Difference Between Turret and Engine Lathes

Difference Between Turret and Engine Lathes

Difference Between Turret and Engine Lathes - Whereas turret lathe is adapted to quantity production work, engine lathe is primarily used for miscellaneous jobbing, tool room or single operation work. Another difference between an engine lathe and turret is that the tailstock is replaced by a (usually) hexagon turret upon which are bolted various toolholders for knee turning, roller box turning, drilling, boring and recessing.

Unlike engine lathe, a turret lathe can hold a number of cutting tools at a time. In engine lathe one tool cuts at a time whereas in turret, a number of tools can operate on the job simultaneously. Tools may be permanently set up in the turret in the sequence in which they need be used.

Extreme rigidity in the holding of work and tools is built into the turret lathe to permit multiple land combined cuts. Using a turret lathe instead of an engine lathe can often cut machining time by 25 to 75% and handling time by 2550%.

Unlike an engine lathe a turret lathe has

(i) a front tool post which holds four tools that may be indexed by 90°. so that every 1001 can operate upon the workpiece in a regular order and

(ii) a rear tool post mounted upon the carriage which holds another tool e.g., for cutting off operation.

If large number of pieces are to be manufactured, every time positioning and changing of tools for each job on an engine lathe not only involves a good deal of time but may also result in workpieces of non identical dimensions.

Frequent tool changing is not needed on a turret lathe, because several tools can be mounted on the hexagonal turret and tool post and can be preset as per the requirements of various operations to be carried out on workpieces on mass scale.

Unlike engine lathe, the feed movement of each tool set on hexagonal turret is regulated by stops and feed trips. The tools operate on the workpiece for a predetermined amount (e.g., length etc.).

The original cost of a turret lathe is considerably higher than that of the engine lathe. Tooling is expensive and setup time will run from 12 hours on small jobs up to 8 hours for a complex job. Machining time on turret lathe, as compared with an engine lathe, is not shortened. Feeds and speed remain the same for all types of lathes.

The time saving on turret lathe is principally because of the combined cuts and because so much machining can be done with only one chucking of the part. For example, the cross slide tools may be turning one diameter while toe turret tools are boring and turning other diameters. Unlike engine lathe, a semiskilled operator can operate a turret lathe or a Capstan lathe after the same has been set up by a skilled worker.