A Homebuilt Metal Cutting Lathe


WARNING!
In today's litigious times, I feel I must make it clear that building or operating machine tools or other power equipment carries inherent hazards.  While proper safety equipment, good technique, and simple sense can go far to reduce the risk, nothing you can do is risk free.  The number of carpenters, machinists, mechanics, and others who work with power tools and equipment, my age and older, who are missing one or more fingers or a larger limb is sobering.  If you choose to follow in my steps and construct your own machine tools, or even if you buy commercially made tools, always remember that the tool will not watch out for you -- only you can do that.  The cautions for working around power tools have been published thousands of times -- I won't repeat them, except to say that tool parts can be repaired or replaced if they break.  The same can't generally be said for your fingers or your eyes.

Bottom line here: I can't be responsible for your actions.  If you buy a tool or make a tool, even one identical to the ones I describe here, and it bites you, it's your own fault.  If you can't be bothered to learn how to use tools safely, or can't hold yourself responsible for the consequences of your use of a tool, maybe you'd best stick to video games.  At least in a game, if you die, you get to try again.

Another of the many things I've been interested in for most of the past thirty years is machining.  I've always been fascinated with the process of cutting a steel part with a steel tool, with the accuracy obtainable from a machine built with less accurate parts, and with the concept of a tool that, like the lathe, can be used to "make itself" -- that is, all the turned parts of a lathe can, in theory, be turned on the lathe as it is built.  More on that theory later.

These pages will be used to chronicle my progress as I attempt to build a lathe of my own from scrap materials.  There are books about this; the best known is Dave Gingery's book on making your own lathe, but it is strongly dependent on casting parts, which means making a furnace to melt the pot metal, zinc, brass, and aluminum, making a flask in which to ram the casting sand, making patterns -- the list goes on.  My concept is based in part on Gingery's work, in part on a set of plans for a miniature model maker's lathe published in Popular Mechanics in the 1930s, in part on material found elsewhere on the Web about modifications people have made to Taig and Sherline miniature lathes and to larger lathes of various varieties, and in part on my own vision of what I want from a lathe.

The project is a team effort.  A friend, Mark, is making a nearly identical lathe at the same time, and we're sharing scrounging efforts and ideas.  It was he who found and gave me the original Popular Mechanics plans and suggested upscaling them, and I convinced him he'd get more lathe for similar money (if considerably more effort) than just buying a Taig.  His initial interest in a lathe is for making telescope parts, such as focusers and diagonal mirror mounts, from aluminum, so he has perhaps a little lower requirements than I do in terms of power, rigidity, and size -- but there's never anything wrong with having a lathe larger than you need, expect that it's harder to move around.

The final capabilities I'm after include single point threading in both English and metric sizes, long enough bed and large enough swing for light gunsmithing work, enough rigidity and power to turn steel as well as aluminum and brass, and the accuracy to make parts that are interchangeable in close tolerance applications.  My current target specifications are for a 24" bed, which should give about 14" between centers, a 6 1/2" center height (to use the British nomenclature -- here in the United States we'd call this a 13" swing) which will allow turning full length parts up to about 8" diameter over the cross slide (and 12" diameter for parts that don't have to pass over the carriage), a 1/4 HP or larger motor with V belt cone pulley drive for speed selection (possibly augmented with a dimmer switch speed control for the motor to give more precise control), 1/4" or larger tool bits, #2 and #3 Morse tapers in head and tail stock, and a bored through spindle to allow turning long stock.  I'm hoping to keep some things, like the tapers and spindle threads, standardized so I can use commercially available accessories -- I don't know that I want to go so far as to make a universal chuck from scratch, for instance -- and I plan to use as little outside machine tool assistance as possible.


Some Reference Materials

The Fonly Lathe -- "Ah, 'Fonly I had a lathe"
Nick Carter's Taig pages
Mini Lathe page -- Grizzly/Harbor Freight 7x10 with many details of construction
Grinding Lathe Bits -- a required skill for any lathe owner not rolling in money
Gingery's classic books -- start from melting scrap metal, and finish with a machine shop!
Building a Gingery type lathe -- as of August 2002 shows progress up to the point of using the lathe to make parts for itself.
Lathe Parts -- another Gingery style lathe, mostly completed with modification information

Please note: inclusion or exclusion of any pages in this list is not a judgment of the value of the page, just a statement about what came to mind when I was creating this page.

The Project

Starting point: the lathe bed (many pictures -- have patience while the page loads)
Straight and true: the ways
Along and across: the carriage
Follow my lead: the carriage lead screw
Bearings and support: the headstock
Perfect alignment: line boring
Turning point: the spindle
An afterthought: the tailstock
Hanging by a thread: thread cutting gears

Another Project:

The Super 'Fonly

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All material on this page and pages linked from this page within my web site is Copyright 2001, 2002 by Donald Qualls
External links are copyrighted by their creators; links from here do not imply ownership of that material.
If you have comments or suggestions, email me at silent1@ix.netcom.com