7 Centre Lathe Machine Attachment that enhance Lathe Applications
Why Attachments are Necessary ?
Each general purpose conventional machine tool is designed and used for a set of specific machining work on jobs of limited range of shape and size. But often some unusual work also need to be done in a specific machine tools, e.g. milling in a lathe, tapping in a drilling machine, gear teeth cutting in shaping machine and so on. Under such conditions, some special devices or systems are additionally used being mounted in the ordinary machine tools. Such additional special devices, which augment
the processing capability of any ordinary machine tool, are known as Attachments, Unlike accessories, Attachments are not that inevitable and procured separately as and when required and obviously on extra payment. Some attachments being used in the general purpose conventional machine tools are :
Taper turning attachment – Taper cylindrical surface, which is a very common feature of several engineering components, is generally produced in lathes in a number of methods, depending upon length and angle of the tapered position of the job, such as offsetting tailstock, swivelling the compound slide using form tool and combined feed motions. But jobs with wide ranges of length and angle of taper, are easily machined by using a simple attachment, called taper turning attachment. Fig. schematically shows a taper turning attachment where the cross slide is delinked from the saddle and is moved crosswise by the guide block which moves along the guide bar preset at the desired taper angle. Thus, the cutting tool, which is fitted on the cross slide through the tool post and the compound slide, also moves along with the guide black in the same direction resulting the desired taper turning.
2) Copy turning attachment
There are two common types of copy turning;
A simple mechanical type copy turning attachment has been schematically shown in Fig.. The entire attachment is mounted on the saddle after removing the cross slide from that. The template replicating the job-profile desired is clamped at a suitable position on the bed. The stylus is fitted in the spring loaded tool slide and while travelling longitudinally along with saddle moves in transverse direction according to the template profile enabling the cutting tool produce the same profile on the job as indicated in the Fig.
3 ) Milling attachment
This is a milling head, comprising a motor, a small gear box and a spindle to hold the milling cutter, mounted on the saddle after removing the cross slide etc. as shown in Fig. Milling attachments are generally used for making flat surfaces, straight and helical grooves, splines, long and deep screw threads, worms etc. in centre lathes by using suitable milling cutters.
4) Grinding attachment
Grinding attachment is very similar to milling attachment. But in the former, there is no gear box and the spindle speed is much higher as needed for grinding operation. Such attachments are employed for external and internal cylindrical grinding, finishing grooves, splines etc. and also for finish grinding of screw threads in centre lathe. But unlike dedicated machines, attachments cannot provide high accuracy and finish.
5) Spherical turning attachments
These simple attachments are used in centre lathes for machining spherical; both convex and concave surfaces and similar surfaces. Fig. schematically visualizes the usual setting and working principle of such attachments.
6) Relieving attachment
The teeth of form relieved milling cutters like gear milling cutters, taps, hobs etc. are provided with flank having archemedian spiral curvature. Machining and grinding of such curved flanks of the teeth need relieving motion to the tool (or wheel) as indicated in Fig.
The attachment schematically shown in Fig. is comprised of a spring loaded bracket which holds the cutting tool and is radially reciprocated on the saddle by a plate cam driven by the feed rod as indicated.
There are many of lathe accessories including various centres, extensions & tool rests also various type of tool holder, chuck, headstock. Similarly to this principal we design Multipurpose indexing device. This device is generally used for lathe tool post. Our project is depending upon the worm and worm gear for the indexing purpose to index the tool post.
Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.