collet chucks () are very accurate work-holding devices and are used in producing small high-precision parts. steel spring collets are available for holding and turning hexagonal, square, and round workpieces. they are made in specific sizes (which are stamped on them) with a range of only a few thousandths of an inch. workpieces to be gripped in a collet should not vary more than +.002 to -.003 in. from the collet size if the expected collets to hold cylindrical work to .0005 in. eccentricity (indicator runout). rough and inaccurate workpieces should not be held in the collet chuck since the gripping surfaces of the chuck would form an angle with the workpiece. the contact area would then be at one point on the jaws instead of along the entire length, and the piece would not be held firmly. if it is not held firmly, workpiece accuracy is impaired and the collet may be damaged. An adapter called a collet sleeve is fitted into the spindle taper and a draw bar is inserted into the spindle at opposite end () the collet is placed in the adapter, and the draw bar is rotated, which threads the collet into
the taper and closes it. naver tighten a collet without a workpieces in its jaws, as this will damage it. before collets and adapters are installed, they should be cleanedto ensure accuracy.
the rubber flex collet() has a set of tapered steel bars mounted in rubber. it has a much wider range than the spring collet, each collet having a range of about 1/8 A large handwheel is used to open and close the collets instead of a draw bar ()
the concentricity that you could expect from each type of work-holding device is shown in table I-3
collet chucks () are very accurate work-holding devices and are used in producing small high-precision parts. steel spring collets are available for holding and turning hexagonal, square, and round workpieces. they are made in specific sizes (which are stamped on them) with a range of only a few thousandths of an inch. workpieces to be gripped in a collet should not vary more than +.002 to -.003 in. from the collet size if the expected collets to hold cylindrical work to .0005 in. eccentricity (indicator runout). rough and inaccurate workpieces should not be held in the collet chuck since the gripping surfaces of the chuck would form an angle with the workpiece. the contact area would then be at one point on the jaws instead of along the entire length, and the piece would not be held firmly. if it is not held firmly, workpiece accuracy is impaired and the collet may be damaged. An adapter called a collet sleeve is fitted into the spindle taper and a draw bar is inserted into the spindle at opposite end () the collet is placed in the adapter, and the draw bar is rotated, which threads the collet into
the taper and closes it. naver tighten a collet without a workpieces in its jaws, as this will damage it. before collets and adapters are installed, they should be cleanedto ensure accuracy.
the rubber flex collet() has a set of tapered steel bars mounted in rubber. it has a much wider range than the spring collet, each collet having a range of about 1/8 A large handwheel is used to open and close the collets instead of a draw bar ()
the concentricity that you could expect from each type of work-holding device is shown in table I-3
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