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IV. — An Instrument for Micro-ruling on Glass and Steel. 

 By J. F. Stanistreet. 



Plate CVI. 



[Although an illustration in the form of a woodcut of this ingenious little 

 machine has appeared elsewhere, we have thought it worth while for the benefit of 

 our readers to reproduce a plate of the apparatus on a larger scale and in clearer type. 

 The adjacent Plate is copied from a photograph of the machine. — Ed. ' M. M. J.'] 



To the ' English Mechanic ' Mr. Stanistreet sent the following 

 description, as it was in its pages that he first saw a reprint of Mr. 

 Slack's paper, which appeared in this Journal some months ago, 

 " On Optical Appearances of Cut Lines in Glass." Mr. Stanistreet 



It may encourage your more ahle readers to know that my 

 lathe and tools, as well as my experience in using them, have been 

 all self-acquired within the last two or three years, during my 

 confinement to the house as a permanent invalid, and that I never 



EXPLANATION OF PLATE CVI. 



Fig. 1. — Diamond, set at an angle of 60°. 



„ 2. — Mandril, to which the disk to be ruled is cemented. 



„ 3. — Worm-wheel of 2.50 teeth worked by endless screw — the wheel is gradu- 

 ated with index, and has spring stops for one-half or one-fourth of a 

 revolution, thus dividing the periphery of the circle into 1000 parts, 

 or to 0° 21' 36". 



„ 4. — Leading screw of 100 threads per inch. 



„ 5. — Winch turning the leading screw, with spring stops for subdividing to 

 the 1 o o\) o o ^^ of an inch, if a diamond fine enough for such a scale 

 should ever be obtained. 



„ 6. — Spring made from pianoforte wire. 



„ 7. — Pressure spring working on glass roller. 



„ 8, 9, 10. — Springs for delicate adjustment of pressure — one above, one below, 

 and one lateral. 



„ 11. — Graduated arc of circle from 0° to 90°, giving divisions from the yJ^,^th 

 to the Towfjt^ of ^"^ mch. ajjart, in the ratio of the cosine of the angle 

 at which the ruling bar is set. When jjlaced at 0^ it rules lines the 

 •j-oVo^^ of an inch apart. The machine when photographed wns set at 

 an angle of 60° for ruling 2000 lines per inch (the cosine of 60° being 

 0'5, or one-half of the radius). To rule 10,000 lines per inch it is 

 placed at an angle of 84° 15' 39" (the cosine of which is 0*10, or one- 

 tenth of the radius). 



„ 12. — Double-handled winch for winding up the self-acting machinery. This 

 consists of a train of wheels and pinions driven by the spring of a mu- 

 sical box, and ending in a fly, wliich regulates and controls the rota- 

 tion of the cam plate. The fly makes 3840 revolutions for eacli turn 

 of the spring wheel ; and the machine will rule more than 1000 lines 

 without being re-wound. Since the photograph was done an addition 

 has been made of a wheel and index for recording the number of lines 

 actually ruled. 



„ 13. — Fly, regulating the rotation of the cam plate. 



„ 14. — Trigger and springs for starting the machine. 



[Note. — Tiie spirit lamp, match box, and oil bottle, &c., ought to have been 

 removed ; but being let into the stand of the machine they have been copied by 

 the photographer.] 



