TWO:The maneuver was executed, ending in a fairly tight circle after Jeff had skilfully leveled out of the drop.
TWO:Milling relates to metal cutting with serrated rotary cutters, and differs in many respects from either planing or turning. The movement of the cutting edges can be more rapid than with tools which act continuously, because the edges are cooled during the intervals between each cut; that is, if a milling tool has twenty teeth, any single tooth or edge acts only from a fifteenth to a twentieth part of the time; and as the cutting distance or time of cutting is rarely long enough to generate much heat, the speed of such tools may be one-half greater than for turning, drilling, or planing tools. Another distinction between milling and other tools is the perfect and rigid manner in which the cutting edges are supported; they are short and blunt, besides being usually carried on short rigid mandrils. A result of this rigid support of the tools is seen in the length of the cutting edges that can be employed, which are sometimes four inches or more in length. It is true the amount of material cut away in milling is much less than the edge movement will indicate when compared with turning or planing; yet the displacing capacity of a milling machine exceeds that of either a lathe or a planing machine. Theoretically the cutting or displacing capacity of any metal or wood cutting machine, is as the length of the edges multiplied into the speed of their cutting movement; a rule which applies very uniformly in wood cutting, and also in metal cutting within certain limits; but the strains that arise in metal cutting are so great that they may exceed all means of resisting them either in the material acted upon, or in the means of supporting tools, so that the length of cutting edges is limited. In turning chilled rolls at Pittsburg, [141] tools to six inches wide are employed, and the effect produced is as the length of the edge; but the depth of the cut is slight, and the operation is only possible because of the extreme rigidity of the pieces turned, and the tools being supported without movable joints as in common lathes."I am afraid of her; I mistrust her; she frightens me. Call it prejudice if you like, but there is something wrong about that woman. Did she find out anything about us last night, Gordon?"
TWO:
TWO:For milling, drilling or boring ordinary work within its range, a lathe is by no means a makeshift tool, but performs these various operations with nearly all the advantages of machines adapted to each purpose. An ingenious workman who understands the adaptation of a modern engine lathe can make almost any kind of light machinery without other tools, except for planing, and may even perform planing when the surfaces are not too large; in this way machinery can be made at an expense not much greater than if a full equipment of different tools is employed. This of course can only be when no division of labour is required, and when one man is to perform all the several processes of turning, drilling, and so on. Possibly the world may move, and possibly it may be at rest. Possibly it may be round, or else it may be triangular, or have any other shape. Possibly the sun and the stars may be extinguished at setting, and be lighted afresh at their rising: it is, however, equally possible that they may only disappear under the earth and reappear again, or that their rising and setting is due to yet other causes. Possibly the waxing and waning of the moon may be caused by the moons revolving; or it may be due to the atmospheric change, or to an actual increase or decrease in the moons size, or to some other cause. Possibly the moon may shine with borrowed light, or it may shine with its own, experience supplying us with instances of bodies which give their own light, and of others which have their light borrowed. From these and such like statements it appears that questions of natural science in themselves have no value for Epicurus. Whilst granting that only one natural explanation of phenomena is generally possible, yet in any particular case it is perfectly indifferent which explanation is adopted.169