a Platter ???

[nine fingers]

I had this solid piece of camphor laurel, no cracks or flaws, 420 mm diam x 50.mm
Just the right size for a platter. Spent about 2 .5 hours up until the final sanding, about 5mins from finishing , kerrrr bang , never had anything disintergrate on the lathe before. As you can see by the pics the outcome,the larger bit collected me on the fore arm , no a cut , a gouge the thickness of the platter,about 6mm, quite a few stiches to pull the flesh back together.
I think its safer to make jewellery boxes. nine fingers.

[weisyboy]

there is a peice mising. find it, get out teh super glue and stop beign a baby:U

[Ozkaban]

Wow, what a shock:o

You're right, Lathe's can be dangerous. Just be glad you're not eight fingers now :;

Still, it looks as if it would have been a nice platter!

Cheers,
Dave

[Tim the Timber Turner]

I may be wrong but I suspect you were holding it in a chuck in the expansion mode.

If this was the case when the platter gets thin, either by cutting or sanding,
the pressure from the jaws is more than the timber can sustain.

Result = KERRR BANG.:~

Much safer to hold by contracting the jaws onto the foot. This tends to hold the wood togerther. :2tsup: With care, pieces with splits can be worked using this method..

There again I could be wrong :C in which case I'll get back up my tree.

Cheers

Tim

[rsser]

Pity. Nice looking piece.

Yes, Tim's point is worth checking next time. Mount the piece and grab either side and wiggle. You only need it a bit tighter than the barely moving setting if you've made sure the dovetail angles match.

It's also possible that there was a fine crack in there. Some you can't see short of bending a thin cross section slice.

[mkypenturner]

pity about the platter damn they go off like a bomb you are lucky its only a few stiches could have worse :stars::1eye: THIS IS A REMINDER TO ALL OF US TO TAKE CARE

[orificiam]

It looks like it would've been a beautiful plater.:((:(( but you can't give up now.
Looking at the dovetail it looks like it may be tapering the wrong way.Of cause I've been wrong before.
now back on the horse.
Cheers Tony.

[dai sensei]

Ouch :o

[nine fingers]

there is a peice mising. find it, get out teh super glue and stop beign a baby:U

Hi Weisyboy, They were the two biggest bits, I found another 12 mixed up with the shavings ,your quite welcome to them to reglue together.
To another member I was holding it in compression mode on a 60mm diam x 12 mm , which I intended to remove by hand after all sanding was completed
regards nine fingers.

[Grumpy John]

All might be lost, check out this (http://www.woodworkforums.ubeaut.com.au/showthread.php?t=92774) thread.

[robutacion]

Gees...nine fingers...!:o:C

Stuff the timber, your arm is a lot more important. Hope that you are recovering well!

I can be wrong, but I thing the problem wasn't the way it was mounted, but a fine crack that has develop with the grain while you were finishing it. It could have happen when you so well, gave it a very thin and even thickness all through, maybe just a little too much for its diameter. The sanding process is perfectly capable to cause such a fault, as the force and heat resulting from it is well known to create separation of a weak point in the timber. Vibrations on such large & thin plates/platters are also to consider, not that you can see the piece wobble, but the point where the contact is made with the sander or hand, throws the balance out, creating an invisible vibration that can "rip" apart thin timbers.

Anyway, with some luck, you will trying to make another soon, right?:D

Cheers:2tsup:
RBTCO

[Ed Reiss]

Now you have an opportunity to frame the pieces and title it "My Most Expensive Platter" :doh:

Glad you weren't hurt more !!!!

[LogDog]

Well, you could have become 5 fingers:doh: Lucky you did not.
We may have all been calling it killer Camphor.:;
I wonder if it is not a species thing. I believe camphorlaurel is not the most stable timber around and the heat from sanding may well have caused the camphor oils to expand and create further instabilities. Maybe it was not fully seasoned which could give anyone grief especially with camphorlaurel. If Camphor seasons too fast it moves like the ocean and if it has been a fast growing tree it will move more freely as it looses it's moisture, which will present as weak points and fractures as the cells stress and disassociate. Seasoning these timbers is so critically important and that is why it pays to know your sources well.:q

[Farnk]

Mate!

There's a bit missing!
Do us a favour, go have a squiz in the mirror, you might find it!:D

Seriously tho, thanks for telling us your story, this is a lesson to us all!

[Tim the Timber Turner]

was holding it in compression mode on a 60mm diam x 12 mm , which I intended to remove by hand after all sanding was completed
regards nine fingers.


My first guess was wrong so I’ve come down from my tree to make some more observations.

A 420mm platter on a 60 mm spigot is problematic at best.

Having said that, the platter survived the tool work and only disintegrated while sanding.

I was sorry to hear that you needed some medical treatment for your wounds.

I would humbly suggest the spigot size should be a minimum of 100mm for a piece this size.

Personally I would use a foot size of 140mm on a piece this size and hold in the contraction mode.

I have a couple more observations.

1: The maximum holding strength of a chuck in contraction mode is when the jaws are open about 3mm. At this setting the jaws form a perfect circle and there is maximum wood to metal contact. Another benefit of this is no marking of the foot in most timbers.

2: The depth of the spigot should be a touch short of the depth of the jaws. This enables contact between the face of the jaws and the bottom of the platter. Using this method if you have a catch most time the piece will move in the jaws but not depart from the lathe.

3: If the foot is longer than the depth of the jaws and bottoms out in the chuck, any pressure on the large diameter near the rim can result in the foot levering against the base of the jaws. This usually results in the piece departing to other parts of the workshop.

So having said all that, I would be interested to know what was the lathe speed when this happened?

In finishing I’m going to repeat my opening statement.

A 420mm platter on a 60 mm spigot is problematic at best.

I’m now going back up my tree and will wait to see if there is any incoming.

Cheers

Tim

[TTIT]

Geeeez John!:o Hope you treat that Belyando Blackwood with a bit more respect than the camphor :;:U.
An incident like this really brings home the benefits of vacuum chucks :2tsup:

[imdusty]

I'm blad to see you still have all 9 of your fingers! Keep up the good work!

[nine fingers]

Tim the Timber Turner.
In reply to your queries, lathe speed was about 1500 rpm, the spigot remained in the chuck, I have come to the conclusion that the platter seperated from the spigot when I was applying sanding pressure on the rim. :doh:
Lesson learnt:-, big platter bigger spigot.
john.

[ElizaLeahy]

WOW that's an education!!!

I'm glad that your arm is ok, it's only ornamental damange, nothing that will prevent you woodworking in the future!

Future? It's well wrapped, you should be able to get back to work now!!!

Going to make another platter now?

:)

[Skew ChiDAMN!!]

It's always a shocker when something gets through the abuse of cutting, only to fly apart while sanding! It looks like it would've been a nice piece when finished, too. :C

Fortunately, I've never been probed by UFOs... buzzed, yes, battered, yes but sampled, no. (And I hope things stay that way!)

[bobsreturn2003]

had a similar thing happen to me many years ago ,broke my wrist ! 300mm bowl with 75mm jaws contracting to hold and about 800 revs . was walking past with a scraper,when it blew up into 4 pieces . yeah should have shut it off , but one scrape ! and it was ready to sand . i have moved switch on lathe . and look very carefully at blanks , even tap some of them . must have been some residual stress , possibly relieved when i turned it . it was still green . still love my turning , but try and keep out of the flight path . cheers bob