View Full Version : My Lathe Project

08-28-2006, 12:45 PM
My Lathe Project Β©2006


This lathe design is based on the South Bend 9” Metalworking lathe as well as comments and notes taken from observing metalworking and machining forums across the Internet. I wanted no smaller than a 6” lathe but no bigger than a 16” lathe. I just don't have the room for any bigger.

I saw that the Logan and Monarch lathes are also popular. The other types are Taig and Unimat. There are hoards of others I guess, and a lot of clones, as well as Chinese imports and others. I wanted to make a lathe with the best of the the best sort of thing.. and it still be accurate as well as affordable.

Here are my preliminary findings on the project.

A: Bed

The best bed I found on the used market was a 1941 South Bend 9” Model A. It was 48” long. However it came with no headstock, tail stock, carriage and apron, cross-slide or anything else. Just the bare Bed. I like this design, but.. it's 65 years old.

I also found an Atlas 10” Model 10F lathe carriage without the cross slide but it is for a Atlas 10F with flat ways. This brings me to the point where I am wondering how the bed will be constructed.

Thirdly I found an ancient Atlas/Craftsman β€œDunlop” blue model makers lathe in the 109 series. It's very small. Probably 4 or 6” and will only hold up to 12 or 18”.

I was thinking about designing a 13x40 lathe, but found it might be too expensive.

Someone suggested not to use a double V setup. I wanted V's and Flats, or a Flat way. But, the distance between the front and back peak of the V should at least be 4 & ½”.

My bed would be no more than 57” long and no shorter than 28 & ½” long from end to end.

B) Headstock

I need to design and build a headstock that would encapsulate the following:

ABEC 7 Bearings (My choice would be SKF)
At least a 1” Spindle
Spindle length must be at least 12” to 12 & ½” length & No less than 6 & ½”
Have a minimum of 4 pulley steps
Use standard oilers / oil cups and maybe use felt wick
Be able to use #1MT, #2MT and/or #3MT taper shank drills, collets and tooling
The pulleys must use a 3/8” belt
Be made of Cast Iron, Aluminum or Steel.
Use a 16T or 32T stud gear.

C) Tailstock

Has a #1MT, #2MT or #3MT taper
1” dia tailstock spindle with a keyslot on the underside
Uses at least a decent 4” handwheel
uses a tailstock setover screw
Able to be locked down and has a mechanism to lock the handwheel/spindle

Here are my other needs for the project. They are very simple I would bet.. I may have to incorperate these in a larger lathe.

Q/C gearbox
Fit an Aloris AXA or BXA tool post
Taper Turning Attachment
Turret Tailstock
have a 1” lead screw ACME.. and no less than 1/2” made by Rockford Ball Screw
Micrometer Carriage Stop
Micrometer Dials 1” or 2” by .0001” or .001”
Be capable of using Jacobs 14N or a 3/8 or 1/2” ball bearing drill chuck
Threading Dial
Power Feeds on carriage and cross slide
Micrometer Degree scale under Cross Slide (for setting angle of cutting tools)
Be capable of 0.002” through 0.009” feed rate
#1MT, #2MT or #3MT Tailstock Spindle
Decent handwheels around 4”
Have a reliable, sturdy ΒΌ, 3/8, Β½ or 1 HP NEMA Frame motor Single Phase
Be able to hold DRO scales and display
Have a Forward Reverse Off switch and E-Stop
Toolpost Grinder
Be able to use 3C, 3AT or 5C collets
Maybe a D1 type spindle, such as a D1-4
capable of holding and turning 12” long pieces of 4130/4140/4340 steel
. If no Q/C.. be able to use from 2 to 3 or 4 gears on the Gear Banjo
capable of adding a VFD and/or converted to CNC easily
Use gears made by Boston Gear
uses ΒΌβ€œ, 3/8”or ½” square shank indexable insert tooling (positive or negative rake)
Uses readily available standard parts, especially set screws, hex bolts, allen head, or SHCS's
Has a good gib and gib adjustment setup
Has a large spindle through hole
collet closer
uses ER16 or ER32 collets on the spindle nose
uses a good bed leveling and mounting system ; maybe on leveling screws and pads
has a 8” Drive plate / Face plate
uses a 6” 4 jaw chuck with a back plate or a direct spindle mount
easily converted to ball screws and the addition of servos (?)
has a reliable back gear (?)
Uses a steady and/or follow rests
can be adapted to use a 4” chuck or Β½ – 20 tpi threaded tooling
Able to have a Mity Mag set up, Dial indicators and/or a last word indicators
Has a more squarish / rectangle headstock
able to be lubricated with way and gear oil easily
has felt way wipers
ways which are ground and scraped easily
has carriage and cross slide locks
Able to use flood or mist coolant
Collet tray/organizer
Could be made using some THK linear parts

08-28-2006, 02:44 PM
Not to seem like a naysayer, but unless you've already got a lathe, mill, saws, grinders, drill press, etc. etc., the process of constructing a complete lathe from scratch is a monumental proposition.

There's a reason why there are tens of thousands of cast iron behemoths with adjustable gib ways, stepped belt spindle drives, and quick change gearboxes driving leadscrews captured by manually engaged split nuts:

They work, and they've evolved to work that way.

Manufacturing is an unflinching bitch when it comes to maximizing R.O.I., and for machine tool buyers the acid test is whether a major capital outlay will provide a favorable return with regard to productivity and longevity. How does this affect a home shop machinist? with manufacturing in America sadly heading into the toilet there are huge dollar sums worth of assets that are surplus to the needs of their former owners.

Like buying used Mercedes benz cars in urban centers, the prestige is gone after some number of years, but the quality of manufacture is still there.

I'd offer that you could find a nice heavy 10" South Bend or a Clausing 1300 for $2k, maybe a bit more for a nice one with abundant tooling.

It's likely all the tool you'll ever need, it was built to run 2 or 3 shifts a day for years, and you won't need to re-invent the wheel.

Unless of course you *WANT* to re-invent the wheel. In which case I can't wait to see pics of your lathe under power.

And if you're looking to incorporate the best of all lathes in this, make it more like a Hardinge HLV-H.

That's a sassy lathe.

08-28-2006, 06:23 PM
While it is a large undertaking to build your own lathe, it is certainly possible. A few guys around here have built their own machines -- of course many already had lathes and mills. If you haven't got precision equipment to start with, make sure to include plenty of adjustments when you design your lathe so that you can compensate for any errors.

That said, you ought to have a very good reason to build your own. Good quality machines are readily available on the new and used markets -- often at fairly reasonable prices. While they may have some design flaws (new) or minor damage (used), they have still been through enough design revisions to iron out most problems that would otherwise be big headaches in a homemade lathe.

Be careful if you use THK ball slides, as they are way to 'slippery' for manual machines. Friction in conventional slides helps to prevent the cariage from knocking around when cutting.

Do a search of the archives because there are some old posts about homebuilt lathes.

08-28-2006, 11:18 PM
I too have been bitten by the "ideal lathe" bug. I spend hours looking over specs, plans, and old books searching for the solutions of the past, and how I can improve them. I continuely wander the net, auctions, garage sales, etc. to find the bits and pieces that time has orphaned and then struggle to incorporate them in to the next redesign. Making a lathe like object is relatively easy, making an accurate one is a little bit more difficult. My quess is that you have a more than a little bit of know how, but do you have the time (of course money is never important doing something like this) to sink into this (never ending) project?

08-30-2006, 03:57 AM

I've managed to get started on what is going to be a monumental task.
First several details is going to have to be ironed out.

I found very complicated but detailed drawings of the D1 style -4 size spindle. I saved this for my next headstock, possibly on a larger lathe.. if I need something bigger than a 13" lathe. It's a huge .doc text file, a couple .pdf files and several .DXF/.DWG files. all in one .ZIP

Yes, I know I'm re-inventing the wheel for the 10,000'th time.. and I don't have $10-20k to invest in the project, but I think once this has been completed myself or someone could take off with the desgin. However, I wanted to start off where others have left off.

This would be less complicated than designing and building a milling machine that held NMTB 30/40 or CAT45 taper tooling. I think one could better buy a machine of that equiv. for at least $4k. Now, I'd want a CAT45 machine or a NMTB 40 machine cause I have the tooling on hand.

I'd love to have a 5HP inverted vertical spindle shaper/router too but that ain't gonna happen.. basically a huge router and router table desgined to mill/route/shape a periphery on a fixture/jig while guided along a collar affixed around the cutter on the table.

This as well as many other items: 14" metal vertical band saw, 10" metal tablesaw 5/8" arbor, 8"x1" wheeled surface grinder, toolpost grinder, 6"/8" milling vise, 35 ton OBI punch press,

Well, I could go on on about reasons why and why not to build your own lathe but I need one that hasn't been built yet to my knowledge.


08-30-2006, 09:22 PM

I have just seperated from some of my hard earned $$$ for a 3hp overhead pin router, fully functional but missing a few of the accessories to make it fully useful. Another tool to fix, rebuild or design jigs and fixtures for. Have to reassemble my 14" band saw this winter, finish up the 10" table saw, and start the upgrading and rebuild of my 6x48 belt/12" disk sander, and a whole lot of general shop upgrading going on. The mill rebuild is on pause and the metal lathe still needs a bench and some replacement parts. My "let's make a ideal lathe" is still an ever growing pile of "parts and charts"; but one day my widow will have a very well attended auction!

Good luck with your lathe design and build. If what you need doesn't exist than I can't fault you for creating it. Just post us some pictures, if you please.

08-30-2006, 09:38 PM
have a go at the cam lock - I've built a couple (one for indexing head & one for rotary table), not that hard in view of the overall scope of the project and you'll really appreciate the convenience. D1-3 is also big enough that you can still use 5c collets in the spindle (with a 4 1/2 M taper)

btw, what tools do you have to build this with or are you using someone else's shop?