Serious Bowl turning injury

[Roger Chandler]

Cindy Drozda reports a bad lathe accident over on WOW. Herman DeVries posts a facebook link in the thread. I don't have a facebook account, so I cannot personally access it, but others may want to take a look. Safety at the lathe is so important!

https://www.facebook.com/photo.php?fbid=258247107977968&set=gm.480212468976882&type=3&theater

[daryl moses]

Link doesn't work for me.

[Brian Kent]

I also have not been able to access it. How serious was it?

[Roger Chandler]

The only thing I know is that it was a serious head injury, and some talk of the turner using a recess for a large bowl, and high rpm's. Members of wow can see the thread for themselves,. Someone mentioned a pic, but I have not seen any of it due to not being a facebook member. Perhaps someone with ability to access the info can report back here.

[Bob Bergstrom]

This was recently on Facebook. It said he was wearing a face shield and was recovering in ICU.

[Roger Chandler]

That is bad! Thanks for posting Bob!

[Reed Gray]

It was commented on at our club meeting tonight. He was supposedly wearing a face shield. Don't know if he was in line of fire or not.

robo hippy

[Grant Wilkinson]

Here is some text from WOWS. I understand that this is taken from the facebook post, so I hope it's OK to copy here.

"He was using a vicmark chuck, and had it internally chucked. It was a big piece of walnut, about 16" wide, 6" high and 3/4" thick at the rim, almost 1 1/2" at the base. He was done carving the bowl and was power sanding the outside, going at a high rate of speed. The bowl split in two and several chunks came off. Not sure the size of the chunk that hit him. It shattered the window behind the lathe.

He was using a Uvex shield and there is a piece of the frame missing at the forehead. The frame is completely split."

[Stan Calow]

Another non-Facebook user. Can someone summarize how this could have been prevented?

[Roger Chandler]

Another non-Facebook user. Can someone summarize how this could have been prevented?

Using a tenon for larger, heavier blanks is a better hold [usually] than a recess. Power sanding at high lathe speed can put side pressure on the outside of the form acting as a lever to pry the piece off the jaws. Inspecting the wood carefully for cracks, etc is important. Power sanding can generate heat, and produce cracking in the wood, so stopping often to inspect can help identify what is happening to the wood as you go to each grit.

Use light pressure when sanding, and use jaws with a mechanical hold [either dovetail or serrated]. Sanding is more effective when the lathe is at low rpm's.

[Mike Goetzke]

Using a tenon for larger, heavier blanks is a better hold [usually] than a recess. Power sanding at high lathe speed can put side pressure on the outside of the form acting as a lever to pry the piece off the jaws. Inspecting the wood carefully for cracks, etc is important. Power sanding can generate heat, and produce cracking in the wood, so stopping often to inspect can help identify what is happening to the wood as you go to each grit.

Use light pressure when sanding, and use jaws with a mechanical hold [either dovetail or serrated]. Sanding is more effective when the lathe is at low rpm's.

This is what I have been taught - wonder what RPM he was at?

[David Sloan]

I had not hear of this so thanks for bringing it to our attention.I have been hit hard once in the faceshield and it was frightening. It is always good to be reminded of safe woodturning practices and I hope this fellow turner makes a complete recovery.

[David Bassett]

Another non-Facebook user. Can someone summarize how this could have been prevented?

I don't know about this specific accident, but Lynne Yamaguchi Blog'd about a serious accident she suffered and the research she did into turning safety:

http://lynneyamaguchi.com/index.php/category/accident-recovery/

If you dig into her posts, you can find a couple PDFs with articles and analysis she did on turning. (Short story: masks are for keeping tiny bits out of your eyes and face, not for impacts from chunks with serious mass.)

[Bob Bergstrom]

It certainly appears that a sharp edge of the broken portion of the bowl sliced up his forehard or possibly a section of his broken face shield. That is a long laceration for a blunt object impact. Something spinning up his head or being forced by a trailing object. That's a lot of staples.

[paul cottingham]

Bob, it could also be that they needed to do brain surgery on him. That would explain the number of staples. Every time they open up my head (I'm at 6 times, I think), I'm surprised at the number of staples it requires.

[Leo Van Der Loo]

Another non-Facebook user. Can someone summarize how this could have been prevented?

Very easily, make sure there is/are NO splits in the wood and slow down the lathe speed, high speed is the danger that time and again strikes out and causes havoc even killing turners.

It seems to be hard for turners to take a good look before starting an a piece of wood

Here is a picture of a piece of wood that had pieces splitting off of it 3 times, and the turner was lucky to not get that against his noggin or he might not be turning still, you better have a close look at the wood you want to turn and not just go at it.

360948


Lynne Yamaguchi got nearly killed for the same reason, here is the picture of the piece that split off, where you can clearly see where the wood had a split and another one in there also.

360949

[Kyle Iwamoto]

Another non-Facebook user. Can someone summarize how this could have been prevented?

Turn with your cage down? I think I'm 1 of 2 persons that does use the cage. That being said, I almost never use it while sanding. Although, I sand 500 RPM or less. The other cage user is a friend of mine.

[Thom Sturgill]

Nova generally rates the expansion mode as stronger than compression. That said, the fact that the bowl split would make how it was held immaterial. Rotational speed and internal weakness of the wood are the apparent key factors. Hope he will be OK, that would appear to be a very serious injury with possible brain injury.

[Joe Frank Porter]

In regard to expansion or compression, I have had several pieces come off in the compression mode and maybe one off of the expansion in the recess. I have often wondered why so many use the compressed tenon when I have had problems with compression. I use a Super Nova 2 chuck with the 100MM jaws and the 75mm jaws.

[Bill Boehme]

Nova generally rates the expansion mode as stronger than compression....

Whatever they might mean by that if it is an accurate quote, they can only specify the characters of their chucks and not the wood.

I'm not very trusting of using a mortise grip on a piece of wood. A tenon is held on all sides by steel jaws. A mortise is held by steel jaws on just one side which is trying to pry the wood apart ... wood and air are the only things pushing back. :D

[Jeramie Johnson]

Ouch, I agree, impact required internal surgery more than likely. Hopefully he comes out all right.

High RPMs and sanding, that works more against you, than for you.

[Leo Van Der Loo]

Whatever they might mean by that if it is an accurate quote, they can only specify the characters of their chucks and not the wood.

I'm not very trusting of using a mortise grip on a piece of wood. A tenon is held on all sides by steel jaws. A mortise is held by steel jaws on just one side which is trying to pry the wood apart ... wood and air are the only things pushing back. :D

I do not agree with you on that Bill, all you do is relying on the strength of the wood in it’s bonding to itself, where some will separate easier than others.

With a tenon it is this small stub you are squeezing and hope it will not be pried off of the rest of the bowl, it doesn’t matter how tight you can squeeze that stub, as that will stay right there if the bowl is pried away.

With a recess you rely on the same, but with a much larger area to support the forces that are pulling on the hold of the jaws on the wood.

Can you over tighten ?, yes of course, and I would say in both cases this can be done, you could start to split the wood by squeezing the stub as well as expand too hard on a weak wood or shape.

I personally have turned a few thousand bowls, and the greater majority have a recess to hold the piece after they are rough turned initially, I do not remember a single time that I split a bowl by expansion, lost maybe one or two with the tenon separating of the piece, and I feel much safer holding the large bowls as well as the smaller ones with a proper recess, YMMV ;)

Of course this has nothing to do with this case IMO it is like usually going TOO fast, and very likely a compromised piece of wood.

And as why someone is going to use high speed to sand is beyond me, a good way to heat up the wood and surface harden the wood, even starting small splits from the heat.

[Reed Gray]

The argument for 'which is stronger the tenon or recess' will go on for ever, kind of like the old Miller Beer commercial, "Less Filling/Tastes Great!" I have and will maintain that neither has any advantage as long as they are made properly. The only exception would be that I would never use a recess on end grain turnings.

One major teaching failure with woodturning is not letting turners know how important standing out of the line of fire is.... Number 1 line of defense.

robo hippy