New Engine for Ruling. 93'- 



PI. XIV. — Fig. 1. Curve showing result of corrections. 



Fig. 2. Plan of apparatus for testing the screw. 

 „ XV. — General view of apparatus for cutting ratchet teeth. 

 ,, XVI. — Fig. 1. Thrust block and sapphire thrust plate, slightly 

 enlarged. 

 Fig. 2. Diamond carriage — back view. 

 Fig. 3. Diamond carriage — front view. 

 ,, XVII. — Microphotographs. 



Fig. 1. Commencement of lines ruled with a correctly 



adjusted diamond, x 66. 

 Fig. 2. Termination of lines ruled with a correctly 



adjusted diamond, x 66. 

 Fig. 3. Lines ruled with an incorrectly adjusted 



diamond, x 50. 

 Fig. 4. Lines ruled with an incorrectly adjusted' 



diamond, x 50. 

 Fig. 5. Fine lines ruled with a correctly adjusted 



diamond, 9000 to the inch, x 300. 

 Fig. 6. Fine lines ruled with a correctly adjusted 

 diamond, 55,000 (Right) and 60,000 (Left) to 

 the inch, x 1300. 



Key to mimhers on Plate VI. — the Plan of the Machine. 



A. Main cast iron Bed of Machine. 



B. Base plate supporting ratchet mechanism. 



C. Base plate supporting mechanism controlling ruling carriage.. 



D. Base plate supporting main driving shaft. 



1 Precision screw; 20 threads per inch. 



2 Steel casing of nut. 



3 Ring of steel surrounding nut with pressure and trans- 



mission-rod adjustment. 



4 Nut extension bar. 



5 Bearing support for guiding 4. 



6 Lock nut to prevent end play of screw when reversed. 



7 Inserted hardened steel thrust. 



8 Main bearings supporting screw with caps and bolts. 



9 Ratchet wheel. 



10 Shoulder plate and hub to which 9 is bolted. 



11 Base plate supporting arrest pillar of ratchet wheel. 



12 Lock nut for fixing handle to screw (when required). 



