I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused
(I'm too wimpish to even think of it) or used wet. And I can't think why
age alone should matter with metal. But as I approached the paving
blocks I realised the cutting disc was 10 years old so an excess of
caution made me pause and ask. (Well, that and an excuse to put it off
in this weather.)



--
Robin
reply-to address is (intended to be) valid

On 24/07/18 14:36, Robin wrote:
I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused
(I'm too wimpish to even think of it) or used wet. And I can't think why
age alone should matter with metal. But as I approached the paving
blocks I realised the cutting disc was 10 years old so an excess of
caution made me pause and ask.Â* (Well, that and an excuse to put it off
in this weather.)





I've not heard of grit disks having a 'shelf life' but I can imagine
their 'aging' with use, due to vibration etc.

As for diamond disks, doesn't it depend on the construction?

Certainly, erring on the side of caution is wise, I've see an bench
grinder wheel shatter for no, obvious, reason. It could have be 'messy'.
Fortunately, it wasn't. (Other than the broken bits.)

In article ,
Robin wrote:
I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused
(I'm too wimpish to even think of it) or used wet. And I can't think why
age alone should matter with metal. But as I approached the paving
blocks I realised the cutting disc was 10 years old so an excess of
caution made me pause and ask. (Well, that and an excuse to put it off
in this weather.)

Worst that could happen is the diamond grit fall off. Unlike a fabric type
that might shatter.

--
*Virtual reality is its own reward*

Dave Plowman London SW
To e-mail, change noise into sound.

On 24/07/2018 15:33, Dave Plowman (News) wrote:
In article ,
Robin wrote:
I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused
(I'm too wimpish to even think of it) or used wet. And I can't think why
age alone should matter with metal. But as I approached the paving
blocks I realised the cutting disc was 10 years old so an excess of
caution made me pause and ask. (Well, that and an excuse to put it off
in this weather.)

Worst that could happen is the diamond grit fall off. Unlike a fabric type
that might shatter.

+1, can't see any risk if you are wearing gloves and eye protection.

Presumably this is a metal disk?

On Tue, 24 Jul 2018 14:36:02 +0100, Robin wrote:

I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused
(I'm too wimpish to even think of it) or used wet. And I can't think why
age alone should matter with metal. But as I approached the paving
blocks I realised the cutting disc was 10 years old so an excess of
caution made me pause and ask. (Well, that and an excuse to put it off
in this weather.)

Look at the use-by date which should be somewhere around the mounting
hole. The dates are very conservative (3 years from manufacture
generally).
It isnt all metal, there will be some time of adhesive holding the
diamonds in place.(though some are pressed into place). The danger is a
piece flying off and hitting you in the eye. Wear the correct goggles,
not glasses.

On Tue, 24 Jul 2018 14:36:02 +0100
Robin wrote:

I know grit disks have a limited life but is there a significant risk
with old diamond disks?

AIUI moisture, freezing and impacts can be problems for abrasive disks
that consist mostly of grit and glue. Those shouldn't pose a problem
for a mostly metal disk (other than affecting the adhesive that bonds
the grit, and I think they're usually brazed not glued anyway).
Suitable PPE should of course be used, I'd suggest a helmet and visor
rather than (or in addition to) goggles when using any large-diameter
fast-spinning thing that could throw chunks at you.

On 24/07/2018 14:36, Robin wrote:
I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused
(I'm too wimpish to even think of it) or used wet. And I can't think why
age alone should matter with metal. But as I approached the paving
blocks I realised the cutting disc was 10 years old so an excess of
caution made me pause and ask.Â* (Well, that and an excuse to put it off
in this weather.)

A metal disc should be fine. The better ones have the diamond fragments
embedded in the metal of the rim, rather than just being stuck to the
surface. So it should not wear any quicker.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 24/07/2018 21:22, John Rumm wrote:
On 24/07/2018 14:36, Robin wrote:
I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused
(I'm too wimpish to even think of it) or used wet. And I can't think
why age alone should matter with metal. But as I approached the paving
blocks I realised the cutting disc was 10 years old so an excess of
caution made me pause and ask.Â* (Well, that and an excuse to put it
off in this weather.)

A metal disc should be fine. The better ones have the diamond fragments
embedded in the metal of the rim, rather than just being stuck to the
surface. So it should not wear any quicker.



Thanks for that and to all the others for their comments. I omitted to
mention that it's a segmented disc so I was unsure if more than just
dust might come flying off at - if me sums are right(ish) - up to 300
mph. Anyhow, I'll add helmet and visor to the usual google and gloves
and see how far I get before I melt.


--
Robin
reply-to address is (intended to be) valid

On Tue, 24 Jul 2018 21:58:00 +0100, Robin wrote:

Anyhow, I'll add helmet and visor to the usual google and gloves
and see how far I get before I melt.

I helps to remember that any disc can fly to bits, and to plan accordingly.
While the discs may not fly to bits all that often, this planning will also help
avoid permanently embedding bits of glowing metal in nearby glass and tiles, or
setting fire to anything. Not likely in cutting blocks -- but the amount of dust
can be impressive!

One can practice with thin Dremel cutoff wheels, which fragment easily at the
slightest provocation and come without a guard.


Thomas Prufer

Protect ones face and hands etc. I too have seen discs go, but its often as
likely with new as with old and if the design of the grinder is right most
bits that fly off should not be going toward you. Myself, I never use one
any more for obvious reasons!
Bloody noisy as well even either ear defenders.
Brian

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Note this Signature is meaningless.!
"Brian Reay" wrote in message
news
On 24/07/18 14:36, Robin wrote:
I know grit disks have a limited life but is there a significant risk
with old diamond disks?

My 9" one has loads of diamonds left on it. It has never been abused (I'm
too wimpish to even think of it) or used wet. And I can't think why age
alone should matter with metal. But as I approached the paving blocks I
realised the cutting disc was 10 years old so an excess of caution made
me pause and ask. (Well, that and an excuse to put it off in this
weather.)





I've not heard of grit disks having a 'shelf life' but I can imagine their
'aging' with use, due to vibration etc.

As for diamond disks, doesn't it depend on the construction?

Certainly, erring on the side of caution is wise, I've see an bench
grinder wheel shatter for no, obvious, reason. It could have be 'messy'.
Fortunately, it wasn't. (Other than the broken bits.)

In article ,
Thomas Prufer wrote:
I helps to remember that any disc can fly to bits, and to plan accordingly.
While the discs may not fly to bits all that often, this planning will also help
avoid permanently embedding bits of glowing metal in nearby glass and tiles, or
setting fire to anything. Not likely in cutting blocks -- but the amount of dust
can be impressive!

One can practice with thin Dremel cutoff wheels, which fragment easily at the
slightest provocation and come without a guard.

Diamond coated discs are a very different contruction. Basically a steel
wheel with embedded diamond powder. So far less likely to implode than a
fabric type.

--
*He who laughs last has just realised the joke.

Dave Plowman London SW
To e-mail, change noise into sound.

On Wednesday, 25 July 2018 07:13:49 UTC+1, Thomas Prufer wrote:
On Tue, 24 Jul 2018 21:58:00 +0100, Robin wrote:

Anyhow, I'll add helmet and visor to the usual google and gloves
and see how far I get before I melt.

I helps to remember that any disc can fly to bits, and to plan accordingly.

grit discs yes, but rather hard for a steel disc to fly apart. I suspect you'd need to spin it up to 50k rpm for that to happen, or hit it with a hammer as it spins.

NT

While the discs may not fly to bits all that often, this planning will also help
avoid permanently embedding bits of glowing metal in nearby glass and tiles, or
setting fire to anything. Not likely in cutting blocks -- but the amount of dust
can be impressive!

One can practice with thin Dremel cutoff wheels, which fragment easily at the
slightest provocation and come without a guard.


Thomas Prufer

"Dave Plowman (News)" Wrote in message:
In article ,
Thomas Prufer wrote:
I helps to remember that any disc can fly to bits, and to plan accordingly.
While the discs may not fly to bits all that often, this planning will also help
avoid permanently embedding bits of glowing metal in nearby glass and tiles, or
setting fire to anything. Not likely in cutting blocks -- but the amount of dust
can be impressive!

One can practice with thin Dremel cutoff wheels, which fragment easily at the
slightest provocation and come without a guard.

Diamond coated discs are a very different contruction. Basically a steel
wheel with embedded diamond powder. So far less likely to implode than a
fabric type.


Implode?!

Wouldn't be a safety issue it they really did that I suppose ;-)
--
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Tue, 24 Jul 2018 14:36:02 +0100, Robin wrote:

I know grit disks have a limited life but is there a significant risk
with old diamond disks?

I thought it was only the flexible angle grinder discs that had a
shelf life because the resin deteriorated, the sintered bench grinder
type do not suffer from this and steel diamond ones don't either.

Under the abrasive wheel regs the use by date should be stamped on the
hole reinforcing if required

AJH

On Wed, 25 Jul 2018 02:44:48 -0700 (PDT), wrote:

grit discs yes, but rather hard for a steel disc to fly apart. I suspect you'd need to spin it up to 50k rpm for that to happen, or hit it with a hammer as it spins.

I can imagine a segment of a segmented diamond disc flying off, and the whole
disc becoming unbalanced, the grinder vibrating wildy, and mayhem ensuing...

There's a scale: One end is using the grinder freehand without a guard, wearing
synthetic shorts, no shirt (but a tie), flip-flops, and your dreadlocks falling
into the cut line, all the while standing knee-deep in solvent-soaked rags
releasing flammable and intoxicating fumes. The other end is wearing full plate
armor with a jousting helmet, a diving mask, angle grinder bolted in a stand,
guard, new disc, and have an ambulance standing by...

There is a range somewhere in the middle where I'd feel comfortable:-) I'd use
the old disc -- but be wary of where bits could fly.

Also, you can always get a block splitter, and avoid all the above, and the
dust. (Won't work for everything, though.)

Apropos of mayhem: I'll take the opportunity to post this H&S video on
forklifts. It's in German, nevermind, just watch. (Warning: graphic detail!).

https://youtu.be/iCGgPuD6qFI



Thomas Prufer

On 25/07/2018 12:26, wrote:
On Tue, 24 Jul 2018 14:36:02 +0100, Robin wrote:

I know grit disks have a limited life but is there a significant risk
with old diamond disks?

I thought it was only the flexible angle grinder discs that had a
shelf life because the resin deteriorated, the sintered bench grinder
type do not suffer from this and steel diamond ones don't either.

Under the abrasive wheel regs the use by date should be stamped on the
hole reinforcing if required


Yes thanks. I'd found that there was a requirement for AFAICS all
_bonded_ discs to have a limited life. (As Alan indicated, max 3 years
from manufacture). I didn't know what to make of my failure to find a
requirement for non-bonded discs: one of the many things I don't trust
is my search ability.

--
Robin
reply-to address is (intended to be) valid

On Wednesday, 25 July 2018 13:23:19 UTC+1, Robin wrote:
On 25/07/2018 12:26, wrote:
On Tue, 24 Jul 2018 14:36:02 +0100, Robin wrote:

I know grit disks have a limited life but is there a significant risk
with old diamond disks?

I thought it was only the flexible angle grinder discs that had a
shelf life because the resin deteriorated, the sintered bench grinder
type do not suffer from this and steel diamond ones don't either.

Under the abrasive wheel regs the use by date should be stamped on the
hole reinforcing if required


Yes thanks. I'd found that there was a requirement for AFAICS all
_bonded_ discs to have a limited life. (As Alan indicated, max 3 years
from manufacture). I didn't know what to make of my failure to find a
requirement for non-bonded discs: one of the many things I don't trust
is my search ability.

Hmm. I don't think any of my grit discs are that young.


NT

On 25/07/2018 13:21, Thomas Prufer wrote:

Also, you can always get a block splitter, and avoid all the above, and the
dust.

Block splitters cost money - and are heavy. Hire's not cheap at the
snail's pace I work. And I am really just playing, having picked up
c.700 Priora blocks for £60 (plus a couple of sweaty days ferrying them
in a Focus through London traffic over umpteen traffic calming measures).


--
Robin
reply-to address is (intended to be) valid