The construction of the saw guides is shown in [Fig. 3138], which is a plan view partly in section. s s are hardened steel plates set up to the saw by means of studs whose nuts are shown at n n. w is a friction wheel which supports the saw against the thrust caused by the work feeding to the saw. The adjustment of the wheel w to the saw is obtained by means of the wheel h.
The hand wheel h operates the screw r r, that adjusts the wheel w to the saw, the wheel j serving to lock the screw in its adjusted position.
[Fig. 3139] represents Worssam’s band saw machine, in which the standard may be set at any required angle for cutting bevels.
When the work is heavy and not easily handled it is preferable to set the standard and saw at the required angle, rather than to set the table at an angle and have the saw remain vertical. In Worssam’s machine this is accomplished as follows:
a is the main frame carrying the work table t, and having circular guideways b, b′, which carry the standard c having guide c′ for working in the circular guideways b, b′.
The saw-driving wheel d, is carried in bearings provided in c, and, therefore moves when the standard c is moved.
At the upper end of c, is the slide e, which carries the bearing for the upper wheel f, this slide being adjusted to regulate the saw tension by the hand wheel o, whose screw threads into a nut in the slide e. h carries the front guide g, for the saw, the back guide g′ being carried by a bracket bolted to c. The back guide is fixed in position, but the front one is adjustable to suit the height of the work by raising or lowering it.
The means for setting the saw at the required angle to the work table are as follows:
At the back of the standard c is a rack j, whose pitch line is an arc of a circle of which the axis of the guideway c′ is the centre.