It is obvious that the form of bolt head shown in [Fig. 1616] is equally applicable to the longitudinal grooves as to the cross slots, enabling the bolt to be inserted, notwithstanding that the work may cover the ends of the longitudinal slots.
The round holes a, b, c, &c., in [Fig. 1612], are preferable to the square ones, inasmuch as they weaken the table less and are equally effective. Being drilled and reamed parallel the plugs that fit them may be passed through them to any desirable distance, whereas the square plugs being taper must be set down home in their holes, necessitating the use of plugs of varying length, so that when in their places they may stand at varying heights from the table, and thus suit different heights of work. Whatever kind of holes are used it is obvious that they must be arranged in line both lengthways of the table and across it, so that they will not come in the way of the ribs r, which are placed beneath it to strengthen it.
The longitudinal grooves are planed out to make them straight and true with the V-guides and guideways, so that chucking appliances fitting into the grooves may be known to be set true upon the table.
Fig. 1618.
In [Fig. 1618], for example, is shown an angle piece a having a projection fitting into a longitudinal groove, the screws whose heads are visible passing through a into nuts that are in the widened part of the groove, so that operating the screws secures a to the table. The vertical face of a being planed true, a piece of work, as a shaft s, may be known to be set in line with the table when it is clamped against a by clamps as at p, or by other holding devices. Angle pieces such as a are made of varying lengths and heights to suit different forms and sizes of work.
Fig. 1619.