Practical Carriage Building

Compiled by M.T. Richardson, Vol.1. 1891

Screw Drivers

The screw driver is an important tool, but there are few that are properly ground. Most body makers grind them wedge shape, and then wonder why they cannot “send the screw home.” If they will look at the slot in the screw head, they will see that it is as broad at the bottom as at the top, and that if a screw driver is to hold well, it must be ground to fit the slot. If ground that way, and then roughened by a few lines across the faces, it will hold the screw and will not split the head, as is often done by the wedge-shaped screw driver. Figs. 12 and 13 show the proper form for a screw driver point.

Hand screw drivers are always needed. The remarks regarding grinding them are as pertinent as to the brace screw driver bit. Braces receive too little consideration from the body maker. So long as they hold the bit, they are made to answer, even though of the most inferior quality. The old-fashioned wood brace is convenient for light work, but the bits must be well fitted. The patent ‘compressed sleeve’ iron brace is the most convenient. There is no trouble fitting any bit, and it is sure to hold. For general use it should have about six- inch crank. The ‘compressed sleeve’ and ‘reversible ratchet’ braces are indispensable, as with them holes can be bored at almost any point, for the sweep of the crank can be got out of the way so that a hole can be bored in corners or elsewhere. If the body maker cannot afford to have but one brace, that one should be the ‘reversible ratchet.’

Screw Driver Point Form Figure 12-13

In addition to the regular lines of tools mentioned, there are others equally necessary, many of which cannot be purchased at the toolmakers’, unless made to order, and as a rule better results are attained by the body maker making them for himself than when made by the toolmaker. Those of metal throughout must be made by the toolmaker, but the body maker must provide a perfect model. The rabbet knife is of the latter class. It is a tool that cannot be dispensed with. There are numerous forms, but for general use one with a blade as shown by Fig. 14 will be found the most satisfactory. The arms should be bow-shaped and heavy enough to work without springing. The bit should not be less than two and a quarter inches on the cutting edge. As will be noticed, the bevel is ground on the upper side, the face being true and edge low so as to bite quickly. The form of the face is such that the knife works well upon straight and concave surfaces, and in the absence of another pattern, can be used on convex surfaces. The arms should not be less than eight inches long in the clear between the handle and the blade.




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