But, what happens to a disc over time?? I would have thought they would be pretty inert. Never noticed any storage instructions either, or indeed dates, on mine (never actually checked, and they are stored in a cupboard in the garage)
http://www.youtube.com/watch?v=IthnhIZz71w
Dodgy out of date Clarke cutting disks.
The man obviously wasn't wearing gloves and how does the disc come into contact with the back of your hand. I've had them go from twisting them in the cut inadvertently and they usually end up 30 feet away. He says he was grinding where it clearly says cutting disc on the label. I have discs in the shed which are years old and still using them with no problems, he sounds like he's after a claim.
I think you have a good ''where there is a blame, there is a claim case'' my friend. If you can prove they were purchased from an
official clarke outlet you should be intitled to compensation of some sort.
Extremely lucky that wasn't your eye!
quote:
Originally posted by Peteff
The man obviously wasn't wearing gloves and how does the disc come into contact with the back of your hand. I've had them go from twisting them in the cut inadvertently and they usually end up 30 feet away. He says he was grinding where it clearly says cutting disc on the label. I have discs in the shed which are years old and still using them with no problems, he sounds like he's after a claim.
I agree with Pete, he keeps referring to them as "grinding discs" when they are obviously cutting discs. If you use them for grinding, they
can and do shatter quite easily.
[Edited on 11/9/11 by MikeRJ]
quote:
Originally posted by Toprivetguns
I think you have a good ''where there is a blame, there is a claim case'' my friend. If you can prove they were purchased from an official clarke outlet you should be intitled to compensation of some sort.
Extremely lucky that wasn't your eye!
Irrespective of whether he was using them as intended, the fact that the date had had a sticky label put over it to make it look newer than it was is concerning. Someone was passing off a disk as something that it wasn't.
Yep, looks naughty
But, what happens to a disc over time?? I would have thought they would be pretty inert. Never noticed any storage instructions either, or indeed
dates, on mine (never actually checked, and they are stored in a cupboard in the garage)
I have used discs that were well beyond the expiry date with no problems. Could just be a faulty batch of discs. As said protectve gloves could save a lot of injury.
The guy has a nasty injury, but it is a bit OTT to say that something illegal has definitely happended because an expiry date has been changed - there
is no law covering cutting disc expiry dates!
I see two possible scenarios:
1) A dodgy company has bought a job lot of out-of-date discs at a knock-down price, and just put stickers over the date to hide the issue. Almost
certainly fraud at best, and quite possibly various other far more serious offences if people are injured as a result.
2) Clarke manufacturered too many, had a lot of stock that went past it's expiry date, did some testing and found the discs to be pukka and
unaffected by age so extended the date. There is nothing wrong with this providing it is based on technical expertise and testing - they are the
people who set the date in the first place afterall.
If its (1) then the guy has a valid point and regardless of whether he used or misused the discs probably will get a claim paid out, although if he
was using them incorrectly he should count his blessings as the same thing would have happened with a perfect disc and he wouldn't have got
buttons.
If it's (2), then it seems more likely he was abusing the disc, as so many of us do, and the date thing is pure coincidence.
Either way, some lawyers are probably going to make some money...
i have never seen an expiry date on cutting or grinding discs,so why is the date there?
3rd possible scenario.....
The disc broke for whatever reason.
He prints his own date label and applies it to stir up some dung.
Or they could be cheap copies from China
I've just had a look at the ones I have and all three makes have a year
stamped on the inner steel ring.
I must confess I have never spotted this before.
The top one is an old half used one but I have no idea when I bought it.
I'll just chuck it in the bin to be on the safe side.
IMHO a grinder with a cutting disc should be held with two hands.
One on the grinder body and the other on the side handle.
The work should be clamped solid.
Holding the work in one hand and the grinder in the other is asking for trouble.
Cheers,
Paul G
Cutting disc dates
quote:
Originally posted by theconrodkid
i have never seen an expiry date on cutting or grinding discs,so why is the date there?
My dad and I have had some spectacular fails in all the years of using discs.
Dad had a wall he was cutting take the blade clean off the machine and fly away frisbee style
I had a blade blow up at 3am in the morning cutting a damaged burglar bar away to repair it.
The bar sprung loose and grabbed the blade shredding it all whilst standing on a ten foot steps.
Some choice words where said. Have a lot of respect for carbo blades and always take care when using them.
I hate using the big machine ! It's potential energy is huge.
Mac speedy and I cut a diff out of an axle and it wanted to blow it's self to shreds.
Always have the shield on and a glove or two
Usually the cutting edge gets rounded off and print on the back wears away almost immediately when used for cutting. On the disc that exploded there
is no sign of either the cutting edge having been rounded or any of the print wearing.
I agree ... looks like he was grinding, just as he said himself. He blew his chance of compensation with that video!
So what do I do with this?
And its a biggee!
discbad
Could have just been a input error/printing error which was then updated with stickers
quote:
Originally posted by ReMan
So what do I do with this?
And its a biggee!
discbad
Think I'm going to have too 
discbad2
Look like Chinese knock offs to me. From what you can make out on the vid', the discs are pretty thick and cupped at the center like a grinding
disc. Cutting discs discs are flatter and not that thick. So if thats correct and the printing is dodgy along with dodgy quality... =counterfit?
I've had a dodgy batch of cutting discs in the past but they didn't explode, just broke up from the edge like very rapid wear.
first thing to check is the speed of the disc
it should be greater (faster) than the speed of the machine if petrol driven (in case it runs out of petrol and speeds up)
equal to if its electric.
Next
Storage, discs are made from resins and must be kept dry, if they get damp, they will fail.
next
how the operator used the disc, using extreme force is not the method, this also can damage the disc.
i recon the cause is one or more of the above.
IC
Resin and rubber bonded abrasives have a shelf life. Both absorb moisture from the air and degrade over time. We have had problems at work in the past
with rubber bonded wheels, but these go in enclosed machines and just result in a broken wheel and no major damage.
Vitrified wheels dont have a shelf life and will keep indefinately. This is the sort of wheels you have on your bench grinder.
If the disc has expired bin it, unless the disc has not been in contact with a lot of moisture, water & stored correctly, and if you does this at
your own risk be it (im not recommending this!)
Expirey dates can be extended but its not wise and its very rare that its carried out. I believe this can only be done by the manufacturer but role of
thumb is to bin it, we were strongly advise NOT to sell OOD blades and had to destroy them.
I once had to do an "abrasive wheels" course for a hire company and have obviosly used a few in my time, i would say that cutting disc has
either been miss used or has not been stored correctly, also could be that the grinder/cutter rpm is to great for the disc and may other possible
answers. If your cutting metal why would you not use a staight blade or thin cut anyway? Why the offset cutting blade?
quote:
Originally posted by adithorp
Look like Chinese knock offs to me. From what you can make out on the vid', the discs are pretty thick and cupped at the center like a grinding disc. Cutting discs discs are flatter and not that thick. So if thats correct and the printing is dodgy along with dodgy quality... =counterfit?
I've had a dodgy batch of cutting discs in the past but they didn't explode, just broke up from the edge like very rapid wear.
My Norton 0.7mm discs are depressed centre, and probably the most resiliant cutting discs I have ever used.... done the whole floor in my Camaro with
one disc...
Discs/grinding wheels only break for 4 reasons:
Misuse
Incorrect mounting
Incorrect speed - usually too fast
Age - only on rubber or resin wheels though.
quote:
Originally posted by flak monkey
My Norton 0.7mm discs are depressed centre, and probably the most resiliant cutting discs I have ever used.... done the whole floor in my Camaro with one disc...
quote:
Originally posted by daviep
Looks like a bog standard depressed centre 3mm cutting disc to me, the super thin 1mm or 1.6mm only come in flat centre but 3mm discs can be flat or depressed.
Mine was bought from Machine mart in the last month
quote:
Originally posted by adithorp
quote:
Originally posted by daviep
Looks like a bog standard depressed centre 3mm cutting disc to me, the super thin 1mm or 1.6mm only come in flat centre but 3mm discs can be flat or depressed.
Could be, but look more like 5mm discs in the pack to me when he holds them up edge on. Yes, it says 3mm on the disc but if they are counterfiet then that could be. Don't think I've ever noticed what look like cracks around the hub on new discs, before like those have.
quote:
Originally posted by Benzine
quote:
Originally posted by flak monkey
My Norton 0.7mm discs are depressed centre, and probably the most resiliant cutting discs I have ever used.... done the whole floor in my Camaro with one disc...
Impressive! I use decent 0.75mm discs from my local welding shop and they, too, have depressed centres. I'll look into Norton though as the ones I use wear our rather quickly (and cost a bomb!)
quote:
Originally posted by flak monkey
Vitrified wheels dont have a shelf life and will keep indefinately. This is the sort of wheels you have on your bench grinder.
I'll check tomorrow with our grinding wheel rep, but I am pretty sure vit wheels are good indefinately if stored under normal conditions.
quote:
Originally posted by adithorp
Look like Chinese knock offs to me. From what you can make out on the vid', the discs are pretty thick and cupped at the center like a grinding disc. Cutting discs discs are flatter and not that thick. So if thats correct and the printing is dodgy along with dodgy quality... =counterfit?
I've had a dodgy batch of cutting discs in the past but they didn't explode, just broke up from the edge like very rapid wear.
From my own experience, it is reasonably common for a manufacturer to carry out due-diligence to extend the shelf life on an item, particularly when
prompted by an impending write-off.
It could easily be a 'legitimate' change in shelf life; one would therefore hope that the manufacturer would hold documentary evidence to
prove that the materials were adequately tested and safe to use.