It’s widely understood that machine tools, or heavy equipment in general pose inherent risks to the operator on a day to day basis. The metal lathe is no exception to this and is tremendously dangerous. With enough training and necessary precaution, the majority of possible injuries can be avoided almost entirely. A general rule of thumb, no pun intended, is that the machine does not care, about your thumbs or any other body parts. Whether the machinery is a fork lift, heavy hydraulic equipment such as excavators or dump trucks, to machine shop equipment and high horsepower electric motors. Imminent danger is often present. Unfortunately, many people have been seriously disfigured or killed in the manufacturing industry over the course of 200 years. It is very important to understand the dangers of the lathe, why it is the most dangerous machine in the shop, and realizing that complacency is the enemy when operating such equipment.
Brief History on the Lathe
The lathe is a tool that dates back many centuries, even far beyond the scope of the industrial revolution. It is utilized in the manufacturing of round, cylindrical workpieces primarily in the metal working or engineering industry, as well as other hobbyist type lathes for wood working or small home shop set ups. There are even miniature lathes for watch making that span all of about one foot in length. This study will mostly tailor towards full size engine lathes, also commonly referred to as manual lathes, chuckers, jobbers, basically any type of lathe that is mostly open body and manually operated with hand wheels and auto feeds and gearboxes. While CNC lathes offer their own array of risks and dangers, starting off on the basics will translate easily to understanding CNC hazards later on.
It is a surprisingly ancient tool. The ancient Egyptians were able to utilize this technology as far back as 1300 BC, most likely for the procurement of round pillar structures made of stone or wood. Being able to turn a tree trunk into a somewhat perfect cylinder would allow, for instance, rolling movement of heavy objects by means of moving one of several wooden dowels from the back of the row to the front, acting as rigging. This technology would have significantly improved the timeline for building the pyramids, which took place 1500 years earlier in 2780 BC. A lathe from Before Christ would most certainly be powered by man or horse, either a foot pedal like a sewing machine or just simply worked by hand. In fact, The lathe is known as being the one tool that invented everything else. It is unclear who invented the first modern era lathe. This technology could introduce some new hazards to humanity but, buy and large, most of these crude contraptions would not be particularly dangerous, being man powered. It is widely believed Leonardo Da Vinci invented one of these prototype lathes most likely sometime in the early 1500s. It wasn’t until 1718 Anno Domini that Russian engineer Andrey Nartov invented the first known metal cutting lathes with a carraige and gears. It is hard to verify if any true images of this lathe exist. It too was most likely powered by man as this was still way before widespread use of line shafts.
Not even half a century later, Jacques de Vaucanson (VOH-cun-so) in 1751 or possibly also 1760, invented what is considered as the the godfather of all lathes. Quirky would actually be an overstatement as this lathe shares too many similarities as modern lathes nearly 300 years later. This lathe was meticulously hand made by Vaucanson in his later years after spending a career in the textile industry. It was designed merely to make tooling for texturing the cloth, which like most inventions, accidentally set off a chain reaction garnering popularity by others who sought after such a devise for their own needs or industry.
Throughout the years, the lathe developed to be run on line shafts for all of the 1800s and into the early 20th century. Line shaft was a remarkable form of technology designed to distribute power from a power source, usually a water mill and later coal furnace turbine, down through wooden or iron shafts all throughout a factory. These were common in the textile industry to power the cotton textile looms that often featured exposed drive belts with children operating the machines for little to no pay. The factories were run this way entirely due to the fact that although engines and electricity had been invented, such a tremendous amount of power was required to allow hundreds or thousands of machines to function. This is really where the true danger of the manufacturing industry begins. An introduction of brutal mechanical power and torque that would overpower even the strongest of men, that could wrap someone up in its grips in an instant. Specifically, exposed gears and spinning machine parts would catch workers clothing, aprons, or even long hair. This is why shop classes with power tools take these sorts of things so seriously, especially people with long hair or loose baggy clothing. Decades and decades of horrible atrocities one after another, that could have mostly been prevented with a little hindsight.
Here is an excerpt from a short story called Twisted to Death, written by The Kitchen Table historian, John Brassard Jr. This short story is based off a true account of 9 year old Frank Nead’s horrific accident in 1922.
Frank Nead smiled, his shoes slapping hard on the concrete floor of the automobile shop.
He ran with all of the boundless energy of a nine-year-old as he chased his friend, determined to catch him. Frank’s legs ached and his lungs burned, but still he ran.
The boy could see his friend, occasionally glancing back over his shoulder as he ran, determined not to be caught. They dodged around people, cars, and equipment as they went, their noses filled with the smell of oil and grease.
Without warning, Frank felt wrenched off of his feet. As he rose into the air, he began to spin at a horrifying speed. He tried to fight, but whatever had him was just too strong.
Pain wracked his body as he felt himself struck over and over again until, at last, he felt himself thrown free for an instant, and then one last white-hot pain before all faded to darkness.
When police arrived a short time later, they were greeted by a grim-faced mechanic who told them to follow him. Together they walked through the shop toward a group of machines at one side of the shop.
Looking up, the boy proceeded to tell the officers about how he and his friend, Frank, had been chasing each other through the shop. As they came over to where they now were, something had happened. The boy hadn’t seen what exactly, but he had turned around quickly when he heard his friend cry out.
He saw that Frank was spinning around the line shaft that ran the equipment in that area of the shop. The machinery ripped all of his clothing off as it twisted him mercilessly, his arms, legs, head and torso slamming hard into any outcropping of gears, pulleys, or beams that it came into contact with.
His friend had reached up to try and pull him free of the machine, but the line shaft was far too strong for the young boy, who felt himself start to be pulled into the mechanism himself. Thankfully, he was able to break free without injury.
Frank wasn’t so lucky. With one last spin, the child spun free of the shaft, coming to a sudden, brutal stop against the concrete floor.
Safety, by definition, is the condition of being protected from or unlikely to cause danger, risk or injury. By all accounts, safety is the mitigation of risk, not the elimination of it. The lathe is a particularly hazardous piece of equipment due to the nature of spinning the workpiece fixed to a drive system powered by an extremely heavy duty 3 phase electric motor. Understanding those very hazards is the key to prevent getting injured or possibly killed by any equipment with moving parts. Most modern machines, whether it be a belt sander, drill press, or nail gun will have some sort of engineering control, aka safety measures. Usually guards and/or safety switches. Even modern office supplies feature safety guards on electric pencil sharpeners or paper shredders; three hole punch. Understandably, it was difficult to make line shafts safer. Almost all guarding in the power tools world is because someone was horrifically disfigured by an exposed moving part. It’s never done preemptively. Safety wastes money, at least, that was the thinking up until about the 1990s.
The roaring 20s and the electric motor boom
While the focus of this essay is to learn more about modern lathe hazards, it should be noted that the bulk of industrial accidents happened during this time period of the first and second industrial revolutions, which is around 1780 to the 1960s. Lack of training and safety precautions for the operators as well as overworked, tired people resulted in an unprecedented and frankly widely undocumented amount of maimed bodies and limbs. Early forms of the 3 phase alternating current, or AC motor started to become commercially available by the early 1900s and were quickly strapped on and retrofitted to older existing machine tools. The idea being that you could sell a machine tool with an electric motor was a lot easier than only having customers exclusively with… line shaft factories.
This shift unlocked a whole new level of capitalism in manufacturing but also, a whole new level of danger believe it or not. Electric motors are extremely powerful, just as powerful as the line shaft but without all the exposed belts. By the 1940s, it wasn’t uncommon to see a 10 horsepower motor fitted to a Cincinnati mill or big ole LeBlond lathe. A lot of power, specifically torque was required to run this equipment efficiently. Metal cutting is a challenge because, the equipment is using metal to cut metal, in tandem with rigid machinery. Having that extra power ensured the machine could function as designed, taking up the place a line shaft would have powered previously. 10 horse power is a massive force to be reckoned with. A 10 horsepower gasoline go kart isn’t necessarily super impressive because of efficiency loss in combustion but in electric motors, that’s most likely a 12 inch diameter motor housing. A great reference to this power is a bench top grinder in a workshop or garage will usually be quarter to half horse. If the operators hand gets stuck in one of these low powered motors, the motor will most likely stall due to the obstruction. Severe injury will still be present, please do not try this at home. One horsepower bench-grinder motors are found in factories that utilize buffing wheels, to prevent motor lag. There’s a reason these high horsepower equipment is hard to find, that’s because a one horsepower motor is absolutely strong enough to kill a human being.
Understanding electric motor power and transmission
Quite simply put, the obstruction needs to over power the strength of the motor otherwise, the machine will suck the operator in and crush or bludgeon them to death. If the equipment is running in a low gear, the power is amplified drastically compared to a faster RPM, higher gear. Electric motors provide 100% torque when they are stalled, when they’re not turning, but obviously when the motor’s magnetic field is on. Now, that is just the output of the torque from the machine vis a vis electric motor. electric motors are only going to turn at one speed which is dictated by the amount of voltage coming from the power source. In other words, most electric motors only operate at one, fixed RPM. Things like a Tesla or a cordless drill will feature a variable voltage control. A device such as a variable voltage regulator can also be used on small 120v motors to adjust RPM, which is good for light duty band saws for example, or an angle grinder. This will subsequently reduce the power and torque.
Note from author: Just don’t plug your iPhone into one of these voltage converters because, it will fry it.
Now that an understanding of electric motors is established, machine tools are designed with this in mind and the motor powering the machine will be set at a fixed rpm, and the gearbox and/or pulleys will be creating the power transmission from there on out. A human being will not be able to overpower this level of power. Even if the devils advocate is looking for an argument here, there is many available sources of g*re to alleviate such urges. (show snippet of kid trying to stop lathe chuck)
(note from the author) I really enjoyed learning about torque visualized with Brick Experiment Channel where they do all sorts of insane reduction gear examples. and also, Legos are the best toy ever for young minds. If only they weren’t so expensive now a days.
The human accidents (graphic descriptions, reader discretion advised)
Starting off with briefly talking about other machine hazards, the lathe isn’t the only dangerous equipment found in most shops. It is difficult to articulate the nuances without being in the trade, but imagine a machine shop full of lathes, milling machines, surface grinders, large band saws, belt sanders, heat treat ovens, its all there. Dangers always exist in this mechanically and electrically powered world. The milling machine is a close second in terms of dangers compared to the lathe, and this is why.
Generally speaking, a persons shirt, sleeve, hair or glove is caught in the workpiece or chuck, resulting in the persons entire body to be sucked into the moving parts instantly. This can also happen when using sandpaper or emery cloth, Scotch Brite, etc. A lot of lathe operations involve the operator to use their hands on the spinning part to sand or polish the work to spec. A seasoned lathe professional will not mind this, as it is all part of the job. Seriously, there is no such thing as a perfect, squeaky clean and safety-always world in this industry. Specifications of the parts will often if not always require Scotch Brite or sand paper finishing. Deburring of threaded ends that have been freshly machined are also included, with files and abrasive stones. The operator must be extremely aware of their clothing, hair, gloves, and possibly jewelry. Once the persons clothes are caught, the rest of the body is probably going with it because clothing like cotton based garments are not so easily torn in a situation where the clothing is wrapped up layer over layer.
Note from the author: The good news is, after a couple of years as an apprentice, you will develop a sort of 6th sense, or force field bubble around your body and you will become more comfortable about knowing where your abdomen and arms are at in relation to the lathe chuck or workpiece. This is very handy specifically for when you are punching information into the DRO which is usually mounted near the chuck. I catch myself all the time going to reach for the DRO or perhaps something in the back of lathe chip pan and being like, nope, 6th sense activated. Then find a safer way by powering down the machine or walking around the entire thing if you must keep the part running. Never lean over the spinning workpiece to grab something, even if your shirt is tucked in, unless you want to be turned into a raspberry slushie.
As recently stated, the machine does not care. It will not stop wrapping a human body around until an unfortunate coworker has to come and turn the machine off. This is almost always the case in lathe fatalities. The machine will keep turning without a care in the world. This is especially dangerous with smaller diameter work, say 2″ to 12″ or 50mm to 300mm. These diameters are most dangerous because really small diameters are less likely to wrap up clothing and larger diameters simply become too large to really cause sleeve wrap ups or sand paper catches etc. However any diameter can cause fatalities. Bear in mind, large diameter work causes a new level of dangers with crushing hazards and possibly turning too high of RPM rated for the machine, or straight up getting crushed.
Unfortunately, there is a certain imminent danger always present when operating lathes, or any machine tool. The issue with the lathe is the operators body, torso specifically are within very close proximity to the lathe chuck or work piece when cranking the handles or making adjustments to the tools, or DRO. A lot of machine shop accidents in modern times happen more frequently in places such as china, Russia, or South America, not necessarily tied to lack of expertise by any means but by the staggering difference in industrial workforce compared to Europe or North America. In the United States, the Bureau of Labor Statistics did a nation wide study of fatalities from workers being caught in machinery in 1997. Reportedly half of the workers were performing service related tasks which could include moving machinery, or rigging, also maintenance, unjamming, cleaning, etc. These all qualify as “machinery fatalities” because easily half of machine shop work is setting up and being in close proximity to the moving parts or dangers, not necessarily pertaining to ‘manufacturing a specific item.’ The total number of fatalities being manufacturing related was 78 workers, making up 48 percent of the total from this year in the united states. Also according to the BLS, in one of the most recent studies in 2021 reports 115 workers were killed in the manufacturing industry alone, in incidents specifically relating to the contact of objects or machinery. Unfortunately they do not specify lathe injuries or fatalities, one can only speculate.
In countries that primarily profit from manufacturing, there will be a staggering amount of accidents compared to countries without this density of manufacturing workforce. It is not in anyone’s best interest except possibly the victims family to report on such events. The BLS does not specify any companies names in their statistics which, rightfully so, would be an irreprehensible stain on that company’s name. So globally, this research will have to just adhere to sticking with nationwide findings.
In a case issued by Kentucky State Fatality Assessment and Control Evaluation Program from 2021, reports on an incident with a very well seasoned machinist with certainly a lot of experience considering his age.
“A 52-year-old machinist at a manufacturing company was preparing to spot drill the center of a 103-inch [long] piece of round steel in a manual lathe. [likely 2 to 4 inches in diameter based on throat size of most CNC lathes] Because of the length of the steel, 24 inches of the material was protruding out of the back of the unguarded lathe, held in place with an aftermarket clamping device that rotates as the lathe rotates. Security footage showed that while the lathe was in operation and the steel rod was spinning, the machinist attempted to grab a glove from the top of the lathe. The sleeve of his shirt became entangled on the clamping device, pulling him into the lathe between the motor and rotating piece of steel. As the lathe continued to turn, the machinist’s body rotated around the piece of steel and struck the motor about 12 times. An employee in the changing room heard the event, ran out to investigate, shut down the machine and called emergency medical services. First responders transported the partially conscious machinist to a hospital, where he was pronounced dead on arrival. Cause of death was listed as traumatic blunt force injuries.”
It sounds like the employee that stopped the machine was in close proximity and could hear the victim most likely screaming for help. This situation likely happened so randomly, unexpectedly. Albeit most of the time people who speculate often pander towards it being strictly the employees fault, a good point was brought up by commenters on this report.
Brian Hill says,
Any one of many basic a safety procedures would have protected this guy. So sad this looks ever so much like complacency from this very limited view we get from this article. Prayers to the co workers and family.
While another commenter reconciles with:
I totally agree with Mr. Brian Hill. Complacency appears to creep on everyone at some point. Be focused all the time is a necessity and at times that is hard to stress to the employees, with scheduling jobs on a timeline. But Safety has to be the main focal point at all times.
Complacency is so, sooo common in this industry. Especially in the world of programming and automation. He was just doing normal work, setting up a pretty long piece of steel. What caught his clothing was the four screw clamp on the back side of the throat of the lathe, which was used to support the rear end of the protruding shaft. The image included in the report shows a very common type of device also known as a spider chuck, which presumably the very long extended set-screws sticking out of the OD were acting as a 4 screw saw blade that sucked the operators clothes in. Most of these commenters agree, this is really not the operators fault. A device like this should have some sort of removable guard or engineering controls that allows access to but also prevents dangers to the operator.
Authors note: And I agree, I have worked on two large lathes with this spider feature and i found it pretty sketchy and I never really appreciated the danger of it until reading this article. Exposed screws and bolts on a already dangerous spinning diameter is really a huge hazard and I hope that people who use spiders on their lathes take this precaution seriously.
The more you research this topic, the more graphic it gets. Russian lathe accident seems to be the provider of most of the modern internet era lathe gore micro-doses. What is left of the human body after such an entanglement is the shiny metal workpiece, wrapped in a humans clothes, with the humans guts and blood strewn about radially in the pattern that would be similar if you’ve ever put cutting oil on a lathe piece while it was turning at 1000 RPM. The ceiling is not exempt from the blast radius. This has nothing to do with the ongoing war between Ukraine and Russia, all this stuff happened way before 2022, and possibly before 2014.
Warning, extremely graphic narration. No images. Click of the video now if you do not wish to here a real life g*re video explained.
Authors note: My classmates and I used to research this stuff when we were in high school machine shop class. I think it helped us fully understand the sheer power of this equipment and what it can do to a human body.
There are many situations lathe workers have found themselves dead in. This one example was not a video but a series of digital camera photographs of a worker wrapped up in a lathe on a 3 inch diameter shaft or so, with just his legs with blue pants remaining attached to the tangled clothing articles and the lower half of his torso still pretty intact. But from the torso up, there isn’t much left but a pile of remains in the bottom of the chip pan. Based on the photos being 4×3, it is likely in the early 2000s. These photos can be found on a forum posted in 2007. The photos were obviously sourced the photos from a g*re website based on the huge watermark. The victim is of Caucasian skin complexion but it is difficult to find any more information on the guy and where this took place. Some of the forum users pointed out an eyeball in the pile of remains. It honestly could very well be from anywhere in the world. The poster of this we’ll call RD made a great comment later on that reads as follows:
You know… In all the years I’ve been machining at various shops, mold shops, prototype shops etc.. “They” have taught me a lot of things, about math, tooling balls, even something simple like how to square a block.. But I don’t remember “they” really ever teaching me anything about “safety.” Common sense rules apply in a machine shop from my experience. When you watch a lathe rip off 1/8th inch passes of steel and it doesn’t even put any strain on the motor, you can only imagine what it can do to something made up of 96% water.
Another commenter writes:
Man that was brutal! I work in aerospace and we have all kinds of nasty lathes mills etc.. One thing that we stress is don’t get complacent around any kind of machinery.
In this final instance, a security camera video of a worker from around 2021 supposedly in Russia Is seen working on a manual old school lathe, most likely machining journals to the ends based on the high RPM. The man is wearing a long sleeve winter puffer jacket which is extremely dangerous, and frankly stupid. It is presumably very cold in this factory though, it is unlikely he is wearing this for fashion. He is working on steel shafts probably 6 feet in length and 3 inches in diameter, or around 1800mm by 75mm. probably 200 lbs. each. He is seen reaching over the workpiece with his right hand, basically with his belly folded over the 75mm diameter piece reaching down into the chip pan. The machine is off while he does this maneuver. It looks like he accidentally starts the machine with his left hand where the machine then jams with his body in an awkward position now. He is holding the entire torque of the machine with his left leg, probably very aware of the situation for exactly 5 seconds until his strength fades away and the machine over takes him. With his one arm most likely broken and wrapped around once, jamming into his body, the machine from a muffled stalled electric sound whirs up at this sudden weakness in the obstruction and sucks the man in, most likely killing him not instantly, but after a couple of rotations. He is whipped around at what looks like at first 200 RPM as the lathe gains speed, and in a rapid crescendo climaxing at 500-600 RPM with the remainder of his internals and work boots dispersed in a 20 foot radius around his work area. After 30 revolutions or so, or exactly 12 seconds, an innocent older coworker runs through the bloody mist and around back to the rear of the machine where the power switch is. Stunned in disbelief, he can’t believe what’s just happened as his coworker is carried around a few more times as the lathe powers down. To make matters worse, this video is also accompanied by a few close up shots of the aftermath. It is much worse than the previous instance. There is absolutely nothing left except tangled wet clothes and blood.
And as they say, that’s enough internet for the day. May he rest in peace.
The good news
Fortunately, there are many things a lathesman can do to avoid these if not all injuries or hazards.
Rule #1 never wear loose fitting clothing or long sleeves
This mostly pertains to long sleeve shirts or jackets that could be caught up in machinery resulting in horrific injuries or death. It is recommended to wear a short sleeve T shirt, or at the very least, roll up the sleeves to be above the elbows if working in winter conditions. Wear long pants and closed toe shoes. Long sleeves is what killed our friend blue pants.
Rule #2 never wear gloves while running machine tools
Gloves can get caught in moving parts and take the entire hand, arm and body with it. Do not wear fabric based gloves when using machinery with moving parts. Latex gloves are OK sometimes because the latex film will break when caught in machinery. Latex gloves are for loading in parts to the chuck or vise while the machine is stopped. Do not wear latex gloves or any gloves when sanding or filing lathe parts. Cotton, leather, Nomex, Kevlar will not break and will pull your entire body into the machine if caught. Even if it is freezing cold, it is much safer to have an electric space heater near the workstation than to have any excuse to wear fabric gloves.
Rule #3 never use a cloth rag to wipe down rotating shafts on lathes
This ties in with rule 1 but worth mentioning. This could have also been the cause of lathe accidents as wiping down a shaft with a rag is a pretty intuitive thing to do especially when using oils and tapping fluids. Always stop the machine. At the very least, use something like paper towels. Cloth rags, like clothing, will not rip off like you think. It will coil up anything in its path including arms and possibly legs.
Rule #4 be careful when using abrasives or files
Sandpaper can also get caught in moving parts of any machine, with lathes this is very specific to sanding the OD or ID of the part. Do not pinch the sandpaper with one hand, always use two hands and hold the strip of sandpaper gingerly with both hands between thumb and pointer finger, and always be pulling back away from the work. This way if something gets jammed the sandpaper will get pulled from the hands and since the operator is leaning back, they will fall away from the work rather than into it. Be sure to hold files correctly as well. Hold files in the same fashion with thumbs and pointer fingers, do not grip the tang of a file in the palm. In fact, It is not recommended to use a file without a proper file handle to protect the hand from tang injuries.
Rule #5 stand to the right side of the chuck when turning on the lathe, and when machining.
Do not ever stand directly in front of a work piece while it is being machined, it is recommended to stand just to the right of the work and chuck. This is to avoid injury from part ejection, while also still allowing the operator to observe the work practically.
Rule #6 wear safety glasses and other PPE while machining
Safety glasses while using manual machine tools of any sort is a no brainer these days. They cost all of about two bucks, maybe 50 dollars for prescription. It is not worth losing an eye, safety glasses do a good job to de-murphy the workplace. Respirators are also a good idea when using abrasives or other processes that cause airborne particle separation, such as sanding aluminum and cast iron.
The lathe is, unfortunately yet axiomatically the most dangerous machine shop tool out there. Between many cuts and scrapes from milling machines, or certain death on the lathe, the lathe is the tool of choice for the grim reaper. It is simply a mechanical tool to process machined objects via turning, into usually high tolerance parts for other machines. The risk and nature of it is, frankly quite profound across the board compared to other machine tools. It was not in its intentions to be so dangerous and foreboding, but it quickly became a necessary evil and a lot of people refuse to even work on lathes. It takes a special mindset to always keep the body away from any moving parts. In a strange turn of events, the lathe started off pretty harmless, then went through several evolutions that made the line shafts infamously dangerous. Now, modern lathes are juggernauts with incredible torque and power that should never be underestimated by anyone. Complacency is the enemy.
Note from the author: Please be careful with sandpaper and files, always stand to the right side of the chuck so nothing can hit you in the face. And never wear gloves. Thank you.
