These 4-1/2″ x 0.045″ aluminum oxide cut-off wheels are used in an angle grinder to cut metal, stainless steel, and similar materials.
The disc, shown above, has been very lightly used, and has plenty of life left in it. Or at least it had plenty of usable life.
This particular disc expired in 2015. You can see the expiration year stamped on the wheel, on the metal bit towards the center.
Cut-off wheels and grinding wheels should not be used past their expiration dates, and that’s if they’ve been properly stored and handled. Mishandling or storing discs in certain conditions might lead discs to be discarded earlier.
So what happens after cut-off and grinding wheels expire? I can’t speak about performance, but there is a greater risk of breakage, shattering, or other such catastrophic failure.
I believe that the expiration has more to do about the adhesives used to bind everything together.
Have you ever seen brittle glue failure? Maybe aged rubber bands that broke when stretched?
Many abrasive wheels seem expire 3 years after they’re manufactured. Does that mean that a wheel is guaranteed to fail the very next day, 3 years + 1 day after it’s made? No. Ignoring environmental and handling conditions, a day or two won’t make a difference. But the older a cut-off wheel or abrasive wheel, the greater the chance of catastrophic failure.
UV light, humidity, and temperature fluctuations are some of the favors that could degrade abrasive wheels’ bonding agents over time.
Different types of products might have different expiration times. I have seen bench grinder abrasive wheels with 2 year expiration dates.
ALWAYS wear proper safety gear when using abrasive wheels at any kind. They can and do break, and you need to follow experts’ safety recommendations, such as manufacturers’ and OSHA’s.
Abrasive wheels should also be inspected before each use. (Are there any other abrasive wheel safety checks that you know of?)
What would happen if I were to use the expired cut-off wheel, shown above? Chances are that it will perform as well or nearly as well as a brand new disc. But there’s an increased chance that it will fail, at least compared to a newer and non-expired disc used in the same exact manner.
There are enough risks when using cut-off wheels and grinding wheels. I’m not looking to increase those risks in any way, and so I don’t use expired abrasive discs.
Sure, maybe part of the reason for the expiration is to reduce brands’ liability should a 6 year old disc fail and damage something or worse – someone.
But I’m not going to bet my safety, or anyone else’s, guessing as to whether my expired cut-off wheels are safe to use or not. Why take the chance?
I came across the above disc when digging through some storage boxes, looking for personal tools or old samples to give away or donate. There were only a couple of older cut-off and grinding wheels, maybe ten dollar’s worth.
If you use cut-off and grinding wheels often, you probably rotate your supplies, using the oldest non-expired supplies first. If you’re like me and don’t use angle grinders very often, you might have a small stash of wheels.
As always, you should follow manufactures’ guidelines for the safe use of power tool accessories and consumables. When in doubt, seek professional advice or recommendations.
That all said, what have your cut-off and grinding wheel experiences been like? Have you ever been faced with the choice of what to do with an expired wheel?