1!\iL_ 1 R E COM MEN D E D l A THE P RAe T ~ C E-( ell) i1 t d • } of the setting rings on the face of the chuck to obtain an approxi- mate location. It is then a simple matter to make the final adjust- ment for ,~eater accuracy. Another use of a stationary steady is when an operation requires to be performed on the end of a bar. In such instances the distance from the chuck may be too great for machining to take place without additional support, and if drilling is required, the tailstock centre is not available. Thus to support L~e work by means of a steady, adjust the jaws to touch the work until it is running true, and then lock them.
Again, use plenty of oil between the steady jaws and the revolving work. fa.cepla.te Work. The remarks in regard to the mounti.'1g of chucks apply equally to faceplates and catch plates. Some castings or forgings are so shaped as to be difficult to hold in a chuck, but can be damped on a faceplate by straps and bolts utilising the holes and slots provided, but do not rely entirely upon these. Whenever possible use stops against the work to take the pressure of the cut. DI"i!iing and Reaming from the Taiistock. For these operations the work is gripped in a chuck or mounted on a faceplate. It is important L,1.at the drill be started true so that z..
hole concentric with the \~,Tork diameter is produced, and a common method em- ployed to attain this is by centre drilling before commencing normal drilling. An angle plate bolted on to the faceplate, on to which the work is mounted, is often useful for boring and facing operations. Always ensure that revolving work is securely fastened and that a balance weight is fitted to counteract the out-of-balance effect of the mounting units and work. The limitation of a twist drill as a cutting tool is that it follows its Use of Steadies. Long slender work, if unsupported between centres, will tend to whip or bend under pressure of the cutting action.
To preven~ tl-,is happening, a travelling steady should be OVln point which takes the line of least resistance. Incorrect grinding can cause additional inaccuracies by Cr) cutting edges being ground to different angles, (2) cutting edges of equal angles but different lengths, (3) ::utting edges of unequal angles and lengths causing the point to be off-centreo It is essential then to see [hat the radial components of the two cutting edges are equal so that they constrain the drill to follow a direct path, but if an accurate bore is required, a drilled.
hole should be enlarged by a single point tool and final size obtained by reaming~ employed~ When machir:ing black bar, first turn a short length of W.~e bar at the tailstock end to the: diameter required, and adjust the STeady jRWS to touch the v;~ork, then lock them in position. The javls will then support the v.;ork at the point of the cut all along the length. Keep javls \vell lubricated during the operation. A stationary steady can be set up at any point along the bed to support 2 long shaft. If the shaft is or black bar J a ring somew wider than the of the res:
must be turned as a bearing for the Straight shank reamers are held in a chuck, vFhile taper sha.nks may be inse:-ted into the tailstock spindlea The reamer should be fed carefully through the hole by rotation of the tailstock handwheel, usmg an ampk supply of lubricant when reaming steel. jaVys. If the shaft is slender, this can be a delicate operation, so that a sharp pointed. tool with 2 very light cut should be employedQ 16