Chapter XXIII: =emery Wheels and Grinding Machinery.=

=Grinding Operations=; Classification of 38
The qualifications of emery wheels 38
Cements used in the manufacture of emery wheels 38
Grades of coarseness and fineness of emery wheels 38
Grades of wheels and the work they are suitable for 39
Speeds of emery wheels 39
Balancing emery wheels 39
=Emery Grinding Machines= 40
The Sellers drill grinding machine 41
The construction of the drill holding chuck 41
Varying the drill position to suit the diameter of the drill,
and thus maintain equal conditions for all diameters of
drills 41
Errors of construction in ordinary drill grinding machines 41
The construction whereby the Sellers machine maintains an equal
degree of clearance from end to end of the cutting edge upon
all sizes of drills 41, 42, 43, 44
The Sellers attachment for thinning the points of large twist
drills 44
The front rake of twist drills 44
Emery grinder for true surfaces 45
For engine guide bars 45
For car axle boxes 45
Emery grinder with traversing emery wheel 46
For rough work 46
For planing machine knives or cutters 46
Emery wheel swing frame for dressing large castings, &c. 46
Emery belt grinding machine 47
Presenting emery wheels to the work, or the work to the wheels 47
Annular emery wheels 48
Recessed emery wheel 48
The wear of emery wheels 48
=Polishing Wheels= 49 to 51
The construction of 49
Lapping the leather on 49
Method of keeping them true 50
Charging with emery 50
The speed of 50
Polishing materials for 50
Brush wheels for polishing 50
Speed of brush wheels 50
Polishing materials for brush wheels for brass work 50
Solid leather wheels 51
Rag polishing wheels 51
Polishing materials for rag wheels 51
Polishing device for engravers' steel plates 51
=Grindstones= and Tool Grinding 51
The various kinds of 51
Suitable for wood working tools 52
Suitable for saws or iron plates 52
The speeds of 52
The changes of pulley diameter necessary as the diameter of the
stone decreases in order to maintain a nearly uniform
circumferential speed of grindstone 52
Arrangement of, for saw plates 52
Hacking 53
Device for truing 53
Automatic traversing device for 53
Considerations that determine the position in which the work
should be applied to 53
=Oil-stones=, the various kinds of 54
Truing oil-stones 54
Removing the feather edge left by 54
Oil-stoning edge tools 54

CHAPTER XXIV.

=GEAR CUTTING MACHINES.=

=Gear Cutters=--The Brainard Automatic 55
Plan view of the mechanism 55
Method of operating the cutter slide 55
The arrangement of the positive feed shipping motion 55
Arrangement and construction of the dividing mechanism 55
The Brainard half automatic gear cutting machine 56
Gear cutting engine with vertical cutter spindle 56
Gear planing machine 56
Piat's French gear cutting machine 56 to 61