Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 42

Cramps are used to hold work on the bench, to hold together work in course of construction, to facilitate the making of articles in which tight and accurate joints are essential, to hold together glued joints until the glue is dry and hard, and for other purposes that suggest themselves. Their uses will be treated in detail as occasion requires, and in the meantime it will suffice to illustrate a few types commonly employed in workshops. A holdfast for temporarily securing work to the bench is shown by Fig. 107. This ranges in length from 12 in. to 16 in. The old-fashioned holdfast cramp is illustrated by Fig. 108; this is entirely of wood, and the cheeks of the cramp range in length from 6 in. to 16 in. Iron cramps are shown by Figs. 109 and 110, Fig. 109 being the ordinary G-cramp, of which different makes vary only in unimportant details; some, for instance, have a lever and screw instead of a thumbscrew, whilst Fig. 110 shows one of Hammer’s G-cramps with instantaneous adjustment, this being an improved appliance of some merit. The screw merely is pushed until it is tight on the work held in the cramp, and a slight turn of the winged head then tightens up the screw sufficiently. The sliding pattern G-cramp is illustrated by Fig. 111, this possessing an advantage similar to, but not as great as, that of Hammer’s cramp. Sash cramps and joiners’ cramps (non-patent) resemble Fig. 112, a lengthening bar being supplied with them at an increase in price of, roughly, 60 to 80 per cent. There are several makes and many differences in detail, but Fig. 112 illustrates the type. There are a number of patent cramps for sashes and general joinery, of which Crampton’s appliance (Fig. 113) is sufficiently typical. The right-hand jaw can be set at any position on the rack. When the work has been inserted the right-hand jaw is pushed against it tightly, and the lever handle gives instantaneous adjustment. The joiner has a choice between a very great number of cramps. When jointing up thin stuff, if an ordinary cramp is used, there is a great risk of the material buckling up, and the joint being broken. This risk is obviated largely by the use of the cramp shown in plan and side view by Figs. 114 and 115, which are sufficiently explanatory when it is said that the cross pieces slide upon the side pieces. one sliding bar being made immovable by iron pins placed in holes in the side pieces. In cramping very thin stuff, place a weight upon it before finally tightening the hand screw.

Fig. 104.—Braced Sawing Stool.

Fig. 105.—Bolted Sawing Stool.

Fig. 106.—Sawing Horse.

Fig. 107.—Bench Holdfast.

Fig. 108.—Wooden Holdfast Cramp.

Fig. 109.—G-cramp.

Fig. 110.—Hammer’s G-cramp.

Fig. 111.—Sliding G-cramp.