Head stock with cross travel.

In passing, an important detail in construction, which is also described elsewhere, is our scheme of gibbing, which puts the gib and its thrust-taking screws under severe tension, even when adjusted for the free movement of the slide. The object is to see that all of the spring of the bolt and gib is taken up before the strain of the work comes on it, and although this is only a detail, it is one of the one hundred or more points on which the success of a machine of this kind stands.

The conservative man frequently asks : How is it possible to return this head to its central position ? It is only necessary for us to call attention to the fact that for years we have been turning the turret around to six different positions with a satisfactory accuracy, under conditions more difficult to control than the present single direct slide ; and to furthermore state that we not only bring this cross slide with accuracy to its central position, but by an ideal scheme of stops it is possible to bring it to as many other positions as called for by the work with the same nicety, and that these details are elsewhere described.

Return of head to central position.

Just as our experience with the cutting tool in the engine lathe shapes our views of its endurance and capacity for doing good work under heavy cuts, just so our experience with former types of special machines comes to mind whenever a machine of this kind is to be considered. We know that a special machine usually requires special tools, and although this is not apparently a serious objection, owing to our usual hopefulness that there will be no immediate change in the kind of work we are to do, yet even with no change of work in view, the question of special tools, both from the side of expense and delay, is a serious barrier to the adoption of many of the special lathes that are now offered, and it is no uncommon experience to find a machine standing two of three months waiting for some special tools for a given piece of work and frequently a very slight change in the character of the work makes it necessary to throw away or set aside all of the tools in such a machine's equipment. The practical man, therefore, is ready to admit all the theorist may say regarding firmness of control, ideal conditions of slides and anti-cob-house construction, but he will say: "Deliver me from the toils of such a tempter; I have not lived to this point in vain, and I cannot forget my experience with special machines."

The machine described on pages following page 69 is provided with an equipment of standard tools which it holds under absolute control, conveniently and quickly adjusted, and it puts an end to the foreman's difficulties in getting out the class of work coming within its range, regardless of any changes that may be made in the design or the number of

Long delays required by special.

The pieces to be made; and it is safely described as the "any" machine; that is, it is ready any hour of any day to make any piece of any shape and any quantity coming within its working dimensions, with an accuracy and efficiency never before attained. This adaptability to all conditions not only gives a ready relief for the troubles of to-day but it also makes progressive designing possible.