Steady Rests on a Lathe. Supporting a Workpiece on a Lathe

Topics covered in Supporting a Workpiece on a Lathe;

What Is a Steady Rest on a Lathe

When turning workpieces that are long in length and small in diameter, or heavy workpieces with a large diameter, support is generally needed to prevent the part from springing or bending, or to relieve the load on the center points. The fixtures used for this purpose are called a steady rest. Supporting a workpiece on a lathe in this way is called steadying. Steady rests are important auxiliary attachments on a lathe.

Why Is a Workpiece Supported with a Steady Rest on a Lathe

Even if the free end of a long shaft is supported with a traveling (revolving) center, the pressure of the tool and the weight of the part will always cause the workpiece to deflect. Steady rests are used on a lathe to prevent this deflection.

The effect of the lathe tool during cutting and the weight of the workpiece cause a pressure to build up at the center points. Steady rests are also used to prevent this pressure.

How Is a Workpiece Supported with a Steady Rest on a Lathe?

To adjust the steady rest, which is mounted on the lathe as required, a certain section of the workpiece must first be turned to a suitable diameter. The set screws should be turned so that the jaws, which must lightly touch the workpiece, are advanced by the same amount. Otherwise the workpiece will rotate off-center. A dial indicator is used to check the runout. Based on the reading shown by the dial indicator, the jaws should be moved forward and back to ensure the workpiece rotates smoothly. Once smooth rotation is achieved, the locking screws should be tightened.

This adjustment should be carried out with the workpiece rotating at low speed. From the sound and vibration that occur during rotation, it is possible to tell whether the steady rest has been adjusted properly. The jaws should never be tightened more than necessary.

Types of Steady Rests on a Lathe

Fixed steady rests

Fixed steady rests have a base prepared to match the lathe bed ways, and can be clamped like a vise anywhere along the ways where needed.

Parts of a fixed steady rest (above). Click on the image to enlarge it.

A fixed steady rest is used when the workpiece is long and has a large diameter. For long, small-diameter workpieces turned between two centers, it is used to support one end of the part during facing, drilling, thread cutting, and boring operations.

Fixed steady rests have three jaws that provide support. These can be adjusted according to the workpiece. Four-jaw fixed steady rests have also been made for large workpieces (above).

Mounting the fixed steady rest on the lathe

A special mounting shoe is used to fix fixed steady rests onto the lathe bed ways. The fixed steady rest is placed on the bed ways and mounted with this clamping shoe. The video above shows how the fixed steady rest is mounted.

Facing and turning between centers with a fixed steady rest

Mount the end of the workpiece that will not be turned into the universal chuck. Pull the carriage back to the tailstock body. Clamp the fixed steady rest onto the lathe bed ways.

Good results are usually obtained if the steady rest jaws are first adjusted at a point on the workpiece near the chuck and then moved to the end. With this method, the steady rest is aligned with the axis of the workpiece.

Dial indicators are used to check runout when machining long shafts between the chuck and tailstock center. The runout detected by the dial indicator can be corrected either from the steady rest jaws, or by using a chuck with independent jaws and tightening each chuck jaw enough to eliminate the runout.

Next, loosen the locking screw of the fixed steady rest, open its jaws, move it a little further away from the chuck, and clamp it again.

You can hold sandpaper against the area closest to the end of the part to clean it of rust and oxides.

Move the fixed steady rest to the section you sanded and clamp it there.

 Apply a bit of oil to reduce the friction between the fixed steady rest and the workpiece.

Once the workpiece is supported at its end point, we can proceed to the facing operation. Facing must be done before drilling the center hole.

Mount the drill chuck onto the tailstock, bring it up, and drill the center hole. When drilling the center hole, it is enough for 2/3 of the center drill’s tip to enter.

And finally, we place the tip of the tailstock center into the center hole and lock the tailstock in place.

Follower (traveling) rests

A follower rest is used to prevent small-diameter cylindrical parts from flexing under the pressure of the tool during turning. The follower rest has two jaws that follow the tool during turning. At the start, to adjust the rest’s two jaws, a short section near the head end of the workpiece is turned to a suitable diameter.

Bolted onto the carriage, the follower rest moves together with the carriage. In this way, the support of the two jaws prevents the workpiece from springing up onto the tool.

Turning with a follower rest on a lathe (above)

In some cases, a follower rest and a fixed steady rest can be used together on the same workpiece. If the workpiece is long and small in diameter, both a fixed steady rest and a follower rest are used.