Head and face protection

[David Delo]

Richard,I heard Stuart Batty say once, 1,000 rpm's an up and it goes airborne and under 1,000 rpm's it goes to the floor. Must agree that 20" bowl at 1,000 rpm's is much to fast for that size piece. Don't know your turning skill level but it would be nice if you could tape whatever pieces you have left and post a picture of the bottom of the bowl to see the recess. You could get plenty of help here at SMC to determine if maybe the size, depth, recess angle or how the piece was seated in the jaws were correct for that particular piece. Perhaps one or more of those variables could be the root cause of the failure or maybe it was just a bum piece of timber to begin with. Having good headgear is very important but IMHO there isn't much out there that's going to do much against the size piece you describe for a full frontal direct impact. Get to the root cause first.Dave

[Doug Hepler]

All,

Very informative and attention-grabbing thread. The graphs of RPM vs diameter are now posted over my lathe.

Doug

[John K Jordan]

I never hear of turners use the steel mesh style face shields that loggers use. Do they cut down on sight too much? What is the impact resistance compared to the polycarbonate shields.

Do you mean this style?

helmet2.jpg

If so, I have several of these (Stihl brand) and besides the hard hat they seem relatively flimsy. They will stop chips from the chain saw and keep a small branch from whacking you in the face but wouldn't deflect a hard impact directly from the front. It might hang up a moving chain before it cut your face off but I haven't tested that. The instructions say to always use them with safety glasses - flying sawdust can come through the mesh. The built-in hearing protectors are nice. The hard hat did deflect a falling branch once for me.

I won't chain saw without wearing one of theses. Having the hard hat, face shield, and hearing protectors in one package is a big advantage. I use one when weed-whacking too.

JKJ

[Thomas Canfield]

I tend to agree with the general range of rpm vs diameter and will exceed it slightly on special occasions, but not over double. Additionally, I like to use a live center (even with wood block pad) and tailstock to help hold a large piece in the chuck when turning the outer regions until it has to be removed to turn the smaller diameter inside part. I also like to always have my cutting force directed toward the center of piece and not outward to pull the piece out of the chuck -DAMHIK.

[Richard Demler]

OK,I started with a 20in piece to turn..At the time of lift off it was actually 14 1/2 in in diameter..The grain was running across the bowl and it separated right at the edge of the chuck jaws..I'm sure the force of the jaws speading outwards and the grain running the way it was had A LOT to do with it taking off..There was no catch on the bowl and that is why I did'nt feel one..I think the centrifical force just blew the bowl apart..I have only been turning for a year or so lately...Someone asked if I if I was feeble or something LOL Nope far from it..58 truck driver healthy so far..

[Reed Gray]

The force of the chuck jaws can make a difference, but most of the time, if it fails, it is a combination of too small of a shoulder, too much tightening, and a catch. If you add in a defect in the wood, that will also contribute. If there is any discoloration in the line where it broke, that is the cause. If there was any end checking in the piece before you started turning it, that can mean invisible cracks that you can't see. When in doubt, before turning up the speed, I rotate by hand first and feel the rim to see if I can detect cracks. I also will some times thump it with my fingers. Dull thump means crack, a ringing tone means solid. It's the ones you can't see that get you....

robo hippy

[paul cottingham]

Land line for sure in a shop. I have health issues and the fellow I do most of my woodworking with has significant ones. His shop is stand alone. We are putting a landline (hardwire) phone in his shop. I can do the wiring so it not an expense for him but the next time he needs an ambulance isn't going to be the one time his batteries are dead, if I can help it.

I should think any shop with a lathe in it should have a land line in it. That way you can always call for help, and if you drop the phone, they can always trace it.

[Steve Mathews]

This is one thread that has received more than my full attention. I am rethinking all of the safety equipment, practices, etc. garnered so far. Thanks all for the discussion, and especially Ms. Yamaguchi for the excellent article describing her frightening experience.

[John K Jordan]

...I also like to always have my cutting force directed toward the center of piece and not outward to pull the piece out of the chuck.

I know an older gentleman who might benefit from your class on mounting for turning. I watched (or heard) him throw the same bowl out of the lathe maybe four times and the same hollow form several times as well. I would hear a noise then an expletive. Several of us tried to help but it wasn't taking. I think tool control and big catches were a factor. Fortunately, there was no need for an ambulance. I wondered belatedly if he simply lacked the strength to tighten the chuck properly since he did have medical issues.

Doc Green has some interesting articles on keeping things in the chuck.
http://www.docgreenwoodturner.com/holdingpower1.html
http://www.docgreenwoodturner.com/holdingpower2.html

For anyone not familiar with Doc, his articles are many and useful:
http://www.docgreenwoodturner.com/articles.html

JKJ

[Len Mullin]

I would think one of the main issues, was that you used a mortise rather than a tenon. I dislike using mortises, to begin with they put outward pressure on the blank which can make a situation worse. A tenon at least by its nature, doesn't cause any outward pressure on a possible crack.
Len

[Kyle Iwamoto]

Does anyone turn with their cage down? I usually try to. That should stop lots of potentially harmful occurences. I painted mine flat black, due to an article in the AAW magazine. That really helps looking past the cage at your work. In addition to the cage I also use a Bionic face shield, as well as safety glasses beneath. My $0.02 is to use the cage as a first step, as well as a face shield....... The small stuff goes right through the cage. All of that said, I don't use the cage when doing the final cuts, as the OP was seeming to do...... Glad to hear you were not injured.

[Dok Yager]

Great thread and especially the article Roger, Thanks for the link!

My neighbor took a very hard shot two years ago from a piece of purpleheart that Exploded and caught him in the face mask and hand. His hand was Badly bruised for weeks and he had a minor fracture of one bone. The two pieces one of which went up and through his garage ceiling and into the attic. The other went to the opposite side of the garage. I had just left a couple of minutes before it happened. He didn`t turn for several weeks.

[Geoff Whaling]

"My question is what face-mask is strong enough to take a hit from something like that and still leave my face on the front of my head..????"

A. None!

I will qualify that -a good face shield rated to extra high impact protection will minimize injury by deflecting and transferring the impact forces, HOWEVER that may cause other injuries from the primary impact or a secondary impact with another item if the turner is knocked off their feet, neck injuries, Traumatic Brain Injury etc.

Safety at the lathe is a system! All turning processes, work holding methods and controls used to reduce hazards must match the hazards and potential consequences if things go wrong.

Time to appraise what went wrong, why the bowl split, why it went airborne, and why you escaped injury this time. Many lessons to be learned from such an event as the event is usually not caused by one error or fault in isolation.

Generally many things contribute to the event, one possible scenario - constantly tightening the chuck (stressing the grain), insufficient wood around the internal recess to resist the chuck expansion forces, a minor fault in the blank, too high lathe spindle speed, forces the bowl blank to crack go out of round then either self destruct or cause a minor catch that is the last straw in the whole chain of causes.

Best thing is you get the chance to change your underwear, and the opportunity to assess what happened, and hopefully not make the same mistakes again.

Ps I corresponded with Lynne Yammaguchi a fair bit prior to her presentation at the AAW Symposium a couple of years back. Her blog is a must read for any wood turner. It can all go pear shaped very very quickly as Lynne's experience highlights.