Bench grinders in the Metal Shop

I found some grinding wheels for the Bench Grinders in the Metal Shop today that had aluminum ground into them. I ask that you do not use a bench grinder to grind aluminum. This is extremely dangerous to do, we will have signs up soon hopefully.

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And it isn’t just using the wheel to grind aluminum that is dangerous. Using a wheel that is loaded with aluminum is just as dangerous, no matter what you are using it for.

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What CAN we use to work Aluminium ?

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Sanding disks aren’t at risk of cracking in half and flying at high speed when used with aluminum. Some angle grinder wheels are rated for aluminum. But do try to minimize the indoor airborn aluminum.

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Grinding aluminum on a bench grinder can make the wheel explode. I nor anyone at the space that I’m aware of wants that to happen. The consequence is extreme including the possibility of death.

Cutting then sanding is the best way with aluminum.

Here is a MIT link
http://web.mit.edu/course/other/machineshop/Grinder/aluminum.html

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To clarify for anyone else reading this thread, it’s not just aluminum:
*** grinders are not meant for soft metal.*** At All. This includes, surprisingly to many, Titanium.

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Thank you for the addition Jim. Sometimes I forget that what I know & think is common sense isn’t.

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The biggest risk I see potentially is that, unlike the woodshop, there is no “101” for those whom are not familiar with most of the basics. The biggest use case I see someone using aluminum on wheels is the one-off grind that someone less familiar with the metal shop does; they walk in, see a wheel that feels abrasive, and just go for it. I’ve only been with DMS about 1-2 months, so I can’t say if this potential problem happens that often in practice for myself.

There are a lot of “common sense” metal items that are really only common sense if you’ve worked with them already. For example, most probably don’t know that Brass and other Zinc alloys cause Metal Fume Fever when the release while heated and inhaled.

For checking of ferrous metals I’ve honestly been debating the Dangerous Things magentic sensing implant so I can put my hand to it and find out as often I have a metal I don’t know enough about and need to make determinations. I haven’t seen a test magnet in the shop; I’ve seen some that keep one on a peg for a quick spot check. In a shared space where you have users that don’t as many other checks for metal types (hardness tests, identifying by crystalline, spark tests, etc) it may give a false sense of security (for example, alloy that has iron but also Zinc in it like Galvanized materials).

I’m thinking basic spot check; ensure that someone knows not to use Zinc, soft metals on grinders, checking a wheel before use. Kinda like the KMG portion of other classes, but even quicker. Something that simple could also be done by a lot more people and hopefully get others that don’t work with metal as often basic info on the wheels.

I’m not filled in on the full history of what’s gone on in that metal shop, but quick observations from a relatively new member.

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These are signs being purchased
image

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we should probably put this demonstration on as part of a Metal Shop 101 class, too, to help cement the OTHER downsides of aluminum powder in the metal shop with iron powder…

http://www.davidavery.co.uk/thermite/

The new signs have been added. You can not plead ignorance if someone does it. Added the additional signs as well.



I also fixed the cylinder rack last week.


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I found again yesterday that someone had ground aluminum on the Delta Bench grinder. If you see someone doing this, tell them not to. There are still signs posted not to do it. I do not want to see someone get hurt because of it.

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As a very occasional user of the metal shop, are there obvious signs to look for that someone is indeed grinding aluminum. Sparks a weird color, easily differentiated by color and sheen of the stock being ground etc? Can you explain like I’m five, more or less.

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Look for this:
image

There are signs in front grinder that state what can and can not be ground but clearly they can’t see this signs like this out there:
image

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You won’t see any sparks. Or shouldn’t.

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Friday the 12th and Saturday night to Sunday morning mid afternoon some folks we’re working on aluminum in the shop. That should give you enough timeline to search the cams. I did not see grinding or I would have stopped them. They did have a handheld angle grinder with a cutting disk at one point but I was tired and did not remember if cutting was allowed. The primary person was working on the table with the metal sheer by the door.

Funny, but not the signs I was questioning. I meant signs as in visual cues coming from the sparks from the grinder or how aluminum stock differs in look from steel or iron. I’m hardly in the shop and I know not to grind aluminum and there are signs saying such but im not sure how to tell if I need to stop someone.

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As Tim has said, non-ferrous metals like Alum, Copper, Brass, Bronze don’t give off sparks.

Besides ruining the wheel, there is a real danger grinding these metals as they “load up” the grinding wheel and can cause the wheel to fracture and disintegrate throwing pieces around.

Don’t have any specific advice, if you do a LOT of grinding you might notice the difference in sound. But not likely if other noise in there.

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Ok that at least gives me a reason to say “hey that’s not shooting sparks, what are you grinding” , thanks both of y’all. O and I’m stealing that cane picture lol

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Not necessarily what you asked, but here’s what a wheel that’s been loaded up with aluminum looks like

You can see the schmears of aluminum stuck in the grit…

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