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HOW TO CHOOSE A SELF-CENTERING LATHE CHUCK

- Tools

A GOOD QUALITY CHUCK CAN ENSURE THAT ALL LATHES WILL PERFORM BETTER.

The main requirements for a lathe chuck is to securely and safely hold the job in the lathe, be accurate and maintain accuracy over a long time.

Understanding the difference between ultimate cost and immediate price is an important factor in selecting a lathe chuck. A lathe chuck should be selected according to the quality of the important features of GRIP; ACCURACY and WEAR LIFE. High quality of these feature means that the chuck will outlast a low price but low quality chuck many times over meaning much lower ultimate cost.

GRIP The better the grip, the safer is the work environment and the faster the job can be done.

Several factors affect the grip:

SMALL-DIAMETER-CHUCK
Figure 1 SMALL DIAMETER CHUCK SHOWING PITCHES OF EXPOSED SCROLL TOOTH

ACCURACY

Consider the accuracy the maker claims. Not all chucks have the same run-out accuracy when being operated. Some makes of chucks offer different accuracies for job run-out. A good quality chuck should have a run-out not exceeding 40 microns (0.001”) at any position on the scroll for sizes up to and including 315mm diameter. For 400mm diameter chucks a run-out of .075 microns is permissible. For 500mm or 600mm diameter chucks run-out of 0.10 microns is permissible. If the claimed run-out accuracy is MORE than these values then it is not a precision chuck.

WEAR LIFE & FINISH

The finish of a chuck will give a good indication of the quality. Look for “ground” finish on the chuck body and a blemish-free surface. The life of a chuck is determined by the selection of correct materials, accuracy of manufacture and finish of the various components and how these components work together. Lathe chucks should be regularly cleaned and re-lubricated using grease for the scroll and pinion and oil for the scroll and jaws. NEVER use graphite or graphite-based grease to lubricate a precision chuck, scroll and pinions.

SUMMARY

The following should be checked when selecting a lathe chuck

JAW-IN-CHUCK-BODY

Figure 2 END VIEW OF JAW IN CHUCK BODY SHOWING REAR JAW TOOTH AND START OF SCROLL TOOTH

 

 

 

ROBINSON INTERNATIONAL PTY LTD

www.robinsoninternational.com.au

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