Please Don’t Do This

Yesterday I took a 2×4 and my angle grinder with the diamond cutoff wheel, and snapped a couple of “here’s why not” pictures.

It was so depressing I decided not to post them. Also, they didn’t look like much – a bunch of shredded wood with some deep cuts in it. It would have been more illustrative if I’d gone and ruined some steak but that would be an uncool waste. So I’m just going to preach at you without supporting illustration.

This is a screen shot from a video by one of my favorite youtubers, a Ukranian metal artist who goes by “shurap” (Yevgeny Shevchenko, I think it is) [yt] I know he knows what he’s doing and the fact that he was able to post a video at all tells me that he completed the exercise safely. But it made my flesh crawl to watch it.

First off, cable is nasty stuff to cut with a grinder, in the best of circumstances. Secondly, the fact that he needs to support the cable with his hand means it’s likely to droop and the cutoff wheel might bind. If that were to happen, where does the grinder and the cutoff wheel go? Yep, right into the plumbing on the inside of his wrist.

Now, he’s strong as hell (look at those hands!) and he’s got a good choked-up grip on the grinder and is working close to the vise, etc, but given all of that he could have just as easily positioned the work-piece vertically in the vise and had no problem at all. There’s a really simple rule for angle grinders: if you always hold them horizontally, they can never kick vertically – which means that they can only hit the person standing next to you. So, never have anyone else in the room and always hold it horizontally (use the support handgrip, too) and you cannot have it kick in a direction that includes you.

Back when I did internet security for a living, and before when I wrote code, I discovered that I’m unusually good at seeing how things are likely to go wrong. I guess it’s just how I learned to think, probably a result of too much strategy gaming and playing too much chess. It was probably the chess: my chess-playing is an exercise in “all the things you can do wrong” and you’ve got the entire end-game in which to perform your damage assessment. I always seemed to be able to walk into a situation and tell my client the top 5-10 things that were most likely to bite them, and how to avoid them. Then, years later, I’d return to manage the incident response and it was always, “now that you have done that thing I told you not to do, and it bit you, let’s see what we can do to undo events.” If my life-experience were to hold true that means Shurap had better “waste” a few seconds managing his work-piece a bit better, or we’ll see his youtube channel go dark and silent for a few months while he heals. I’m trying to be a bit “light” about this, but I’m deadly serious.

Here’s another one, from another hero of mine, Walter Sorrells. He is demonstrating putting a grabby new 38-grit abrasive belt on a grinder, and then reaches across the belt to turn it on:

That’s a 2 horsepower motor with a capacitator start: they turn on and they’re going and, if his sleeve caught on that belt, he’d be lucky if his shirt disintegrated before his arm did.

When you’re working with any tool, it’s a good idea to leave everything turned off and take a look around, then mime your normal operation with the tool and see if there’s anything you haven’t noticed. For example, I have a heavy rubber mat on the floor in front of my Bridgeport milling machine – because I don’t want there to be any reason I’d suddenly lean forward to catch something before it falls on the floor; now I can just let it hit and it won’t break. Extra plus: if something rockets off the mill and toward the floor at high speed, it’ll dampen the bounce. I’m not worried about that because milling machines operate horizontally, which means I am mentally prepared to get below the plane of the mill at any moment. For $45, you can bet there’ll be a big rubber mat in front of my metal lathe, for the same reason – lathes operate vertically, which means you’re a target. And that photo of Walter is a case study in how to self-inflict death by lathe.

I’m not saying this to criticize these people, who I hold dear. This is more to serve as a reminder to myself that you can never be casual with machine tools. Or, machines in general. As I’m setting up my new shop, one of the things I have been doing is running over and over through my head, to visualize my work-flow and make sure that there are no things I can trip on, that can grab me, or set me on fire. Back in 1981, when I got my first motorcycle, Fred M, who taught me how to operate the thing, told me “always ride as if the cars around you are going to suddenly try to kill you.” Fred’s advice saved me a great deal of pain. I think I’ve internalized it to the point where a part of me acts as though the Bridgeport might suddenly turn itself on while I’m changing mills. Who knows, when the machines rebel, it might.

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I use a diamond cutoff to chop chunks of my 1 1/2″ high carbon wire rope. That makes a tremendous mess and it’s hard to arrange things so I can come at it horizontally, but – I do. Even if it means shifting the entire 750-lb spool. I like my fingers that much! Also, when cutting wire rope, have a small roll of cheap utility wire and some pliers; take a turn around the wire rope and twist it tight, so the wires won’t try to untwist. It takes a few seconds and you waste 8″ of wire. Once you’ve got it cut it won’t untwist when you put it in a vise and tack the top and bottom together with your MIG welder.



  1. says

    Oh gods, that’s why I cannot work with my FiL. The guy thinks that safety is for pussies (I told him that’s no problem, I got one, it’s wonderful but no place for an angle grinder) and I don’t want to be there when he finally kills himself.
    As for motorbikes, sadly most bikers seem to have had an instructor who told them “act as if you’ve got Star Trek shields” around you.

  2. Dunc says

    Why do that sort of work with an angle grinder at all? Just buy a frickin’ cut-off machine and bolt it to a bench – then it’s definitely not going anywhere.

  3. says

    Agreed – that’s what a chop saw is for. I have one of those, but it’s easier to bring an angle grinder to the 700lb reel of wire rope than it is to bring the wire rope down the hall to the chop saw.

    I’m actually kind of worried about the chop saw because those big grit wheels look awfully nasty, and I like the non-breakable steel diamond wheels more. They’re decidedly nasty too, of course. Anything that cuts through steel like that is nasty. You’ll notice I do not use the oxyacetylene torch, even though it’s faster and easier – because it’s nastier still.

  4. Jazzlet says

    I have a friend who made the mistake of cutting a piece of wood with a table saw at the end of the day when she was tired, she hit a knot. She has one and a third fewer fingers than normal, and real problems using a hand saw as she no longer has a pointing finger. So yes think your work through, imagine the worst that coud possibly happen, and take action to minimise all of the risks you can.

  5. Some Old Programmer says

    The motorcycle maxim I learned was, assume 90% of all drivers don’t see you, and the other 10% are trying to kill you.

  6. Some Old Programmer says

    I recently acquired a table saw, as I have several rooms to trim out in baseboard and molding. Being the nerd that I am (and inexperienced) I thoroughly read the instruction manual; I’m very glad that I did. Just recently I had the push stick slip a bit, and seemingly instantaneously the tip of the stick got sheared off and rocketed across the room. I’d much rather garner a healthy respect for a tool earlier rather than later.

  7. says

    @Dunc, I have to cut steel with a hand-held angle grinder in a vise, because I do not have a place for a huge cut-off machine. It simply won’t fit into my workshop. Plus such machines cost money and not everybody has enough money to just buy all the special tools for all the special tasks.

    For the sake of safety, I do intend to build or buy a small stand for the angle grinder. Until then, vise and angle grinder it is, no matter how much I do not like doing it.

    That being said, when cutting with an angle grinder in a vise I always take care of a few things:
    1) I take care the cable is out of the way, i.e. behind me.
    2) I take care to cut in such a way that the drooping piece of steel cannot pinch the wheel
    3) I hold the angle grinder in both hands
    4) I watch where the sparks fly
    5) I never work without the safety cover for the wheel

    I had a shirt being caught in a small handheld belt sander. It was not a pleasant experience, and luckily only the belt sander got damaged and not me. Since then I am a lot more careful with clothes around spinning machinery.

  8. says

    Plus such machines cost money and not everybody has enough money to just buy all the special tools for all the special tasks.

    And the more saws you have, the more saws you need.
    I have a small (for resin) table saw, a chop saw (actually said FiL’s), a handheld rotation saw, a bad jigsaw, a good jigsaw and an array of handsaws. And the angle grinder. You always seem to have a saw that does the job but is not the optimal solution.

  9. Dunc says

    Marcus: given the amount of money you’ve spent on your setup so far, you could buy another cut-off machine just for the wire rope and place it wherever works best for you.

    Charly: there are plenty of small reasonably-priced saws out there. I’ve noticed myself doing this sort of thing – I’ll baulk at paying a few tens of pounds for sewing machine attachment, when I’ve spent hundreds of pounds on fabric without blinking. It’s almost always worth buying the right tools for the job. Sure, you can get by without them, but even if you’re not risking major injury, you’ll usually save enough time that they pay for themselves.

    My old man wasted years of his life bodging around with sub-standard or inappropriate tools… If there’s one thing I’ve learned from him, it’s that you should spend more money on tools. Find the best tools you think you can afford, and then buy better ones. You won’t regret it.

  10. cafebabe says

    Chopping up bits of metal is always a bit of a compromise. My metal bandsaw is low risk, but doesn’t work for everything. Angle grinders are the spawn of satan, but very convenient. I used to find a fierce joy in wielding an oxy-acetylene cutting torch, but I don’t want to be in the same building as one any more now. Like you say, you must think about what might go wrong and avoid all such. Even so, there are some machines I will only use when someone else is home … just in case!

  11. says

    Dunc, that’s pretty arrogant. Really, not everyone has the money and the space for that.
    I’d be hard pressed to justify a 500 bucks table saw I’ll use twice a year to my family…

  12. Dunc says

    Obviously you have to strike a compromise, but for key tasks in a hobby you’re spending a lot of time and money on, not buying the right tools is a false economy.

    I’m not exactly rich, and I’m very tight on space. I’ve had to give up hobbies entirely because I didn’t have the space to set up safely for what I wanted to do, or because I needed space for something else. I’ve completely re-organised my living space to fit stuff in, and I’ve had to get very inventive to do it. Believe me, I understand space limitations.

  13. voyager says

    Safety cannot be undervalued. The Mr. V. lost 2 fingers to a press machine (his fault) and the vision in one eye from a flying piece of metal (not his fault- wrong place, wrong time) and let’s not talk about the motorcycle accident 30 years ago that wasn’t his fault, but ruined his leg anyway. Making it to 65 has been a bit daunting for him.
    My dad always told me to buy quality tools and good safety gear. Also, to always read the instruction manual.

  14. says

    My old man wasted years of his life bodging around with sub-standard or inappropriate tools… If there’s one thing I’ve learned from him, it’s that you should spend more money on tools.

    One of the few times I saw my father really angry was when a neighbor gave their kid some “kids tools” – useless crap that was too small/too dull/too flimsy and my dad explained that the parent was not protecting their kid, they were increasing their chance of injury. When I started using knives more, I realized that dull knives are much worse than sharp ones – you’re more likely to use too much strength and have something slip (I know you already know that!) So, much later when I gave someone’s kid one of my older DeWalt reciprocating saws for a craft project, they freaked out at me and I had to deal with all that. That was how I learned not to (generally) give people tools, unless I am sure they have a clue.

  15. says

    I have a shiny straight line up the back of my right index finger from where the safety guard of my angle grinder shifted and I just slightly brushed the back of the finger on a diamond wheel. Just to make the experience more memorable, the wheel was probably about 1000F at the time, just below red hot. So it cauterized some of it and shredded the rest. I won’t post pictures because of that whole vasovageal response thing.

    As Aleister Crowley ought to have said, “DO AS I SAY, NOT AS I DO, SHALL BE THE WHOLE OF THE LAW.”

  16. dangerousbeans says

    I think I remember seeing a portable hydraulic cable cutter on mythbusters, maybe you could get one of those?
    The angle grinder is one of the scariest tools in my shop. I’m glad I bought a big one: I can’t hold it one handed, and even with two hands i feel the torque when I turn it on.
    I’m going to have to think how I turn on my grinder now

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