Sherline 1/8 Inch WW Collet 116008
1/8 Inch WW Collet
Collets provide a quick, easy method of mounting cylindrical parts or bar stock in the lathe with a great deal of centering accuracy. Each collet is actually a small, precision 3-jaw chuck that fits into a special tapered adapter in the headstock. A drawbar that passes through the headstock and threads into the back side of the collet will draw the collet up into the tapered adapter. The adapter causes the jaws of the collet to close down and grips the part to. Typically, collets provide a very accurate part mounting system, but each size collet can accommodate only a small range of diameters of approximately ±.001″ (.02mm).
WW collets differ from milling collets (P/N 3060) in that they have a hole all the way through the collet and drawbar. The maximum diameter stock that can pass entirely through the collet is 3/16″ or 4.5mm, although collets are available up to 5/16 and 8.0 mm. The WW collets that are larger than the through-hole diameter are also “pot” chucks.
Improve the accuracy of WW collets by taking a light cut across the entrance angle of the collet adapter with the headstock set at 20° using a boring tool as shown in figure 2 below. (Refer also to the instruction manual on taper turning and boring.) In most cases, however, collet adapters are accurate enough and do not require this truing operation. Note that the collets available from Sherline are accurate yet economical.
When checking runout of a WW collet it is imperative that you make sure all tapered mating surfaces of the spindle, adapter and collet are perfectly clean and smooth. Check your collets using a good quality gauge pin of exactly the size for that particular collet. You can measure runout as close as possible to the collet face using a 0.0001″ (tenths) indicator.
Sherline collets are numbered logically. Inch collets all begin with part number 1160 and then by two digits. These indicate the size in 64ths of an inch. For example, P/N 116004 is 4/64″ (1/32″).
These collets are not hardened. They are manufactured by Sherline and are built to standard WW specifications; however, we have come across collets that are called “WW” but will not fit our drawbar and adapter. The Sherline collets have a shank diameter of .312-.313 and a .275-40 thread. Sherline manufactures a slightly larger .315″ adapter and drawbar set (P/N 1163). This set accommodate some of these other brands of 8 mm collets.
Sherline WW collets are available in inch sizes by 64ths of an inch from 1/64″ to 5/16″. Metric sizes go from .3 mm to 8.0 mm by .1 mm increments.