b.

Carriage-bolt.

c.
Machine-bolt.] _Stove-bolts_ are cheaply made (cast) bolts having either flat or round heads with a slot for the screwdriver, like ordinary screws.
_Carriage-bolts_ are distinguished by having the part of the shank which is near the head, square.
_Machine-bolts_ have square, hexagonal, or button heads.
_Machine-screws_, Fig.

231, are similar to stove-bolts, but are accurately cut and are measured with a screw-gage.

The varieties are, _a_, flat-head, _b_, round-head, _c_, fillister-head, _d_, oval-countersunk-head, all with slots for screwdriver.
_Plates_, Fig.