366 TOOL STEEL EOR THE UNITED STATES NAVY. 



7. *From the sample bar, 3! inches round, 2 butt mills, 3I inches 

 diameter, will be made and tested on a nickel-steel block, with cut 0.20 inch 

 deep, ij inches wide, feed 0.04 inch per revolution of mill, at a speed of 100 

 feet per minute. Each mill to run at least 40 inches and be in fair condition 

 at end of run. Lubricant to be used. 



8. Class 2. — The bar will be forged into 5 tools, treated and ground to 

 the No. 22 form of Sellers system of tool forms. Bach tool will be tested 

 on a carbon open-hearth steel forging of about 60,000 pounds tensile strength, 

 with a cut ^ inch deep, | inch feed, and a cutting speed of about 50 feet 

 per minute. A record will be made of the length of time the tool cuts with 

 a lubricant or cutting compound before it is ruined. 



9. *From the | by i| inch sample bar, 3 standard round-nose roughing 

 tools will be made and tested on nickel-steel forging, with a j inch cut ; feed 

 0.05 inch per revolution, and a speed of 15 feet per minute. Bach tool 

 should run for 20 minutes without serious injury without a lubricant. 



Carbon Steel. 



10. Class I. — Machinists' taps, |-inch diameter, will be made and 

 tested on nickel steel. A record will be made of the number of holes tapped 

 before the tap is ruined. A lubricant will be used, and the revolutions per 

 minute of the tap will be varied to suit conditions. 



11. *From the 2j-inch square sample bar 3 finishing tools will be made 

 and tested on a nickel-steel forging, with a cut from o.ooi to 0.003 i^ch deep, 

 a feed 2 J inches per revolution, and a speed of 8 feet per minute. Bach tool 

 should make a clean, smooth finish for a run of at least 20 feet without 

 lubrication. 



12. Class 2. — One i-inch end mill will be made and tested with a lubri- 

 cant by cutting a piece of class 4 carbon steel. The depth of cut will be 

 Yi inch, the revolutions per minute will be varied to suit conditions, and a 

 record will be made of the length of time the mill cuts before it is ruined. 



13. *From the sample bar, if inches round, one end mill, if inches 

 diameter, will be made and tested on a mild-steel block, cut 0.20 inch deep, 

 0.50 inch wide; feed 0.018 inch per revolution; at a speed of 40 feet per 

 minute. The mill should run at least 40 inches and be in fair condition at 

 the end of run. Lubricant to be used. 



14. Class 3. — Pneumatic cape chisels, |-inch, will be made and tested 

 with a lubricant on nickel steel. A record will be made of the distance the 

 tool cuts before it is ruined. 



15. Class 4. — Rivet sets, f-inch, will be made and tested, and a record 

 will be made of the number of rivets the set will drive before it is ruined. 



