in forming it, and make it rough and dull, instead of sharp. When the edge of a filed tool is tempered it is apt to crumble, and is, in many other respects, inferior to one that is ground.

For turning a moulding or bead on a side pipe, or cylinder head, such as the one shown in this figure, it will be found convenient to make the

beading tool on the spring plan, illustrated in fig. 60. By this method it is less likely to chatter, or leave ridges, or cut roughly.

Of tools other than those used for cutting wrought and cast iron, there are few which are materially different in external appearance. To this statement there is one exception. Brass cannot be cut by the same tools that are used for iron. Below, in fig. 72, we give examples of tools for turning brass. It will be seen that they are perfectly straight on the upper faces, and have no lips or acute edges. It is not possible to cut brass with

a drill, or any other tool that has a cleaving edge. Such edges draw in to the metal and throw it out of the lathe, or else jam and break off. There are

Fig. 72.

compositions of copper and tin, zinc and copper, and others, which can be cut by common tools, but these are not brass, which consists of specific portions of certain metals. One of these toolsthe round nose-is used for light cuts, and the other where large amounts of metal have to be taken off at once.

In turning wrought-iron very many turners make their tools quite hard, and cut the metal dry or without water; preferring to absorb power rather than soil the lathe with sloppy combinations of iron and water. With proper care but little "muss" will be made, while the gain in time, by using water, is very apparent. Not less important is the power required to drive a given number of lathes. Those which run dry require more than tools used with water, for the simple reason that the friction is greater. Any one can test this to

his entire satisfaction by putting a tool in a lathe, starting the cut, and driving the machine by hand. It will be found that when the chip is of such a size that the arm can hardly turn the lathe dry, the addition of water will free it immediately, and the lathe can be driven with ease. If the shears be well oiled previous to beginning a job, the water can be wiped off without injury to them, even though the work be days in progress.

This chapter concludes the series on this subject. The skilled turner will perceive many cases not laid down under this head which might have been alluded to, but it is impossible within the limits of our treatise to detail every minute manipulation a lathe is capable of. Special instruction on particular points has not been aimed at, but a

general and familiar treatise on the tools used in turning.

PART III.

MISCELLANEOUS TOOLS AND PROCESSES.

CHAPTER XIV.

LEARN TO FORGE YOUR OWN TOOLS-MANUAL DEXTERITY-SPARE THE CENTRES.

MANY mechanics have an idea that after they have mastered the more legitimate duties of the workshop, they have learned all that is necessary and can undertake any thing in their line of business. Machinists particularly are prone to this error-a common one by the way--and think that a knowledge of fitting and turning, once acquired, makes up for all other deficiencies. In reality, the self-styled finished mechanic is, paradoxically, the unfinished one; for he who acknowledges his shortcomings, and tries to correct them by obtaining all the information he can, will acquire a more thorough knowledge of his pro fession. Comparatively few machinists are competent to dress their own tools, or, indeed, handle the blacksmith's hammer on any work. How many times such knowledge would have been invaluable, we leave individuals to decide from their own experience. A simple weld which they

were unable to make, a faculty for dressing chisels without putting their own eyes in danger by striking the anvil instead of the tool, would assuredly have stood persons ignorant of such details in good service in time of need. Apprentices who go to the tool-dresser to have the edges of their chisels or other instruments renewed, will do well to observe the process and inform themselves of it. Observation and experience are twins and inseparable, and no youth, or indeed any adult, can hope to attain eminence or proficiency without paying some respect to the matter herein alluded to.

Nothing looks more slovenly or impairs the value of a tool quicker than the accumulation of dirt and grease in its joints or about its bearings. The filthy oil that most manufacturers use, from a mistaken idea of economy, forms a glutinous mass outside of the bearings of lathes and other machinery, in which cast and wrought-iron dust and grit collects, to the great detriment of the working parts. Aside from this fact, the drill shavings and chips from cutters, if allowed to gather in the bed, or about the foot of the tools in question, give the shop a slovenly appearance, which greatly prejudices it in the minds of ob serving people. A lathe or planing machine that is clean will do twice the work that a dirty one will, at less cost often; and over and over again we have watched some clumsy fellow wading