Thread: Blackwood Platter Incident

A rough mental calculation indicates that the speed of the outer rim of the plate was around 7000 FPM using your original dimension of 1050 dia. That seems fast unless that is a hard, dense wood. Any catch at all could be dangerous.
It is great that no one was hurt.

A very worthwhile tale, well told. It's these learning experiences that make the forums more useful than just asking Q's and getting answers.

Someone once said 'Don't trust to luck, rely on it.'

I think you need to allow a little time for your 'Luck' quotient to build up again!

Just glad that you and everyone else in the building came out unscathed.

Hello HSS,
I tend toturn big bowls/platters and I appreciate your information. I have found (from experience) that turning at a slower speed until the block is in balance is the preferred safety position. I turn at about 350 - so at 250mm it is 3500 rpms, 500 - 7000. I tend to use a large glue chuck on the outboard or if inboard I use that chuck and bring up the tailstock for added support. To reverse I use the glue chuck, several sizes and attach to the turned foot etc. Having said all of that, sometimes wood factors come into play and maybe that was what happened in your case. I might add that for the glue chuck I use a good thick smear of hot glue on a heated chuck and then snap if cold with a frozen lump of steel that I keep in the old frig. The glue chuck is simply a large round of aluminium (130mm) tapped out and threaded to fit the spindle thread. Works very well with a packer to aid easier removal. Hope this helps a little. Please take my comments as constructive. Regards, John M.

What would of been more effective in your narrative would be a description of your feelings. Because as I read this I felt sick and nearly lost control of my bowels. Thanks for sharing though, your disclosure of this situation has made me think a litle harder on how I should be doing this kind of work at the lathe.

Wow!
I bet that had your heart thumping!

Thanks for sharing this with us HSS.

We all need to learn from these incidents and a post event analysis shared with everyone is an invaluable contribution to our collective well being.

I have only ever had one 'projectile' off the lathe. A gum vein parted letting a slice come off the the side of a deep bowl. I eventually found the shard up in the rafters with razor sharp edges that had done some damage on the way. Fortunately it missed me as I think it would have sliced through my face shield had it hit it. Lesson for me: Never use a blank with gum veins, there is enough other wood in the world to see me out.

I share the above because the slice coming off the side of the blank was slung away at very high speed, whereas intact blanks that come off tend to drop slowly while they continue to spin and only get going when they hit the deck.

There was probably still enough spin in the blank when it hit the galvo box and split up for the centrifugal forces to take over and fling the shards away as they did. Had the blank begun to split up as it left the chuck block that would also explain the projection distances.

What a relief that you have come out of the incidence unscathed (except the $s) and the wiser for it, John.

Blackwood is one of those timbers that move in the heat and maybe you got some minor internal checking. A bit of platter flex, high speed and too deep a cut for the circumstances?

Also, kiln-dried timbers appear to be more brittle than air-dried as far as I know.

The splintering of the wood in the pics might hold the answer, at least if that's how they were before the ricochets.

Good to see the Sapporo tonic in the pic.

Live to fight another day. Maybe get a motorbike helmet and chest armour ;-)

it's very dangerous

Lucky escape buddy!!
Does anyone know if there is a certain grade of perspex we should use in our face shields to protect against this type of thing??

This has only ever happened to me on smaller stuff, although my heart races for few minutes after!!!

Originally Posted by Dez Built

Lucky escape buddy!!
Does anyone know if there is a certain grade of perspex we should use in our face shields to protect against this type of thing??

This has only ever happened to me on smaller stuff, although my heart races for few minutes after!!!

You wouldn't want to use perspex, it'll shatter and slice your face. Polycarbonate is what you should be using, it's actually what they use for bullet proof glass.

As sjt said, Polycarbonate is what you need and make sure it is marked High Impact according to the AS/NZS 1337 Standard.

When a timber platter becomes a flying saucer!
One of the good things in life is to be blessed with a great mentor. As an apprentice I was so endowed.
Some 42 years later I still often hear his voice in the back of my head as I undertake yet another brainstrainer. A favourite of his was "wood talks to you" or "the wood will show you." We young fellas thought he had lost the plot. With time, I have come to understand what he meant. Once, we were visiting a mill, his comment to me was, "That saw doesnt sound happy." Next thing the blade disintergrated, with a large piece embedding itself into a post close to where we were standing. On another occasion, I had set up a large piece of forrest red gum on the lathe to turn a large wheel hub.
Old Ron came over and said," What did it say?" I said, "I dont know, it was too big and heavy to listen." He said, "The wood has spoken.....Start it slowly."

Good to know you and others were not injured.

A darn good write up and timely warning for all turners regardless of size. I'll be reviewing this often as a reminder.

Rusty Nail Old blokes know they have learnt or being taught well themselves. One such fellow with me always said "Follow your gut instincts, if in doubt DON'T"

Originally Posted by rsser

Blackwood is one of those timbers that move in the heat ...

Which is why I use it for firewood....it's only glorified wattle after all..