Chapter XI: =drilling and Boring in the Lathe.=

=The Twist Drill= 274
Twist drill holders 274
The diametral clearance of twist drills 274
The front rake of twist drills 275
The variable clearance on twist drills as usually ground 275
Demonstration of the common error in grinding twist drills 276
The effects of improper grinding upon twist drills 276
Table of speeds and feeds for twist drills 277
Grinding twist drills by hand 279
Twist drills for wood work 279
=Tailstock Chucks= for drilled work 279
=Flat Drills= for lathe work 280
Holders for lathe work 281
=Half-round= bit or pod auger 281
With front rake for wrought iron or steel 281
With adjustable cutter 281
For very true work 281
=Chucking Reamer= 281
The number of teeth for reamers 282
Spacing the teeth of reamers 282
Spiral teeth for reamers 282
Grinding the teeth of reamers 282
Various positions of emery-wheel in grinding reamers 282
Chucking reamers for true work 283
Shell reamers 283
Arbor for shell reamers 283
Rose-bit or rose reamers 283
Shell rose reamers 284
Adjustable reamers 284
Stepped reamers for taper work 285
Half-round reamers 285
Reamers for rifle barrels 285
=Boring Tools= for lathe work 285
Countersinks 285
Shapes of lathe boring tools 285
Boring tools for brass work 286
The spring of boring tools 286
Boring tools for small work 287
Boring tool holders 287
=Boring Devices for Lathes= 288
=Boring Heads= 288
=Boring Bars= 289
Boring bar cutters 289
Three _versus_ four cutters for boring bars 290
Boring bars with fixed heads 290
With sliding heads 290
Bar cutters, the shapes of 291
Boring head with nut feed 291
Boring bars for taper work, various forms of 292
Boring double-coned work 293
Boring bar, centres for 293
=Cutting Speeds= and feeds for wrought iron 294
Examples of speeds taken from practice 295