Facing lathe tool

Below figure illustrates an H. So for machining different screw threads having different pitches separates tools are used to produce accurate threads. The nose of the tool is pointed, flat or rounded according to the shape of the root of the thread. The side clearance of the tool for cutting square thread is of prime importance in order to prevent the tool from interfering or rubbing against the vertical flank of the thread.

The cutting edge of the tool is exactly similar to an external thread cutting tool but the front clearance angle is sufficiently increased as in a boring tool.

The tool is a forged type orbit type and held on a boring bar. The point of the tool must be set square with the work. A facing tool removes metal by its side cutting edges. So no top rake in necessary in a facing tool. The figure shows H.

The length of the tool is , ,, and mm and the nose radius varies from 0. Grooving tool is similar to a parting-off tool illustrated in the figure. An ordinary lathe turning tool may sever the purpose where a copying attachment is used to reproduce the form of a template. Flat forming tools are made of two types:. These tools have their cutting edges ground to the shape of the groove, undercut, or thread to be cut.

Flat dovetail forming tools have a wider cutting edge corresponding to the shape desired. Dovetail end of the tool is fitted in a special tool holder.

These tools are preferred in production work as a very long cutting surface can be used resulting in longer tool life. The centre of the tool is set slightly above the centre line of the work to provide an effective front clearance angle on the tool. The tool will rub against the work if the centres are of the same height. Regrinding is done by grinding the flat only. A boring tool is similar to a left-hand external turning tool so far its cutting edge is concerned.

The tool may be a bit type inserted in a boring bar or holder, or forged type having a tool shank. The figure shows an H.

A boring bar is made of mild steel with slots or holes cut into it to accommodate the tool bit which is locked by an Allen screw. The amount of projection of the cutting edge of the tool from the centre of the bar determines the finished hole diameter of the work.

The bit is generally inserted at right angles to the centre line of the bar for boring a continuous hole passing from one end to the other end. The bit is set at a single to the axis projecting beyond the end of the bar for boring a blind hole. The counterboring operation can be performed by an ordinary boring tool. The tool cutting edge is so ground that it can leave a shoulder after turning. A counterbore having multiple cutting edges is commonly used. Undercutting or grooving tool has a point and form of the cutting edge exactly similar to the form of the required groove.

Clearance angle is given at all the sides of the tool. For the recessing groove cutting edge, the longitudinal feed is employed. The front clearance angle depends upon the bore of the work. A parting off tool is normally forged and used as bits for cemented carbide tipped tools. Parting off tool is made as narrow as possible to remove the minimum of metal. The width of the cutting edge range from 3 to 12 mm only. The length of the cutting tool which inserts into the work should be slightly longer than the radius of the bar stock being machined.

After the workpiece is fixed on the CNC lathe and the facing tool is mounted into the tool holder of the lathe carriage, when the tool rotating in the jaws of the chuck, it will feed perpendicularly across the part's rotation axis, to cut the workpiece to required length accurately.

CNC machines can provide power feed, which instead of hand feed to obtain smoother surface finish. Lathe facing is done using the turning lathe, while milling facing performed on the milling machine. In lathe facing, the part is rotating and cutting tool is stationary in the same position, while in milling facing, the facing tool rotates against the fixed workpiece.

The workpiece is generally cylindrical in lathe facing, while you can face rectangular or odd-shaped material to fabricate parts in cubes and other non-cylindrical shapes. The rigidity of the cutting tool is good, which is suitable for small turning tools and non-ferrous metal turning tools.

Welding type: it is connected through the welding process, the cutter head and rod are made from different materials, the carbide insert is inlaid on the rod. It is compact in structure and convenient in manufacture. It is suitable for all kinds of turning tools, especially for small tools. It is a commonly used tool in CNC lathe, and the cutter bar can be reused. High-speed steel tool: it is made of high speed steel and can be ground continuously, a general cutter for rough machining and semi finish machining.

Carbide tool: the blade is made of carbide, which is used to cut cast iron, non-ferrous metal, plastic, chemical fiber, graphite, glass, stone and ordinary steel. It can also be used to cut heat-resistant steel, stainless steel, high-speed steel, tool steel and other difficult materials.

Diamond: diamond blade has the advantages of high hardness and wear resistance, low friction coefficient, high elastic modulus, high thermal conductivity, low thermal expansion coefficient, and low affinity with non-ferrous metals. It can be used for precision machining of non-metallic brittle and hard materials such as graphite, high wear-resistant materials, conforming materials, high silicon aluminum alloy and other non-ferrous metal materials.

Other materials, such as cubic boron nitride tool and ceramic tool, are developing towards rough machining and intermittent cutting of high hardness alloy cast iron. Lathe Machine and Operations. Classification by Use. Turning Tool Turning tools are designed for removing the materials from the stock, a rough turning tool is used to remove the maximum amount of material and the finishing turning tool is serve for good surface quality, just remove a small amount, to make the piece more accurate.