Sharpening Metalworking Tools

Lathe Tools. In the small workshop the sharpening of the turning tools is a matter of the greatest importance, and one which the tyro often finds the most difficult ; nevertheless, on it very largely depends the accuracy and the general quality of the lathe work undertaken.

A blunt or incorrectly sharpened tool may well cause undue heating and distortion of the work, as well as a ragged and torn surface finish.

Those who perforce rely on foot power for operating the lathe soon learn to their cost that an increased output of energy is required to operate a blunt tool, or one that has its cutting edges incorrectly formed ; but, on the other hand, they quickly come to appreciate the value of a properly sharpened tool.

Although in factories a high rate of output must be maintained by working robust tools up to their maximum capacity consistent with accuracy, in the small workshop the operator may seek rather to obtain results of high quality irrespective of the time spent, and for this reason he forms his turning tools to give free-cutting and a good surface finish.

Some workers never advance beyond the stage of grinding their lathe tools by the free-hand method and trusting to the eye to determine the form of the tool. Although many may find this procedure perfectly satisfactory, there is much to be said for the accuracy and uniformity obtained when an adjustable form of tool-rest or grinding jig is used to set the cutting angles automatically.

Before going further, it may be helpful to examine in detail the more common tool forms in general use.

The shape of the tool-tip presented to the work is determined by the angles to which the cutting edges are ground, and although these will vary in their disposition in accordance with the purpose for which the tool is used, they will, nevertheless, remain substantially of the same value in all tools used for machining any particular material.

The essential angles concerned in a tool's formation are termed clearance and rake angles.

The Clearance Angle. Wherever the cutting edge of the lathe tool comes in contact with the work, clearance must be provided behind this edge to ensure that it alone makes contact with the work surface ; otherwise, the tool will tend merely to rub and will not cut freely.

In Fig. 19a. where the tool is viewed from the position of the tailstock, the front clearance between the tip of the tool and the work surface is shown ; whilst, when looking along the tool from the front of the lathe, the side-clearance provided in the direction of the tool's travel is illustrated in Fig. 19b.

The clearance angle, then, is not concerned with the actual cutting process, but merely ensures that the cutting edge alone makes contact with the work.

The Rake Angle. In this case, the tool surfaces concerned are those against which the chips impinge as they are sheared from the work surface. Further reference to Figs. 19a and b will show that the top rake is the angle of the backward slope of the tool's upper surface from the front cutting edge. Likewise, the side rake is the angular slope away from the work in relation to the side-cutting edge.

The Knife Tool. The tool shown in Fig. 19a, b and c is a typical knife tool, and when it is formed to cut towards the headstock of the lathe it is termed right-handed, and when in the reverse direction left-handed.

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Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

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