Bolts with nuts are useful where great strength is desired. There are three chief varieties, Fig. 230.
| Fig. 230. |
| a. Stove-bolt. |
| 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.
| Fig. 231. Machine-screws. |
| a. Flat-head. |
| b. Round-head. |
| c. Fillister-head. |
| d. Oval-countersunk-head. |
Plates, Fig. 232, include corner-irons, straight plates and panel-irons. These are made of either iron or brass and are used in fastening legs to the floor, in stiffening joints, affixing tops, etc.