Why such a difference in price? Bionic face shield.

Discussion in 'Woodturning Health & Safety' started by odie, Sep 9, 2014.

  1. Steve Worcester

    Steve Worcester Admin Emeritus

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    it depends on where it would hit. The impact would likely move the entire shield. If it hit lower, as with any face shield, move the headband and allow the chin protection to contact the breast plate below the larynx area and into upper sternum. Which in my non medical opinion is a bit more impact resistant than the jaw
     
    Last edited: Sep 12, 2014
  2. Mark Mandell

    Mark Mandell

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    Riot Gear

    Not to discourage Odie in his experimentation, but I have some serious qualms about using an adapted riot face shield in this application. Here's why

    1. Riot gear is designed to help protect "cops" (regardless of which uniform is worn) from objects thrown at them. A heavier, more rigid plastic may work reasonably well in the application, especially when the officer can anticipate and actually see what's "incoming". When chunks of wood get rocketed into our face from 2' away, we'll be lucky to find out later what hit us. In our situation, a more rigid shield may work against us when, instead of flexing to spread the impact over a wider area around the impact point, the entire shield gets slammed into our face and head. In that situation the shield could wind up doing as much damage as the wood. Adrien Coblentz here in New Jersey was wearing a face shield. The surgeons removed parts of it from his brain.

    2. The use of the metal clips is of particular concern for me because, like my comment about having a mouthful of "Resp-O-Rator", I'd not want metal edges flying around like razor blades inside that shield in an impact situation, and I have no doubt the clips will come loose when the thinner headband deforms or breaks on impact.

    Let's remember the physiology of our getting hit with a heavy/forceful object. The strike actually involves three impacts. First, the object hits the shield. Second, the shield hits us. Third, our internal organs impact our inside body "wall" (abdomen or skull). An effective shield must absorb and dissipate the first impact to prevent the 2nd and 3rd. The riot shield may be very resistant to point penetration, but to truly protect us, the support structure (headband, mounting elements) have to work just as well. In a serious impact, flimsy head straps and such will not be able to handle the energy and will either fail completely or will transmit a great deal of impact energy into our brains and spinal column. Energy absorption is the concept behind the airbags in our cars. They can't protect us from the other car. Instead, the bags inflate, pull the speed-impact energy from our suddenly-moving body hitting them, and then dissipate it by deflating more slowly to reduce or eliminate the force with which, without them, our bodies would hit the rigid parts of our own vehicle.

    I still remember my high school physics teacher's comment that "The laws of inertia are a BIT**. Just ask anyone who's been in a car accident." The ongoing controversy over football and hockey players' concussions, notwithstanding serious helmets, shoulder pads, neck braces, and such, is another prime example.

    A truly effective impact shield for turners needs to be able make use of our entire body's 150 to ??? pounds of inertia to counter the kinetic force of that bullet chunk of wood. I seriously doubt that any kind of head gear is going to be able to do that.
     
    Last edited: Sep 13, 2014
  3. john lucas

    john lucas

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    Wood turning is dangerous. Hmmm
    M depends on what you turn. Bowls platters hollow formsi and crappy wood maybe. I've turned hundreds and hundreds of wine stoppers boxes Christmas ornaments hand mirrors earrings pendants etc. there's no danger there. I'm not saying you don't need a face shield I'm just not comfortable calling our hobby dangerous. We should respect the potential hazards of course
     
  4. hockenbery

    hockenbery AAW Advisor Staff Member

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    Statistically, you are unlikely to get hurt turning wood. Probably much less likely to get hurt woodturning than riding a bicycle or crossing a busy street on foot.
    But small pieces of wood can cause serious injury. The potential for injury from a splinter to lethal accidents is there and needs to be considered.

    I used to think small pieces would not hurt us. Then I saw an accident where a 3x3x4 piece came off a mini lathe! hit the tool rest and then the mouth of a person wearing safety goggles. The result was an emergency room visit, 12 stitches, and a week wait to see of the front teeth to re-root. The guy is a really good turner who lost focus for 10 seconds in a room full of people.

    This was a box or ornament size piece. I have turned hundreds maybe thousands and never had one come off the lathe.
    That history of success doesn't mean the next one won't come off. I like my odds but!
    The accident happened because of too high a speed ( wrong belt on a mini lathe) and a tailstock not locked in place.

    Had the individual been wearing a bionic face shield or better there would have been nothing worse than embarrassment. Embarrassment is easier to get over than stitches and emergency room bills.

    Most of our protective gear won't protect us from everything. But even small blocks can lead to emergency room injuries or worse.

    John, you probably would never start a lathe without checking the belt position.
    You would probably never start a lathe without checking the lock on the tailstock
    Never start a sliding headstock machine without checking the lock on the head stock.
    You would never pull a box out of a chuck.
    I like your odds too!

    I saw a world renown turner launch a box off the knee cap of a front row symposium attendee twice in 3 minutes.
    A different trajectory may have caused it to hit the tool rest and then the turner.

    Woodturning has risks no matter how small the work.
    To put it in context, I feel a lot safer turning than walking on the street.

    Al
     
    Last edited: Sep 13, 2014
  5. Mark Mandell

    Mark Mandell

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    "Never say 'never'" As soon as you do, it will. We can all hope for the best, but we must plan for the worst to have a real shot at our dreams. What's the stock broker's favorite line(?) . . "Past performance is no guarantee of future results."

    nq060413.gif

    Again, let us keep this subject in perspective. A $10 flip-up plastic visor, especially with added safety glasses, will do a fine job of keeping shavings and chips out of our eyes. It'll do an OK job of preventing us getting splattered with some liquid that's been applied to something spinning on the lathe. We don't need $60 or $800 rigs for that. It's the catastrophic failure of a spinning piece of wood, likely due to an internal defect that we either missed or forgot to look for, that's going to be the one in a hundred or a thousand or ten thousand that gets us, and there is nothing to prevent that from happening the very next time we turn on the lathe. If we play the percentages and statistics game, we're asking to become one.

    "Hey, Bubba, hold my beer while I do this . . . "
     
    Last edited: Sep 13, 2014
  6. odie

    odie

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    I appreciate your thoughts, Mark......

    We all have to do what we feel is in our best interests......and, it's better to act on those thoughts, than to speculate that they won't help, and end up not making any attempt to solve problems.

    I'm not saying you're wrong at all.......but, it is my opinion that my latest attempt to improve my safety prospects is a success. Certainly, I do agree there could be an incident where the riot shield won't help at all, and I still could be seriously injured, or dead!......However, I do feel that particular outcome has been reduced in overall possibility.

    edit: I should add here, that if there is any reasonable doubt of a failure of any particular piece of wood, I'll be wearing my modified fielder's mask under the usual face shield......which would greatly increase the safety aspect. If there is any injury from wood separation, or failure in my future, it will be a piece of wood that gives no outward indication that it will. I acknowledge that it's entirely within reason to assume that time may come, and I am doing what I can to help protect myself. Staying our of the "line of fire" is all well and good. I practice that whenever I can, but since it limits your body movements and positioning of lathe tools, it's unreasonable to expect most, if not darn near every single turner to cross that line from time to time.....even from those who say they don't......they just don't admit it. Even so, the rule doesn't apply to ricochets.....as we've heard some examples of that very thing. If someone wants perfection in safety expectations all the time, every time.....he should consider some other endeavor than wood turning.

    ooc
     
    Last edited: Sep 13, 2014
  7. hockenbery

    hockenbery AAW Advisor Staff Member

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    Mark,

    Sort of the whole point. We "never" intend to forget the basics. Most of us being human have done one or two really stupid things in our lives and we "never" know when the next one will be accomplished.

    Our ability to detect hidden flaws in wood is imperfect at best. The separation of a large blank is a huge risk we take when turning large pieces.

    As to risk management.....
    It is what we do in virtually every aspect of safety. Whether it is buckling seat belts or going inside during thunder storms.

    The USA used to average 80 deaths a year from lightning. We now average 30. Everyone knew it was a good thing to come in out of the rain but few people did it.
    Using risk management tools of mandating the stoppage of work and emptying stadiums when lightning hits within 6 miles and waiting 30 minutes after the last detected lightning strike to resume forces people indoors. Imagine the cumulative time, effort, dollars spent to save 50 lives a year! 62.5% is a failing grade!
    It's amazing how much we Americans value life when it comes to lightning deaths.

    Page 27 of the June 2014 American Woodturner has an excellent article by Lynne Yamaguchi.
    She has some energy calculations for flying wood and the energy absorbing ratings of different helmet standards.

    Sort of the bottom line is that even a riot helmet would not have been rated to withstand the force with which Lynn was hit but it was close.

    Al
     
    Last edited: Sep 13, 2014
  8. hockenbery

    hockenbery AAW Advisor Staff Member

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    In the article, Lynne Yamaguchi refers us to a chart on the AAW web site.

    It provides the standards for various shields and the kinetic energy of sample woodturning projectiles.

    http://c.ymcdn.com/sites/www.woodtu...Yamaguchi.pdf?hhSearchTerms="Assess+and+risk"

    Keep in mind the charts refer to impact. With a large block hitting the head the concussion and brain injury are events that can happen even though the face isn't damaged.
     
    Last edited: Sep 13, 2014
  9. hockenbery

    hockenbery AAW Advisor Staff Member

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    Odie,

    What are the specs on your shield

    Lynne's article discussed the NIJ 0104.02 standard for impact resistance.

    There is a huge difference in the z87 + High" standard which the bionic shield meets and the NIJ 0104.02 Standard for riot Face shields.
    Something like 4.4 joules and 111 joules.

    If you got a NIJ 0104.02 rated shield for $15 that is a bargain.
    Al
     
  10. Mark Mandell

    Mark Mandell

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    Lets also remember that Lynne's article and test value was for a US riot HELMET, not just the face shield as Odie is using. The helmet would be supplying a substantial amount of structure and protection that Odie's modified flip-up will not have. If somebody wants the protective capacity noted in Lynne's article, they have to buy the whole rig, helmet, face-piece, (chin straps and suspension system) and all.
     
  11. Mark Mandell

    Mark Mandell

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    That's fine Odie. You are absolutely free to make your own choices. But just be careful how you express your "opinions" here as they may lead some of our readers on the forum to give them more weight than they should. I rather doubt you'd enjoy hearing from somebody's widow about how her husband followed your "advice" and made the same rig, but was killed when hit by flying lathe debris. "But I was only sharing my OPINION about my modified shield. I wasn't encouraging others to do the same thing," will be cold comfort, indeed.
     
  12. odie

    odie

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    I almost feel like playing a tune on my violin for you, Mark! :D

    We are all grown-ups here, and being so, make our decisions based on what we feel is best. I shouldn't have to remind you that not one single time did I suggest anyone else modify, or experiment with anything I have done (....and there have been many discussions like this one.). I have given a description of what I have done, that's all. I discuss, listen to input, and contemplate, just as everyone else does. I make my decisions based on my own conclusions and speculations, and act accordingly, which includes taking responsibility for my own actions......and I expect everyone else to do the same.

    ooc
     
  13. odie

    odie

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    By the way......and addressing positive discussion again.........

    I am back in from about 7-8 hours out in the shop today. I wore that riot face shield for most of that time. As I said previously, it's noticeably heavier than the original configuration. (With less protection, IMHO.) I do miss the lightness of the old face shield. I can probably get used to this over time, but I still may decide to get a bionic face shield eventually. ;)

    ooc
     
  14. odie

    odie

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    I don't know, Al.......there was no paperwork with the riot shield. If the military contract was as these things have been in the past, then the shield is probably very good quality. It certainly does have the feel and heft to it that makes me think there probably was no cutting corners in making it.

    ooc
     
  15. stu senator

    stu senator

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    Helmet and shield design

    A facemask is designed to stop a projectile from directly hitting the face or head but it just transfers the energy to your head which absorbs the energy and rattles your brain around.

    What is needed is a method of stopping the projectile before it hits the shield, but the only example I have seen is on display models of lathes, never on one being used in a shop.

    For the face shield there should be a system of attachment to the head that is solid, easily removable, comfortable and most importantly that spreads the energy (as yet undefined) of the hit over a period of time rather then the almost instantaneous time of the hit.

    The head band of the shields such as Uvex mask I have seen and used are almost worthless for this last requirement. See a prior post of mine is this thread.

    A baseball weighs 5.25 oz (0.149kg) and is 3” (76.2mm) in diameter and a hockey puck weighs 6oz (0.17kg) and is 1” (25.4mm) thick by 3” (76.2mm) diameter

    Both have been measured at 100mph (44.7 meters per second).

    Using E=1/2 m*v (squared) this gives an energy of 0.5*0.17*44.7*44.7=170 Joules for the puck.

    This is greater then a riot helmet shield specification. I did not find a hockey or baseball specification on a quick look at Google.

    A Catcher's mask: ( From Wikipedia) (To protect the face, much of the side of the head, and, often, part of the throat. In recent years, catchers have begun wearing masks similar to those worn by ice-hockey goaltenders. The hockey-style mask typically includes a section which protects the top of the head…

    Since the catcher and goaltenders mask have to stop a well defined size and shape projectile they can be wire cages. As woodturners we never know the size, shape or even the weight or maximum velocity of the projectile. Some guesses after the fact are available. See Lynne Yamaguchi writings.

    The idea of mating a riot shield to a hockey or catchers mask per Odie is not so far fetched an idea as it is made out to seem. The problem is a method of attachment that allows the full force of the blow to be transmitted thru the padding to the head without failure.

    This would be a specialty item with minimum demand as most of us would not want to take that perfect cut that puts us in harms way.

    Stu

    If you Google Ballistic Helmets specifications to see what is offered in helmets or look at NIJ Standard for Ballistic Helmets - National Criminal Justice ...at

    https://www.google.com/url?sa=t&rct...hxgTGxUV55MeIog&bvm=bv.75097201,d.cWc&cad=rja

    you will see a basic method of testing, not an actual spec.
     
    Last edited: Sep 15, 2014
  16. Mark Mandell

    Mark Mandell

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    Stu,

    I questioned Odie's experiment because he was NOT attaching the riot shield to a helmet, but rather to the flimsy headband of the generic flip-up in common use. Lynn's article made it pretty clear that the helmet, as part of a system was required. Protecting turners is not about small-point penetration of the plastic, but rather deformation and impact on the face and head of the shield and the flying wood. As I mentioned before, I doubt any "head gear" will protect us from an impact. Transfer the energy to the head and we'll be dealing with concussions, cerebral hemorrhages, sub-dural issues, and spinal cord injuries. A safety cage like that on the PM, albeit redesigned, is more likely to prevent the impact entirely.
     
  17. stu senator

    stu senator

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    Mark

    I said he was on the right track and the shield SHOULD BE ATTACHED TO THE FACE MASK SECURLY.

    I agree the the shield should be on the lathe but have to see anyone use one where available.

    Stu
     
  18. hockenbery

    hockenbery AAW Advisor Staff Member

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    Check lit page 27 of the June AAW journal.

    Lathe shields are seldom used. They certainly put a barrier between the wood and other turner.
     
  19. odie

    odie

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    Hello Stu.......

    The military attachment is very secure. I cannot remove it without using a lever to open the spring clips to install/uninstall. It appears as though a leverage point was the intent of the holes. It is as secure as if it were attached to the Kevlar helmet. Now, if the force were reversed, maybe it could be dislodged, but as it is, any blow from the outside toward the face is not relying on the spring clips for secure attachment.

    Yes, Mark......the helmet would probably provide additional support, but I'm seeing this modification not from a comparison to the full helmet/riot shield......but from the standpoint that the setup I have is an improvement in protection over the original face shield. That objective appears to have been accomplished.

    ooc
     
    Last edited: Sep 15, 2014
  20. odie

    odie

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    Hello again, Stu.......

    The idea was to improve the protection provided by a regular face shield, and I think the addition of the riot shield does that......but, it's not perfect protection, just an improvement.

    At times, I will be using my modified fielder's mask under the riot shield mounted to standard headgear. This provides excellent protection, as any solid hit will transfer the blow to the riot shield, and then the fielder's mask. The fielder's mask is similar to a catcher's mask, in that it has a padded chin piece, as well as a padded support across the top of the forehead. It is not my intention to wear the fielder's mask all the time, but I will when I feel the need is greater than normal. During those times, it matters not if you are out of the "line of fire", because there is no real complete safe place to be. As I previously stated, I do stay out of the way most of the time, but there are times when I don't because the results I'm intending to get require some gamble in the process. (For Mark's sake, I am not suggesting anyone else do what I do......I'm merely stating that I feel the quality of the cut and profile of the form can't be had without perfect positioning of the tool combined with complete freedom of body movement.)

    ooc
     
    Last edited: Sep 15, 2014

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