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View Full Version : So you want to buy a metal lathe



dan s
10-15-2008, 03:21 AM
As i said in another thread, I thought it would be a good idea to come up with a non biased guide with what to look for when buying a lathe.

Please feel free to contribute or offer comments as you see fit.


This is what i came up with tonight and it's still pretty rough, but it's a start.

So you want to buy a metal lathe

This guide is an attempt to help beginners & semi-knowledgeable individuals, determine what size, and features they need in a manual metal lathe. The guide does not address the quality or lack thereof for specific makes or models, only general terms and concepts associated with making an informed purchase. It also does not address what to look for when buying a used lathe that might need some level of refurbishment.

Major lathe components:
{insert labeled pictures}

Bed - Main supporting casting running the length of the lathe, that all other are parts attached to or ride on.

Ways - Precision ground surfaces along the top of the bed on which the various other components ride. The ways are precisely aligned with the centerline of the lathe.

Headstock - The main casting mounted on the left end of the bed, in which the spindle is mounted. The headstock can also contain gears or belts that control the rpm of the spindle.

Spindle - The Main rotating shaft on which the chuck or other work holding device is mounted. It is mounted in precision bearings and passes through the headstock. The spindle is usually hollow to facilitate passing small stock through the headstock.

Carriage – The carriage is a general term used to refer to a grouping of sub components. The sub components that comprise the carriage are saddle, cross slide, compound, rest, & apron.

Saddle - A casting, shaped like an "H" when viewed from above, which rides along the ways. Along with the apron, it is one of the two main components that make up the carriage.

Cross slide – A sub component that rides on the saddle, and moves perpendicularly to the bed.

Apron – The apron is essentially a housing attached to the underside of the saddle, that contains gears, clutches, dials, and levers used to both manually and automatically propel the carriage and cross slide.

Compound rest – The compound rest is fastened to the cross slide in such a way that it can be rotated a full 360 degrees. The compound usually has a travel of a few inchs and can only be actuated manually. This allows for two things the turning of short tapers and more precise in-feed control than can be obtained from the cross slide. The tool post mounts to the top of the cross slide.

Tool post – The tool post’s primary function is to securely hold the cutting tool at the proper height and angle to facilitate efficient material removal.

Lead screw - A precision screw that runs the length of the bed, that is used to precisely drive the carriage during the thread cutting process. Small lathes also use the lead screw to drive the carriage during the turning process; large lathes have an additional component for this called a feed rod that thus reduced the wear on the leadscrew.

Gear box – The gear box is connected to the spindle via gears, and is used to precisely control the rpm ratio of the lead screw to the spindle.

Tailstock – The tail stock is used to hold drills, reamers, and other cutting tools, as well as support long workpieces.

coldformer
10-15-2008, 05:25 AM
try this
http://www.mermac.com/advicenew.html

oldtiffie
10-15-2008, 06:10 AM
That's a good guide at that link coldformer - thanks.