# Metal Lathe

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#### Dan Thomas

##### Well-Known Member
For more than thirty years I used an old Southbend that was still reliable even when we moved and it was sold to make room - a mistake.
Since then I have purchased two different Chinese made lathes, one a Grizzly. These machines use very cheap plastic gears, pathetic belt drives, and components, and you will quickly discover that they are planned to be "absolete" by the distributors in a very short space of time, hence the source of replacement parts quickly dries up and you are forced to buy a new machine. This has happened twice, and I have since sworn off these cheap machines that do not hold tolerance, do not stand up to hard use, and do no have a reliable source of replacement parts.
I spent four years in Taiwan as a flight instructor to the CNAF and have a great respect for the Chinese, but not their "knockoff' mentality and business ethics.

Sonny Furman, Col. USAF ret.
The Taiwanese made much better stuff than the Chinese, but maybe the Chinese will catch up. I used a Southbend in one shop and it was a good little machine, but the headstocks on those used bushings instead of tapered roller bearings, and you'd get chatter with heavier cuts. The Atlas I don't care for; it uses square-section ways instead of the usual triangular self-centering ways, and it develops some slop when the ways wear and you can't adjust it out without it getting tight on the non-worn sections.

I had a Grizzly combination mill/lathe, about 11" swing, in the same shop that had the Southbend. A friend had bought it and had no place for it. The mill was pretty much useless, and the lathe headstock gears would jump out of gear on a moderate cut.

My lathe is a Sharp, built in Taiwan to order by a now-gone Vancouver company, but it uses the same parts as many other models. I haven't had to buy any. The original weaknesses were designed out of it by Sharp, and it works better than any other lathe I've used (about 7 or 8). I bought it from an aloder fellow that had only used it occasionally to machine model airplane engone bits. Never any heavy work. It came with boxes of tooling, too.

#### Dan Thomas

##### Well-Known Member
My shop is 28x24 and I don’t see how in the heck I’d fit all that.

But I have an airplane in mine, plus misc tools and some other storage (lawn tools and crap).
No airplane in my son's shop, just room for a pickup. It is crowded. He manages.

#### ScaleBirdsScott

##### Well-Known Member
I feel like for an airplane the mill easily would be more useful on average. It heavily depends on which design one goes with and what sorts of details it uses. For a lot of parts they are made of thin sheet and it's formed to shape vs hoggin a block to final form as it bypasses a mill and stays light.
In reality a person with enough determination can make most things a mill can using lesser tools. Meanwhile no one is making most of the things you need a lathe for without one of some kind.

So a lathe unlocks potential one doesn't really have otherwise, while a mill opens up a world of possibility that is suddenly viable and lets one do a lot more types of building.

I'd definitely put mill first priority but one without the other is a bit of PB without the J.

#### lakeracer69

##### Well-Known Member
I would say get a mill first, preferably with a DRO ( it takes the ass ache of backlash out of the equation). Accurate hole placement, repeatability, and perpendicularity to the work piece. Quick Jigs and Fixtures for holding parts or things like welding alignment too. Less time making one part equals more time to make more parts, and less trashed parts.

I wouldn't have tried to build a plane if I didn't have one, but that's the machinist in me talking.

#### blane.c

##### Well-Known Member
HBA Supporter
I agree with previous post, having the ability to pass rods thru a hollow headstock is very handy and that the hole will allow at least 1" to pass thru is desirable especially for using 5C collets. Also I like slow turners, I put an vfd controller on my small lathe to get the speed down and my large lathe gears down to 15 rpm. Sure some things will machine best at higher rpms but of course some things are better turned slower such as large diameter objects {because surface speed is rpm x (pie x the diameter)} and also some operations like threading, I like to thread at slow rpm. Finding newer lathes that turn slow enough without modification is challenging, it would be different if they were cnc but manual lathes often need to turn slower than cnc … you know because we are human (I am at least almost human). Fast turning lathes force you to buy carbide cutters because the speed = heat and the heat will roast less expensive high speed steel turning bits. Often slower speeds with high speed steel bits will for the home shop produce better finishes. Also high speed steel bits are easier to grind into custom shapes and to fit into nooks and crannies, but again require lower surface speeds than carbide bits do so often need lower lathe rpms.

BJC

#### blane.c

##### Well-Known Member
HBA Supporter
I would say get a mill first, preferably with a DRO ( it takes the ass ache of backlash out of the equation). Accurate hole placement, repeatability, and perpendicularity to the work piece. Quick Jigs and Fixtures for holding parts or things like welding alignment too. Less time making one part equals more time to make more parts, and less trashed parts.

I wouldn't have tried to build a plane if I didn't have one, but that's the machinist in me talking.
Yes, probably the first machine tool needed is a drill press and since a mill can do most anything a drill press can and more and with better accuracy it makes sense.
…. well that and a bandsaw, much time is saved with a bandsaw in machine work … but I digress.

#### Aviacs

##### Well-Known Member
The Atlas I don't care for; it uses square-section ways instead of the usual triangular self-centering ways, and it develops some slop when the ways wear and you can't adjust it out without it getting tight on the non-worn sections.
The worst thing about Atlas's is they use the leadscrew for feeds. So they wear out, quickly, up near the headstock end. Making them unreliable for threading, and eventually poor surface for feeding. (Real metal lathes separate feeds, for general turning or facing; from threading, preserving the master thread leadscrew & half-nuts for that purpose only. Feeds are usually through a gear train and rack drive under the front way of the lathe). Besides that, the larger (12"? We have one in the group hangar, but i only set it up and mostly ignore it unless a member asks for support) are fairly competent. They do have zamac gears, which are weak, and deteriorate even without use in some cases due to the alloy used. The 6" machines have spindles so small they bend, and also have a poor chuck register that tends to take poor, purpose made chucks, IIRC. However, Atlas are reputed to have been the most widely produced metal lathe in history. Some of the Chinese clones may have overtaken them by now? Find a project, even some very complex things, and someone somewhere has probably built it in a home shop on an Atlas.

My lathe is a Sharp, built in Taiwan to order by a now-gone Vancouver company, but it uses the same parts as many other models. I haven't had to buy any. The original weaknesses were designed out of it by Sharp, and it works better than any other lathe I've used (about 7 or 8). I bought it from an aloder fellow that had only used it occasionally to machine model airplane engone bits. Never any heavy work. It came with boxes of tooling, too.
Sharp is generally perceived as a very reputable make, they cloned copies of most of the Hardinge lathes and tooling, and are more or less considered comparable. Their electronic threading is arguably superior or at least more versatile. For a while, before the Hardinge factory auction here a few years ago, they even had some Sharp machines for study purposes. That said, i own & use some old Hardinges but never personally ran a Sharp.

smt

#### blane.c

##### Well-Known Member
HBA Supporter
I haven't any experience with Logan lathes but they are reputable and Logan still sells some parts for them which is the main reason I mention. http://store.lathe.com/

#### Aviacs

##### Well-Known Member
Logans are essentially South Bend clones....except with ball bearing spindles.
People can (& have) argue for a week as to whether it makes a difference in this class of lathe.
My perception of the smaller Logans is also that some of the castings might appear a tiny bit heavier than SB.

#### Dana

##### Super Moderator
Staff member
The thing with the mill is you end up using for a lot of things that become easy, just because you can. Like my Starduster landing gear... cutting the brake mounting disks on the rotary table and drilling the holes precisely, a no brainer, but then freehand cutting the tubing fishmouths and only needing to touch them up with a hand grinder. Or the time a new oil pump for my Jeep didn't quite clear a main bearing cap, it was a simple matter to clamp it in the mill and take 1/16" off one side. I could have done it with a bench grinder, but it would have taken a lot longer and resulted in a much rougher cut.

My Jet mill is an older Taiwan one and "OK" if not great, by all accounts the newer mainland China ones are a lot worse. I converted it to a variable speed DC drive (treadmill motor/controller) which saves a lot of belt changes.

The Atlas lathes were a not-insignificant part of WWII production; a lot of people had them in their garages making small parts for the war effort as a part time gig.

##### Well-Known Member
Cheap Engine hoists are good for 2 ton. Add a shed with a flat floor, and anything under 2 ton is reasonably portable.

##### Well-Known Member
I used my mill more than my lathe for airplane parts when I had both.

A small bandsaw, grinder, drill press, and combo disc/belt sander will support the typical build in my opinion. Of course you can never have too many tools!

Craigslist is a great place to source a mill and a lathe. I purchased my lathe for $500 with a ton of tooling and my X3 with an upgraded motor (no tooling) for$1500 back in 2012.

#### Lendo

##### Well-Known Member
I can't live without my Lathe, I bought a Chinese one some years ago - It's good enough (1 Meter Bed with metal gears). I had never used a Lathe until I purchased this one, I would like a better, more accurate one, but can't justify the outlay.
I do believe the Taiwan Lathes are better value if a little dearer.
George

#### Armilite

##### Well-Known Member
Hi all,
Been thinking about picking up a bench top metal lathe, but I do not want anything huge. I really need to be able to put in the bed of a truck and be able to move it fairly easily. What is the minimum size that might be useful for run of the mill airplane construction? I can't image that I would ever need anything larger then 8x16, but a small 7x would be so much more convenient. And no. There is zero chance that I am ever going to get a giant South Bend. Its bench top or nothing.
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I have had a 12" x 37" lathe for probably 25+ Years and a Large Bench Mill. I don't think I have ever turned anything Larger than 8" OD and probably 22-24" Long. The nice thing is I can turn something bigger if needed. So Minimum I would want for a Small Lathe is 9" x 20". Mini Lathes are ok for Plastics and Aluminum and Steel, etc., you just have to use Good Tooling and take much thinner Cuts, which means more TIME. Today, there is even Mini CNC Lathes & Mills & Routers & Lasers, & Etchers, & 3D Printers.

There is a lot of Good Industrial CNC Mills and Lathes out there on Graigslist and Face Book Market Place. You can make a Trailer for just about any machine if you want it Mobile.

Try Little machineshop.
https://littlemachineshop.com/products/products.php

Grizzly Tools.
https://www.grizzly.com/lathes

Emco Compact 5 CNC Lathe $2,500 This CNC Mill is 4000 lbs, has a 10 Tool ATC, he's asking$1,200.

#### BoKu

##### Pundit
HBA Supporter
I have the Chinese 9x20 sold by Enco, Grizzly, and formerly by Harbor Freight. When I bought it with a friend about 15 years ago I wondered if we would ever really put it to use, but rarely does a week go by that I don't do something or other on it.

One important thing to understand is that the precision that is conveniently available is proportional to the mass of the machine. The heavier the headstock, bed, and carriage, the stiffer they are and the closer the tolerances they can hold. You can pretty much get down to 0.0005" with any machine, but the lighter the machine the more time you spend measuring and tuning between cuts. "Sweating out parts," as my retired machinist father-in-law says.

Another thing I learned from my father-in-law, the best setup machinist I've ever worked with, is that consistency of process is the key to consistency of results. For example, when turning a certain bushing, I'd do three 0.030" axial cuts in quick succession, then do a 0.010" cut, then go to my 0 mark for a final 0.002" cleanup pass. Repeating that exact sequence of cuts in brass or porous bronze I could pretty easily get a 0.001" +/- 0.0005" press fit in all of a batch of 20 parts. Of course, with a big engine or even toolroom lathe I could probably churn them out in two cuts each, but I don't see a machine like that amortizing itself in my shop.

--Bob K.

#### blane.c

##### Well-Known Member
HBA Supporter
Sometimes making thicker cuts doesn't save time because it increases the heat in the parent material making it a sconce larger in dia. , then you have to wait for it to cool down in order to make a finishing cut.

#### BBerson

##### Well-Known Member
HBA Supporter
My dad ran a big lathe at Continental Motors. He taught me that for the finish cuts take half off each cut.
So, if it looks like a .004" cut would be correct, instead take only .002". Then measure and if it now looks like .002" cut is needed take .001". Then .0005 etc. This will give a nice finish with the last cut taking almost nothing.

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#### Turd Ferguson

##### Well-Known Member
Sometimes making thicker cuts doesn't save time because it increases the heat in the parent material making it a sconce larger in dia. , then you have to wait for it to cool down in order to make a finishing cut.
That's why they make coolant.

#### stanislavz

##### Well-Known Member
HBA Supporter
Mine history. Firs lathe, was an sieg sc4. 8x20 size. Ok for 95% of work for plastic aluminium. For steel - only sharp tools and low pasess. And one of mini mill. Just horrible.

Next was A Sir. From uk, harrison vertical mill. And an harrison vs330 lathe. Same as m300, just cvt in place of gear box.

Mill was close to new condition, lathe need some regrind.

But now - i do not care. Steel or plastic. 0.02mm/0.0001" is doable with any head scratching. Surface finish always nice.

Mill is a dream on itself.

Just your are doing same operations much faster and no waste. Funny part - due to being three phase, they was close in price to chiness "**itty" tools.

#### blane.c

##### Well-Known Member
HBA Supporter
Just a 3 phase converter or change out motor to 220 (in USA) I've done both, which are fine if you don't need variable speeds. VFD is best with 3 phase motor then most any rpm you want.

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