1,282,670) was a simplification 
	 of this design, and was produced commercially, but the 
	 production tools were marked with this patent date as well.
	 The main new feature of this tool is the split marking arm,
	 which allows the tool to mark either one line (for hinges) or
	 two lines (for the lock mortise), each accounting for the 
	 gain needed for door layout.
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