pping Devices_
_Fig. 79. Anchor Bolt_
_Fig. 80. Lazy Tongs._
_Fig. 81. Disc Shears._]

Fig. 82. WABBLE SAW.--This is a most simple and useful tool, as it will
readily and quickly saw out a groove so that it is undercut. The saw is
put on the mandrel at an angle, as will be seen, and should be run at a
high rate of speed.

Fig. 83. CRANK MOTION BY A SLOTTED YOKE.--This produces a straight
back-and-forth movement from the circular motion of a wheel or crank. It
entirely dispenses with a pitman rod, and it enables the machine, or the
part of the machine operated, to be placed close to the crank.

Fig. 84. CONTINUOUS FEED BY THE MOTION OF A LEVER.--The simple lever
with a pawl on each side of the fulcrum is the most effective means to
make a continuous feed by the simple movement of a lever. The form shown
is capable of many modifications, and it can be easily adapted for any
particular work desired.

[Illustration: _Fig. 82. Wabble Saw_
_Fig. 83. Continuous Crank Motion_
_Fig. 84. Continuous Feed_
_Fig. 85. Crank Motion_
_Fig. 86. Ratchet Head_
_Fig. 87. Bench Clamp_]

Fig. 85. CRANK MOTION.--By the structure shown, namely, a slotted lever
(A), a quick return can be made with the lever. B indicates the fulcrum.

Fig. 86. RATCHET HEAD.--This shows a well-known form for common ratchet.
It has the advantage that the radially movable plugs (A) are
tangentially disposed, and rest against walls (B) eccentrically
disposed, and are, therefore, in such a position that they easily slide
over the inclines.

Fig. 87. BENCH CLAMP.--A pair of dogs (A, B), with the ends bent toward
each other, and pivoted midway between the ends to the bench in such a
position that the board (C), to be held between them, on striking the
rear ends of the dogs, will force the forward ends together, and thus
clamp it firmly for planing or other purposes.

[Illustration:
_Fig. 88. Helico-Volute Spring_
_Fig. 89. Double Helico-Volute_
_Fig. 90. Helical Spring_
_Fig. 91. Single Volute Helix-Spring_
_Fig. 92. Flat Spiral or Convolute_
_Fig. 93. Eccentric Rod and Strap_
_Fig. 94. Anti-Dead Center for Foot-Lathes_]

Fig. 88. HELICO-VOLUTE SPRING.--This is a form of spring for tension
purposes. The enlarged cross-section of the coil in its middle portion,
with the ends tapering down to the eyes, provides a means whereby the
pull is transferred from the smaller to the larger portions, without
producing a great breaking strain near