Zipppp – PING!

This scared the shit out of me. And, worse, I subsequently figured out a better way to do what I was trying to do, anyway.

The details of what happened are not 100% certain, unfortunately. The short form is, I fired up the table saw and when the blade got up to speed suddenly there was a snap and something hit my glasses right over the front of my left eye.

Whatever it was, it hit so hard it knocked my glasses off my face. There’s now a largeish chip exactly where my left eye would be if it had been exposed. And suddenly, I felt like all the money I spent on impact-resistant lenses was a good idea. Naturally, I have shop glasses, too, but I was wearing my “daily drivers” which were still good enough to take a bullet for me.

I am pretty sure if it had hit my face, it would have embedded itself – those poly/acrylic lenses (basically, Lexan) are tough and it really took a whack. If it had hit my eye, it would have gone right through the iris and it bears no further thought.

What happened? One possibility is “foreign object damage” – perhaps I left a screw on the table and it somehow came into contact with the blade. The trajectory was interesting – I am pretty much always off the axis of my table-saw or lathe – and whatever it was came flying at about a 20 degree angle. Another possibility is that a tooth chipped off the blade and decided to fly toward me. I had just changed the blade in the saw and it’s possible that the blade wasn’t fully tightened, though I checked that afterward and it seemed OK. [The theory there is that the blade wobbled on the arbor and hit something and knocked a chip of carbide off]

Always wear your safety gear!

Yes, if I had been wearing my face shield (I usually wear a face shield with earmuffs while using the lathe) it would have absorbed the impact nicely. But, I wasn’t.

If I were a Texas republican, I’d make some comment about how it’s creeping nazism to require people to wear their face shields or safety glasses when using a table-saw! Bring back lawn darts and riding motorcycles without helmets. [I live in Pennsylvania, which has a huge population of deer, and it’s distressing to see motorcyclists noodling around with their remaining hair in the wind, no helmet, no goggles, etc.]

So, what was I doing? I was trying to make a finger-board for a box joining jig I’ve been making. It turns out that making a finger-board is not super easy (you can buy them for $25 but I was being stubborn) – I had been doing a lot of moving and clamping a piece of ABS plastic to a mitre, and measuring with a micrometer. That’s for the birds! Meanwhile, I stumbled across a completely different solution which is embarrassingly simple: suppose you want a 1/2″ fingerboard. Well, you carefully set the rip fence and cut a few strips of oak that you can mic to exactly 1/2″. Then, you cut a few lengths of that, cut them into 5″ chunks, glue and stack the chunks side by side, clamp them well and – boom! Fingerboard! It’s so easy I really feel like I ought to kick myself. Here, I had been thinking of doing something in aluminum using the milling machine and a 1/2″ end mill, but it doesn’t have a DRO and I’d be right back to cutting and mic’ing until my brain bled.


  1. billseymour says

    If I were a Texas republican, I’d make some comment about how it’s creeping nazism to require people to wear their face shields or safety glasses when using a table-saw!

    LOL!  Made my day.

  2. outis says

    Craaaaaap, thanks for this terrifying reminder.
    I also stay out of axis with my (not at all large) table saws, but stuff flying out at an angle? Never considered it, I must confess. Time for new and thicker safety goggles, right bloody now.

  3. Jazzlet says

    Yikes! But yay for impact resistant lenses! Glad it (whatever “it” was) didn’t hit anything more delicate, doesn’t bear thinkig about as you say.

  4. lochaber says

    10-15 years or so back, my eye started bothering me. Mostly when I went outside into the light. eventually spent some time up close with a mirror, and could see a little ring around a tiny speck in my eye. tried splashing a bunch of water and dunking my head, then tried to prod it with a moistened qtip.

    not sure what else to do, I went in to the student clinic (had mediocre health plan through the school), waited for an hour or so, and was told to leave and go to the urgent care clinic. :/

    Eventually got to see some student doc, they looked at my eye, told me I had a tiny little splinter of metal in the cornea. irrigated it with saline, then tried using a moistend qtip (validation! I did the right things!), and eventually had to poke it out with a tiny gauge needle. They did say it would have eventually been pushed/grown out even if untreated. Not too bad for ~40 (maybe less so considering the semester fees for the plan…)

    Best I can figure, was a couple days before it was bothering me, I was using a dremel to cut/grind a bit of angle iron, and of course I wasn’t wearing safety glasses. That was a pretty cheap and relatively benign lesson, so I wear safety glasses now. my blink reflex is only effective on particles big enough and slow moving enough that I can actually see them, and there are a lot of things too small and/or too fast for my vision to detect that can potentially compromise my sight…

  5. says

    On the one hand, terrifying.
    On the other, it managed to aim squarely for the most armoured part of you.
    Imagine all the other fleshy bits it could have seared clean through on its journey.

    Many years ago I had reason to replace my sister’s oven after it had made a loud bang and stopped working.
    Simple enough job, even after I discovered that whoever wired it in had swapped the wires, and the socket was live.
    It wasn’t until we had it disconnected and moved it away from the wall that we found one of the screws from the socket WELDED to the back of the oven…
    Apparently that was the bang. Sometimes you have to thank providence for the near misses.

  6. says

    Ian King@#6:
    Sometimes you have to thank providence for the near misses.

    Per the implication of chigau’s comment at #1, another possibility is that god was trying to kill me and has bad aim. If the person standing next to me had burst into flame, or an airplane had crashed into a city nearby, I’d believe that. Remember the way he smote New Orleans when he was aiming at Mississippi? Yeah, his sights are off.

  7. says

    they looked at my eye, told me I had a tiny little splinter of metal in the cornea

    Rare earth’s magnet, placed in a condom, then put against the surface of the eye has a good chance to removing those splinters.

    I first started grinding knives in high school (basic “prison shiv” stuff) and one of my early experiences involved a chip of carbide that bounced off my cheek and angled up under my glasses, penetrating the surface of the eye. It took a day to get medical attention to have it removed (late 1970s) and it left a permanent bump on the surface of my right eye, which prevents me from being comfortable with contact lenses.

    I’m glad you came out of it OK. My eye doc, at the time, said something about iron chips encouraging bacterial growth and infections and that I could easily have lost the eye.

  8. dangerousbeans says

    yikes, scary. if it’s a carbide chip i would be worried about the rest of the tooth failing.
    have you seen the slow motion videos of saw stop systems stopping carbide tipped dado stacks and the carbide failing? those are impressive

  9. lochaber says

    Marcus Ranum@8:

    thanks, but, yeah, all considered it could have been much worse, and I’m much better about eye protection now.

    There’s an image floating around the web that I need to find and post at work (some people are a little too lax about PPE…), where someone had an angle grinder disc break, and a good chunk of it is embedded in their safety glasses. it’s a pretty scary pic, I imagine you’ve seen similar…

  10. lochaber says

    forgot to mention, that’s a pretty clever bit with the magnet and condom, hopefully it’s not one I ever have to personally use or even recommend to someone else, but thanks for mentioning it.

  11. lorn says

    Back in the 80s I worked as an electrician on a SPY-9 FAA site in the middle of winter in Florida. Those sites have a huge amount of grounding involved. Essentially the entire site is covered with a grid of heavy copper cables. These are buried in about 18″ deep and every place one cable crosses another we would use a graphite mold and glorified thermite fortified with powdered copper (Cadweld) to weld the cables together. We would also Cadweld the cable to fence and gate posts, and pretty much everything metallic on the site. We joked that you didn’t want to park too close because the crew was “Cad-happy” and likely to weld your vehicle into the grid.

    Cadwelds, done right, are amazing. Essentially you are pouring molten copper around a connection. If everything works you have the cables melted and fused into a solid monolithic mass.

    Unfortunately this was the middle of Florida in winter. Not much below freezing but cold and wet. Every front would bring rain. When it was cold the ground would freeze and dry but be rock-hard. Then the rains and it gets warm, and the clay turns to muck deep and sticky enough to pull your boots off. This cycles repeats every three days or so.

    The problem is that molten copper doesn’t get along well with water. Water turns to steam and in the confined space of the mold it tends to go off like a bomb and splatter molten copper everywhere. Keeping the cables and molds dry was a Sisyphean struggle given the frequency of the rain. One day we made a weld where we were pretty sire everything was dry and it still blew up.

    Despite hardhats, safety glasses, gloves and some significant distance the senior guy got a small burn on his cheek. No big deal until we looked closely at the safety glasses. The lens had a hole in the middle and a track where a single drop of molten copper had run down the inside of the lens and touched his cheek.

    He had to sit down for a bit. He keeps those glasses in his tool box to remind him, and anyone else who will listen, that construction work is hazardous and safety glasses are vital.

    It takes just a fraction of a second to lose an eye. Yes, safety glasses are a pain. But far less painful than losing an eye.

    I’ve found that the higher priced safety glasses are much more comfortable. I prefer the type that folds flat with side guards instead of the nearly ubiquitous wrap-around type.

  12. says

    One day at my previous job the janitor lady came when I was still working and we chatted a bit. I was wearing my protective glasses for a relatively innocuous work and she commented that her former boyfriend did not wear them while drilling aluminum and a splinter got to his eye. He refused to go to a doctor to have it removed, saying that it will be pushed out on its own. It did not. It got infected and he lost the whole eye.

    I am glad that nothing happened to you. I am permanently horrified about eye injuries. I got my cornea scratched by a willow branch a few years ago and ever since then I wear eye protection even for pruning.

Leave a Reply