(1.) Can the driving power be employed directly to shift the belts of a planing machine?(2.) Why are planing machines generally constructed with a running carriage instead of running tools?(3.) What objection exists in employing a train of spur wheels to drive a planing machine carriage?(4.) What is gained by shifting the belts of a planing machine differentially?(5.) What produces the screeching of belts so common with planing machines?(6.) What conditions favour the shifting of planing machine belts?5. Every part laid down has something to govern it that may be termed a "base"some condition of function or position which, if understood, will suggest size, shape, and relation to other parts. By searching after a base for each and every part and detail, the draughtsman proceeds upon a regular system, continually maintaining a test of what is done. Every wheel, shaft, screw or piece of framing should be made with a clear view of the functions it has to fill, and there are, as before said, always reasons why such parts should be of a certain size, have such a speed of movement, or a certain amount of bearing surface, and so on. These reasons or conditions may be classed as expedient, important, or essential, and must be estimated accordingly. As claimed at the beginning, the designs of machines can only in a limited degree be determined by mathematical data. Leaving out all considerations of machine operation with which books have scarcely attempted to deal, we have only to refer to the element of strains to verify the general truth of the proposition.
Director
There is a problem as to the principle of action in a Barker wheel, which although it may be very clear in a scientific sense, remains a puzzle to the minds of many who are well versed in mechanics, some contending that the power is directly from pressure, others that it is from the dynamic effect due to reaction. It is one of the problems so difficult to determine by ordinary standards, that it serves as a matter of endless debate between those who hold different views; and considering the advantage usually derived from such controversies, perhaps the best manner of disposing of the problem here is to state the two sides as clearly as possible, and leave the reader to determine for himself which he thinks right."And let that woman go? I tell you never. The very stones in the street would cry out at me! You hear that knocking at the door? Go and open it."Hetty clapped her hands joyfully.