The versatility of the lathe machine is put to good use by performing metal polishing operations on it. The usual method is to use abrasive polishing paper or polishing cloth that is held by hand and pressed upon the rotating metal part that has to be polished. Polishing may be necessary to achieve a smooth surface finish that is otherwise not possible by filing.
For polishing a metal piece in a lathe machine it is necessary to rotate the work piece at a very high speed, as high as 5000 feet in a minute, but since this might not be possible in all models of lathes, the thumb rule is to run the machine at its peak speed to get the results that are best with respect to the machine. However, the use of emery cloth on lathe machines for metal polishing is fraught with risks and safety hazards that can cause serious injuries to operators. There are some ways to minimize the possibilities of accidents that have been discussed in this article.
Why do accidents happen on lathe machines during polishing operations? The reason is that the emery paper or cloth strip that is held by hand gets entangled in the machine on the rotating parts that actually drags the operator’s hand into the rotating machine causing the accident. There are numerous incidents of damaged forearms of operators who have been unlucky to fall victims to such unwanted circumstances.
Whether it is a CNC lathe or a manual lathe the safety stipulation says that under no circumstances should the operator use emery cloth by hand during polishing. Setting up appropriate machine guards would discourage operators to perform manual polishing operations that can turn out to be very dangerous.
The possibilities of performing the polishing operations without using emery paper have to be explored with emphasis on the following points.
- Is it mandatory to use the lathe machine to perform the polishing operations or is it possible to get the desired surface finish by using some other machine tools?
- Can other methods of surface finish like honing, grinding etc be considered to give the equivalent quality of surface finish?
- Is the desired surface finish linked to the intrinsic quality elements that can affect the functionality of the work piece or is it just for cosmetic reasons?
If none of the answers are satisfactory and using emery cloth is the only option then the right methods of using it without holding it by hand has to be followed.
Polishing tool holders
A looped strip of emery cloth is clamped and held on the tool post of the lathe machine that is used for external deburring works only. Another method is to wound the emery cloth on the holding device or lathe chuck and then holding in a boring bar holder that is mounted on the tool post. In both the methods, the use of hands is completely eliminated.
In addition, the operator has to be trained in the safe methods of using emery cloth so that possibilities of unsafe operations are completely eliminated.