The Lathe Compound Rest of the Paralell Lathe

The Lathe Compound Rest of the Universal Paralell Lathe is a sliding and rotating body that is mounted on top of the machine.

We can also call it top slide.

It is mainly used for turning tapers, housing the tools of the lathe, making threads and getting very fine advances that are not possible with the longitudinal slide of the lathe.

The compound rest of the lathe is made of cast iron and has many parts, among which are:

The compound rest swivel base, which can be rotated and is divided into sexagesimal degrees, the compound rest body, and on this, the tool post.

In addition to these elements, we can find other accessories not more important than the previous ones, such as: the main screw or feed screw, the main nut, a gib strip, gib screws, the index ring, the tools post slide handwheel, lubrication devices and the tool post.

Main elements of the Lathe Compound Rest

The Compound Rest Swivel Base.
It is made of cast iron, has two functions, the first is to serve as a guide for the compound rest body or top slide of the lathe by means of a male dovetail and the second is the possibility of turning on the base of the cross slide of the lathe thus describing angles since its base is divided into sexagesimal degrees.

This function allows the processing of turning tapers on the lathe, but with a limitation: only we can turning tapers of a length equal to the maximum stroke allowed by this device.

The Compound Rest Body
Like the compound rest swivel base, it is made of cast iron, it slides over the base by means of a female dovetail and the gib strip that allows you to give it the necessary adjustment so that this element has no backlash.

In the compound rest body, the main screw of trapezoidal thread of left sense is lodged that allows its advance or retreat, in addition it counts on the index ring and a handwheel for its manual operation.

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Other Accessories

• The Main or Advance Screw: It is made of alloy steel, usually with left trapezoidal thread, the pitch of this screw is a multiple of 5 to facilitate the reading of the index ring.
• The Main Nut: It is made of high resistance bronze, it is housed in the compound rest swivel base of the lathe.
• The Gib Strip: It is a rhomboid rule at 60°, taper at one end, it is made of cast iron, its function is to give adjustment between the compound rest swivel base and the compound rest body, this is achieved by means of two head screws located at both ends of the lathe compound rest.
• The Index Ring: Which function is to give information about the pitch of the screw, ie gives a visual measure as to the advance or retreat of the screw of the lathe compound rest.
• The Handwheel: Allows the manual action of the lathe compound rest screw to move this device forward or backward.
• Lubrication devices: They are elements that allow to lodge lubricant in the parts that are in continuous friction or contact to this way to avoid their premature wearing down, these are located in strategic places of the compound rest.
• The tool post, which is the place where we hold the tools for turning jobs. The tool post is made possible by a screw that is anchored in the upper part of the compound rest body of the lathe.

With this information I hope to have explained in the best way the functioning and the elements that are part of the Lathe Compound Rest.

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