Lathe – Getting Started

Posted: 17th January 2017 by Quinn Dunki in Hacks

From a dream to first chips

 

If you’re interested in making things, and particularly metal things, you’re on a road that eventually leads to machine tools. Machine tools have a special place in history, because they are basically the difference between subsistence farming and modern civilization. A bold statement, I realize, but the ability to make very precise things is what gave us the industrial revolution, and everything that snowballed afterward. If you want to build a modern life filled with jet airplanes and inexpensive chocolate, start here.

I have recently arrived at the “I need machine tools” stop on the road, and it’s a place I expect I will hang out for a while. When I was getting interested in the topic, however, I couldn’t find any good references for absolute beginners. I hope to write a series of blog posts here to plug that hole in the internet. I am not an experienced machinist, but I hope that will work to our advantage for these posts. Very experienced folks often forget how little a beginner knows, and machining is an enormous and bewildering topic. There’s a reason people spend their entire lives getting good at it. It’s a huge base of knowledge and skill to dip your toe into. That said, this series will not really be a machining lesson (see below for resources on that). This is intended to be more like a roadmap for how to get involved in this hobby.

A quick word on safety is in order before we proceed. Lots of things in the shop can be a bit dangerous, but machine tools are unique in that they are actively trying to murder you at all times. Always wear safety glasses, and never have long sleeves, long hair, or gloves. These machines are powerful and will hurt you badly before you know what has happened. Respect the lathe. Always be thinking about that spinning chuck and what a strong taste for human meat it has.

Let’s start very conceptually. What makes something a machine tool? A good working definition would be a machine that cuts metal with high precision in a very repeatable way. The word “cuts” is the key there. Unlike stone-based tools such as grinders (which make dust), a machine tool removes shavings from metal stock with a cutting edge made of a harder metal. It’s just like shaving cheese with a grater, but several times more bad-ass. You cut mild steel with tool steel, tool steel with tungsten carbide, and tungsten carbide with space lasers. Portions of that sentence were fictional, but you get the idea.

The universally agreed-upon place to start with machine tools is the mighty lathe. It was the very first one, and you can’t build most things without it. People like to say that the lathe is the only machine tool that can make itself. I suppose that’s true in some very particular sense, but it’s a bit disingenuous. It would be more accurate to say that no machine tool can be made without a lathe. If you’ve read the Gingery lathe series, you know that a hand-scraper and a reference surface is what makes most of a lathe, but you certainly need the lathe you are building to make many of its own parts. It gets pretty lathe-ception, but you should read the Gingery books if you’re interested in that.

At this point, you might be thinking, “that’s all great in the abstract, but what am I going to make with a lathe? What’s the point of owning one?”. Well, these things are called “machine tools” for a reason. They are tools for making machines. Anything with moving parts will need a component made by a lathe somewhere in it. You might want to make model steam engines, RC car parts, clocks, or wind chimes. You might be restoring an old car, designing custom bicycles, making metal furniture, or building robots. Just about any object involving moving or round parts probably involved a lathe in its production. Making that mental leap from what a lathe does to how you might personally use it is one of the objectives of this blog series.

As a starting point, you can try looking around you at the metal parts in your world. If it’s something round, or especially if it’s something that moves, odds are a lathe was involved. You can look closely at the surface of the part (assuming it isn’t painted). If you see what looks very fine stratification in the surface, those are machine tool marks. The more professionally done the part is, the smaller these marks will be. Of course, nowadays many things are also made with cheaper processes, such as sintering or precision casting. When it really matters, though, there’s still no substitute for machining.

 

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This is a bearing cone from a quality Shimano bicycle hub, photographed with a strong macro lens to show the surface finish. See the horizontal tooling marks? This was machined on a lathe.

 

My goal in this first post is to walk you through every step from “I want a lathe” to hitting yourself in the face with hot chips (not recommended, but let’s face it- it’s going to happen).

Sooner or later, you will need to some basic education on lathe operation and machining. Here are some starting points that I recommend:

  1. Tubalcain’s YouTube channel. Tubalcain (aka MrPete) is the internet’s shop teacher. His “How to run a Southbend lathe” series is an excellent resource for operational basics of these machines, and binge watching his entire channel is time well spent. If you want to get a nice organized video course on the lathe, he sells that here.
  2. Machining Fundamentals. If you’re like me, you like to do some hardcore research on any new hobby. For that, I recommend this textbook. It’s not as hands-on useful as Tubalcain’s videos, but it will give you a basis in machining vocabulary, reading engineering plans, basic metallurgy, the physics of how machining works, and so on.
  3. Metal Lathe. I include this with some caveats. It’s often recommended as the place to start, because it is project-based. However, I found this book assumes a fair bit of knowledge and ownership of other machine shop equipment. The very first project in the book turns out to be quite difficult for a true beginner, and I didn’t find it to be the best place to start. One of my goals for these blog posts is to build you up to the point where this book starts, and to save you some of my missteps.

 

Okay, enough reading. Time to spend some money!

The obvious first question is- which lathe to buy? This is a doozy of course, but it largely comes down to what you want to make and how much space you have. The traditional wisdom says to buy the biggest machine you can, because you can make small parts on a big lathe, but you can’t make big parts on a small lathe. This is true to a point, but if your goal is clock-making, I wouldn’t buy the 20″ engine lathe that you found on craigslist. A machine roughly suited in size to the task at hand will make life easier. That said, try and buy a bigger machine than you think you need, because larger machines are more precise, easier to get good results with, and more versatile.

A quick sidebar on units- I’m going to be using Imperial (aka SAE) units here- inches. That will no doubt enrage readers outside North America. Don’t get me wrong, I love metric stuff. However, in America, all the metal stock, hardware, plans, etc, are in Imperial units. Using metric in this environment is swimming upstream. Truth be told, I find Imperial units to be easier for machining, because you’re doing everything in a single flat integer number space: thousandths (aka “mils”). With metric, you’re dealing with fractions of a millimeter all the time, and that’s much more annoying to my primitive brain. In any case, a good machine tool sold in North America will do both, so pick your poison.

Lathes are measured primarily by “swing”, which is the size of material that you can swing around in the chuck without it destroying the furniture. Typical floor-standing lathes are 10″ and up. Typical bench-top lathes are 9″ and smaller. They are also measured by “distance between centers”. This is the longest piece of material you can turn. For the average hobbyist wanting to make gadget-scale machine parts, steam engine models, etc, something in the 9″x 20″ range is a good place to start (9″ swing, 20″ between centers).

The second major question for any machine tool purchase is: Do you buy used American stuff, or new Asian-made stuff? Old American iron is generally considered to be better made and more precise. The modern Asian tools aimed at hobbyists, however, will be brand-new and ready to use. Beautiful pre-1980s American machines can be found on craigslist and such, but probably need work to get them in good shape again. You are likely buying a project. Furthermore, if you want a smaller bench-top machine, Asian is the way to go, because the older American machines are, as a rule, large. These newfangled Asian machines can also do some neat electronic tricks that the old stuff can’t, as we’ll see in a bit.

For me, power cross-feed was something I really wanted. Pretty much all lathes have power feed on the main axis, because that’s the secret sauce that makes cutting threads possible. The motion of the cutting can be synchronized with the turning. Power feed also serves to make nice surface finishes and saves you effort when a lot of material needs removing. The same is true of cross-feeding, so I wanted power-feed on both axes.

At small bench-top machine sizes, power cross-feed is uncommon. There’s pretty much two choices- the variants of the Sieg SC4, and the Precision Matthews line. My favorite of the former is the 8.5×20 HiTorque from Little Machine Shop. It’s a great machine that I came very very close to buying. In the end, I opted for the Precision Matthews PM1022V. It is slightly larger and comes with a great selection of accessories. The PM folks were terrific to deal with, and the machine was well shipped.

The next question is what tools and accessories you might need. The rule of thumb is that you will spend at least the cost of the lathe again on other related fiddly bits. This is true enough, however this money can be spent gradually over time. To get started, the bare minimum I would suggest is:

  1. Way oil for lubricating the machine. “Way oil” is basically any ISO 68 grade oil. There are lots of names for it, but if it says ISO 68, you’re good. You can buy it locally at machine shop suppliers, or online.
  2. Cutting fluid for cooling your cuts. Something like Tap Magic works well.
  3. Mechanical Caliper. You need to be able to measure diameters and depths precisely, and a caliper is also handy for scribing lines. Get a decent mechanical dial caliper. Those ubiquitous digital ones go through batteries like a new parent goes through booze. Eventually you will need a micrometer set, but a quality caliper is sufficient for the levels of precision that a beginner can achieve.
  4. Drills. Really high quality drills are worth every penny, and can be resharpened for a lifetime. Cheap drills are more annoying than a radio announcer chewing gum. Splurge and get a nice full index like this great set from Little Machine Shop. You will not be sorry. Make sure to get a set of center drills as well.
  5. Jacob’s chuck. You need to be able to mount drills in your tail stock, and this is how you do it. Make sure the chuck you buy includes the right morse taper for your lathe. It’s likely MT2 or MT1 for small bench-tops.
  6. Quick-change tool post. I’m going to go ahead and call this a requirement, because the improvement in workflow is tremendous. It will save you a lot of grief and learning curve, because you can set tool heights precisely and repeatably with minimal effort. Whoever sells your lathe will offer this as an option. Take it.
  7. Stock! It’s easy to forget, but you need metal to work on! Go to your local supplier and get some round bar in varying dimensions from 1/4″ to 2″ or so. I strongly recommend getting 12L14 free-machining steel. This is a high-lead-content steel that machines really nicely, and will help you have a good first experience. If you buy who-knows-what alloy from the off-cuts area, you may have a bad time indeed.
  8. Tool bits. Here’s where I’m going to get crap from the curmudgeons. I recommend buying one set of pre-ground High Speed Steel tool bits, such as these for 3/8″ or these for 1/4″ bits. Yes, these pre-ground sets are way overpriced and they are preying on beginners. However, this saves you the learning curve of grinding bits until you are comfortable with how a lathe works. This is the best advice that nobody gave me, and it’s my gift to you. Also, avoid the siren song of carbide insert tooling. It looks like a way to bypass the traditional HSS skill set, but it isn’t, really. Carbide inserts need high speeds and feeds to work properly, and there are minimums below-which they don’t cut properly at all. As you can see here, surface speeds for carbide are 2-3 times higher than HSS. A typical hobby machine doesn’t have the horsepower to turn material at the RPMs needed, nor the torque for the depths of cut needed to get good results with carbide.  You will also need HSS sooner or later for more creative and interesting cuts, so get comfortable with it now.

 

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Here is the overpriced-but-learning-curve-shrinking Grizzly tool bit set. Left-to-right, they are: Boring, thread-cutting, offset thread-cutting, turning/facing, turning/facing (again), parting, right-offset turning and left-offset turning. The turning tools provided in this set have sharp points on the end. Round them over a bit with sandpaper or a 120-grit grinding wheel to get much better surface finishes on your parts.

 

That’s enough to get started. You’ll acquire a lot more tools and accessories as time goes on, but you can make some fun stuff with little more than that. The financial pain of tooling can be lessened by buying stuff gradually as you need it. You can pick up random lots of stuff on craigslist, eBay, or local machine shop auctions. Quality tools can be refurbished almost indefinitely, so don’t be afraid to buy old stuff if you’re willing to put in elbow grease to clean it up.

So, you’ve pulled the trigger, your credit card is steaming, and the machine is en-route to your home. Now what? First of all, I hope you have a place to put it. Machine tools are, of course, all about precision. Precision is all about rigidity. Rigidity is all about mass. Thus for a bench-top machine, the more massive a bench you can bolt it to, the better. If the bench shifts, warps, or becomes unlevel over time, the machine tools sitting on it will become less and less precise. Precision is the game, and mass is the way you play it. In my case, I opted to build a really silly steel bench, but do whatever works for you. It’s also worth double-checking your electrical. While these smaller machines are mostly plug-in 110V (for North America), they do sometimes require a 20A circuit. You may only have 15A circuits, as is typical in older North American homes.

Speaking of electricity, these bench-top Asian lathes have some neat tricks that old American iron can’t perform. They often use an electronically controlled brushless DC motor, instead of AC. This means you can change (and even reverse!) the spindle speed with the turn of a knob- no gears, no belts. You don’t even have to shut the machine off. That’s a really really nice feature, especially when you’re learning about feeds and speeds. Being able to easily experiment with spindle speed shortens the learning curve of lathe turning considerably. On some machines, you can even reset a threading pass without losing your place on the threading dial, simply by reversing the motor instantly.

Okay, the big truck came and went, and our machine is here! All the best things in life arrive on a pallet, and a lathe is no different. Make sure you budget time to set up the machine. If your shop is your garage, you may not get the car(s) back in for a couple of days while you’re getting everything going. It takes time to get the crate open, separate the machine from the pallet, prepare the bench area, hoist the machine into place, and so on.

 

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What’s in the box? It could be anything! Well, I guess you know by now it’s a lathe. Still, try to act surprised when I open it, just to be polite.

 

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Underneath the drip tray, we see the machine itself. Unfortunately, this was bolted to the pallet crooked, and as a result the sheet metal splash guard on the back is a bit bent. Not a huge deal. Things shipped by freight pretty much always get a little damaged. That’s just life.

 

I ordered the quick-change tool post (as previously recommended), and they installed it for me. That was a very nice surprise.

The Precision Matthews machine comes with a lot of accessories, which I really appreciate. These are all carefully stacked in the crate with the machine.

 

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Left to right, we have two steady rests, a faceplate, a toolbox with all the wrenches, extra gears, etc that you might need, a four-jaw chuck, touch-up paint, and the quick-change tool post. Since they installed that for me, the box contains the original four-way tool post, and all the extra quick-change holders that came with it (two for normal tools, cut-off blade, boring bar, and knurling tool). Also visible is the instruction manual, which is well-written and quite helpful.

 

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The one disappointment in the included accessories is this oil can. It’s of very poor quality, and has leaked more oil all over my bench than it has ever applied to a machine. Its inclusion in the package is a nice thought from Precision Matthews, but I would have happily paid a few dollars more for one that wasn’t terrible. I immediately replaced this with a nice Goldenrod can.

 

After carefully removing the crate from around the machine, the next step is to prepare your bench. The drip tray acts as a handy drilling pattern for the mounting holes in the lathe’s feet.

 

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The nice thing about a steel bench is that you can just drill holes anywhere, and whatever you mount there will be bulletproof.

 

Now the moment of truth- lifting the machine into place! The PM1022V is relatively light as machine tools go, weighing in at 360lbs. A group of strong folks could lift it by hand, or use a shop crane as I am doing here. Make sure to consult with your manual on the proper lifting points. Usually, “straps around the ways” is the correct method, but check your manual to be sure. Also make sure your straps aren’t going to pull on the lead screw, or anything that isn’t a casting. Take your time to find the balance point. Lifting a machine like this is a lot less exciting if it is well balanced, and lowering excitement is the goal when you have thousands of dollars hanging four feet in the air.

 

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Here we go! I did some small test lifts to find the center of gravity, then lifted and swung the crane gently over the bench.

 

 

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Hooray! The machine is on the bench. You might have noticed I forgot to put the drip tray in place. The truth is, I forgot to drill the holes too. That’s why, in the hole-drilling photo you saw earlier, the lathe is actually sitting at the other end of the bench. The safest thing to do was gently crane it over a little bit rather than putting it back on the floor. Plan ahead better than I did so you only have to lift the machine once.

 

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Next, unpack all your goodies, and refer to the manual.

 

The manual will have a first startup and break-in procedure. Make sure you check the oil in the head. Some manufacturers fill it for you, and some don’t.

 

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This is a good time to pop the cover off the gear train and inspect it. Some grease on these gears is recommended by the manual. The machine comes with a second set of gears for a higher set of speeds, but I haven’t found them to be necessary yet.

 

You’ll want to clean up all the unpainted surfaces with some brake cleaner to get rid of any cosmoline (packing grease). Then wipe everything with way oil to lubricate and protect it.

 

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You’ll also want to do a pass on all the lubrication points with an oil can. These ball fittings enable you to inject oil into places that wouldn’t be reachable, such as the cross-slide lead screw.

 

It’s also important to make sure your machine is level along its entire length. If part of the lathe isn’t level, it will cut tapers because the bed is slightly twisted. You can level it by shimming the machine, or using adjusting feet on the bench. In the pictures below, I’m using a bubble level. Really, you’re supposed to do this with a properly calibrated machinist’s level, but for our rookie purposes, this suffices for now.

 

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Check for level in a few spots along the ways.

 

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It’s also worth checking surfaces like the top of the carriage, just to be sure things are aligned and properly assembled.

 

Okay, the machine is bolted down, cleaned up, lubricated, leveled, and you’ve followed all the pre-startup instructions in the manual. Time to turn it on for the first time! This is pretty exciting.

 

 

You can see the digital speed control in action there, and it’s pretty sweet. You’ll also notice there’s a large interlocked safety guard over the chuck. I normally take guards like that with a grain of salt, and often defeat them because they are more trouble than they are worth. However, I have been surprised to find this guard is not in the way at all, and it even protected me from shrapnel once when a cut-off blade exploded in the tool post (as they have an annoying tendency to do). I’m leaving it in place for now, but it would be easy to remove if you so desire.

There’s one other thing worth checking with these DC lathes- the tachometer. Mine didn’t seem to read correctly for what the rating of the machine is supposed to be, so I checked with a hand-held digital tachometer. Sure enough, the built-in tach has a lot of error in it for some reason. I don’t know if mine is faulty or if this is typical, but it’s worth doing a bit of calibration rather than trusting the numbers implicitly.

 

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As you can see, the error on the built-in tach is quite large. It’s a mystery, but I’ve learned to mentally adjust for it.

 

Okay, I promised chips, so let’s make chips! This might sound like an anticlimax, but I think the best way to make your first chips is by center-drilling some stock. This is something you will do many many times, so it’s a good thing to get comfortable with. I should preface this by saying you would normally face a piece of stock before center-drilling it. However, we’re just trying to get our feet wet here, not make something precise.

Slap your Jacob’s chuck in the tailstock, chuck a center drill, set your RPM to around 500, apply some cutting fluid to the drill, and ease it into the work until it is 2/3rds of the way up the angled portion. Congrats! You’re a lathe user.

 

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First chips! Upon this altar we shall build a civilization.

 

Okay, that’s where we’ll leave it for now. The next installment will involve actually making something! Let me know in the comments if this series is something you’d like to see more of, or if I should just go back to building computers and outsmarting cats.