Conventional wisdom dictates that the lathe is the ultimate machine tool and the only machine that can reproduce itself. While we wouldn’t argue with the lathe’s primacy in the machine shop, this DIY heavy-duty lathe pretty much disproves that last statement.
Sure, we’re all used to seeing homemade lathes, and we’ve looked at quite a few of them. But two things make [Jornt’s] build stand out: the few specialized tools needed to build it, and the sheer weight of the finished product. While most homemade lathes tend to be benchtop lathes and feature cast aluminum components, [Jornt] uses a lot of steel. The base and bed of the machine are welded together from scrap I-beams, and the guides are made from angle iron ground with clever jigs to hold the angle grinder in place. Angle grinders play an important role in the manufacturing process, as do simple tools like hand drills, files, and welders, and yes, there’s also an unfinished lathe used to bore out the bearing seats for the headstock.
The entire lathe is driven by a treadmill motor and weighs a whopping 450kg, an approach to drive that [Jeremy Fielding] would probably approve of. It looks like something you could buy from a catalogue and has the functionality of most commercial machines. One thing we would have liked to have seen on this machine is an electronically controlled lead screw, which [James Clough] developed for his standard lathe.
It weighs over 1000 pounds and is not really heavy metal. The position of the machinist on the carriage is as follows:
https://i1.wp.com/makezine.com/wp-content/uploads/2011/11/enormous-lathe-614×443.jpg?resize=614%2C443&ssl=1
I used to work for a company that made grinding machines for production lines. The bed is made from a single cast steel, weighs several tons, and is annealed for months. On oil drilling components weighing hundreds of pounds, the grinding accuracy is down to 0.0000001 (millionths) of an inch. Making a chuck of a hundred pounds of parts was a major engineering challenge in itself. We needed special equipment to lift and transport the bed, which was too heavy for standard forklifts and cranes. Each batch is loaded into an “oversized” truck equipped with a guide rail and lots of flashing lights.
I am curious about the repetitive preservation of the prism guides. Many lathes have flat guides, where the front edge of the flat guide is used as a guide for the carriage. This greatly simplifies the manufacturing process, especially if you decide to use a precision ground flat plate as a bed guide for the carriage to move. After heavy use, the front edge can wear out, which means you will have to tighten the carriage wedges (due to uneven wear, this means you will have to adjust the wedges so that they work outside the worn area). However, if you use a 20 mm thick steel block, the wear zone is larger than the prism guide, so its service life should be longer than the prism guide. In addition, it has the great advantage that regrinding the bed is easy and only requires one setup on the grinder to machine the top, front and back edges of the guides (where the wedges bear the load). Plus, if you’re that kind of person, it’s a lot easier to shave. So what’s the appeal of prismatic rails? (I mean, this is partly biased because my lathe is flat bed and it works fine.)
For a vertical support edge, something is needed to pull the carriage up to the support edge. For prismatic carriages, gravity does this.
Now, I don’t know anything about lathes other than how to turn a very rough prototype on a lathe, but to me that’s the most obvious advantage of the prism approach.
Several toolmakers I know use precision lathes and Hardinge HLVH flat slides. If this machine worked for them, I’m sure I wouldn’t have any problems.
Yes, they were wonderful – when I was there, there were three such machines in the machine shop of our faculty.
This is the most impressive DIY lathe I have ever seen. It is obvious that a lot of thought went into the design.
However, I was disappointed that there was no precision in the alignment of the spindle and tailstock with the ways. The same goes for the alignment of the front and rear ways. I suspect that the machine is not that precise. The wobble of the drill when drilling with the tailstock indicates a significant misalignment of the spindle and tailstock axes. When the workpiece rotates, the drill *always* follows the axis of rotation. Therefore, the tailstock and drill head will wobble.
However, a good machine can do quality work on a completely worn out machine. It’s just slow and requires a lot of measuring and adjustments to make accurate parts.
For this design, the best way to drill the headstock is to install the front and rear support plates, install temporary drill rods on the cross slides and carefully align them parallel to the rails. Then feed the rotating drill rod into the workpiece to drill the holes. This ensures that they are aligned and parallel to the rails. Then drill the hole in the tailstock using the same settings. (See David Gingery’s book for more details.)
A weld like this will move like crazy over time. It’s a really good idea to build a heat shield, light a big fire under the lathe, and anneal it before drilling the spindle and tailstock.
The great thing about the Gingery design is that you don’t have to align the temporary headstock perfectly with the bed. As the headstock rotates, you move the carriage along the bed, causing the headstock to become parallel to the bed. Then you use the main headstock to bore into the tailstock, moving the tailstock along the bed again until it is again very parallel to the bed.
If you really want to know why a [well-made] prismatic lathe is slightly more accurate than a straight one, read the book “Fundamentals of Mechanical Accuracy”. In some countries (continental Europe) the standard design for lathes is to use prismatic ways, whereas in the UK the standard design is to use a flat bed with a leading edge.
I agree with this suggestion. Although there is a PDF version available, you can still buy the book directly from Moore (it’s phenomenal).
This book is a must read for anyone serious about building real machines. I have a copy on my bookshelf. Hole Profiles and Surfaces is also a good introductory book that will take you into more detailed information.
However, this seems like a very simple Arduino project. If I had to make it, I think I’d use a decimal switch to toggle the tone. Just because I like them 
Well said. I don’t understand why this Clough ELS is mentioned, it’s too limited in functionality and poorly written. The veteran Artisan ELS is already way ahead, even with its limitations in synchronizing stepper motors with the spindle.
The design is great, but you don’t want to lean over and look directly at what you’re cutting with an angle grinder. I wouldn’t even criticize the fatal pitfalls of the “angle grinder table saw.”
The cost/benefit ratio for this project was a bit low, and the lathe ended up not being very good. Welded steel without heat treatment tends to warp over time, and the carriage doesn’t match up very well with the bed, as you can see from the wear marks on the bed slides at the end of the video. It’s also pretty much a “standard lathe”. By designing the carriage a bit differently, you can already get a good XY table as a starting point for a milling machine.
First of all, it takes twice as much effort to put something like this together with basic tools. It is, after all, a working lathe. I really like the “double half nut” hinge. Simple but effective. I prefer the actual tool sounds to the “music” in some of the other videos. I had to turn those sounds off.
Some ideas you might want to consider: Attach sandpaper to the bed and rock the carriage over it. This is an easy way to improve the fit and will reduce wear over time as the bearing surface area increases. (Cleaning this thing isn’t worth the effort due to welding and warping issues.)
Mild steel on mild steel does not have good wear resistance. A simple way to solve this problem is to glue brass strips (Loctite or epoxy) to the bolt. Or use hardened steel, such as a steel ruler (stainless steel), placed on the frame or under the carriage.
If you do a lot of taper work, make an adapter that works with a cordless drill for the side guides, just like you did when you first built the lathe.
I was also very surprised by the design (and drawings) of the Crosskart/Dune Buggy. https://www.youtube.com/watch?v=UNtU9cK6ONU
I agree with this – for most people the cost/benefit is pretty small, we live in an age of abundance and for most people buying a new imported lathe or a used lathe is probably cheaper than buying the raw materials and parts. It is cheaper to make lathes.
Even starting with a very poor unit, repairing/improving its flaws/wear/damage will likely result in an improved final product, as even the finish may be poor and parts like bearings and screws may need to be replaced with higher quality parts, at least the important major components are solid castings.
I think it depends on whether the goal is to own a lathe or learn how to build one, both are valid.
I saw similar comments below but didn’t get the point. I’m obviously not very good at searching as I couldn’t find any additional information.
Can anyone explain why this is happening? Or what is the name of this phenomenon so I can look it up? I understand that the weld will bend/shift immediately during cooling due to differential heating/expansion during the welding process, but I don’t understand why this would cause the object to bend further in the long run.
Impressive construction, I love DIY projects like this but one thing is overlooked… steel is terrible as a load bearing surface compared to steel… bite etc… last year I used cast iron and bronze for a shiny sliding surface The steel rails were CNC machined… the shiny steel rails were relatively straight and bolted on… no welding due to warping… the tops were hand finished with surface panels and glued on with sandpaper… a year later the tops are working fine…
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Post time: Dec-05-2024
