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Angle grinders - Dangerous or not

Not according to Doug

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Ian Johnson 117/07/2019 22:54:35
174 forum posts
50 photos

Angle grinders are dangerous and should be used with caution.

In my teens I was recovering from a bad motorbike crash with two broken wrists and other injuries, part of the physio was to immerse my hands and wrists into a bath of hot liquid wax, which was supposed to increase circulation. Next to me was another bloke doing the same thing but with one hand.

He had cut his hand off with an unguarded 9" angle grinder, luckily his hand was sewn back on! If you can imagine holding the grinder with both hands, the left hand is gripping the sticky out handle, when the grinder gripped and spun around it cut his hand off! He was using it above head height too! Could have been a lot worse.

And I have been following the build of SV Seeker and there is no way I would go to sailing in that thing!

Ian

Windy18/07/2019 01:50:38
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747 forum posts
221 photos

When I started work many years ago in car body repairs we were using large electric disc sanders similar to large angle grinders.

Tom got the sanding disc on the wrong edge and promptly it jumped out of his hands and cut his wrist the artery was visible.

It was dangerous on thin metal if you didn't approach the job in the right direction. Thank God for all those air sanders a lot safer.

Robert Atkinson 218/07/2019 07:29:18
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400 forum posts
21 photos

It's the video that's dangerous.

It implies that you can abuse an angle grinder and use it without a guard and nothing bad will happen.
Just about any tool with an exposed cutting edge is potentially lethal, if it's powered then it's worse. They all need to be treated with respect. I have a Dewalt battery powered vibrating multitool which is great for softer materials and you can touch the running blade without injury but even dropping it switched off it could cut an artery if it hit the wrong spot.

Another interesting point about this sort of video is that the makers are potentially opening themselves up to lawsuits, especially in the USA. You are responsible for advice you give people.

Robert G8RPI.

Edited By Robert Atkinson 2 on 18/07/2019 07:31:41

Phil H118/07/2019 10:15:35
197 forum posts
33 photos

Well something isn't quite right with the angle grinder demonstration at the start of this thread.

About 6 years ago, a chap was unfortunately killed on a construction site associated with the company I was working for. I don't know the exact accident sequence but it was an angle grinder and a cutting disc. He was unfortunately killed when the cutting disc disintegrated. They are dangerous.

Phil H

Stueeee18/07/2019 11:16:50
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31 forum posts

Also the tool needs to be fit for purpose to be safe. This angle grinder bought new from eBay had a gearbox casing made of pure Chinesium. The first angle grinder arrived with a faulty switch, so I returned it. This is what happened to the replacement after 30 minutes use. This time I decided to cut out the middle man and threw it in the bin before buying a decent branded grinder.

Robert Atkinson 218/07/2019 12:40:17
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400 forum posts
21 photos

I would not recommend buying any mains powered item from any far eastern seller on ebay or the like even if they appear to be UK based. For anything critical I will only use reputable established suppliers and brands.
I have recently seen a spate of dodgy kit:

A laptop style power supply supplied with an LED face mask beauty treatment system that I refused to pat test at all. I cut the leads off and broke it open and even the completely not technical owner could see the internal construction was terrible.

A 5V DC plugtop style power supply that had a loose circuit board inside, un insulated mains connections and less than 0.5mm creapage / clearance between the mains live connection and the output 0V

A PC style power lead with a fuse-less imitation of a 13A plug and conductors of 4 thin strands of something copper coloured but very springy. probably steel but I didn't even check before cutting it into short lengths.

All lethal and / or capable of starting a fire.

Robert G8RPI.

ChrisB18/07/2019 13:36:31
429 forum posts
171 photos

To be fair with the guy on the video, he is not suggesting you do what he did, my take is his advice is to use common sense. If you lack common sense in handling tools, then the workshop is no place for you as no matter how many guards your tools have and no matter the ppe used, you will get hurt!

Robin18/07/2019 14:30:53
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318 forum posts

My memory is getting old and tired. I remember cutting my finger with an angle grinder, I remember how much it hurt, but blowed if i can remember how I did it. Makes it slightly tricky to avoid doing it again? cool

larry phelan 118/07/2019 15:44:22
527 forum posts
11 photos

All tools are dangerous in the wrong hands, angle grinders no more so than any other.

It all comes back to the user.

Jim Butler 118/07/2019 16:12:32
6 forum posts

I had a close encounter with an angle grinder in the past week.

I needed to change from a cutting disc to a wire brush, so I turned of the mains power at the wall and took off the cutting disc an attached the brush.

So far so good, but when I reached out to turn the power on at the wall, the grinder started up.

As I was holding the grinder quite lightly in my left hand, due to the torque reaction it jumped out of my hand and fell at my feet and the wire brush started grabbing at the legs of my overalls.

Luckily it did not grab tightly, and as my right hand was next to the mains switch I was able to kill the power very quickly.

So how did this come about?

As I was handling the grinder in the course of changing the disc/brush I had operated the switch on the grinder to the on position. So as soon as mains power was applied, it burst into life.

The switch on the grinder ((Bosch) is either OFF or locked in the ON position.

Lessons learned:

Always switch off power at the wall when changing discs.

Before switching on power at the wall, check the switch on the tool.

JimB

Daniel18/07/2019 16:52:35
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254 forum posts
39 photos

Jim,

Although it hasn't happened yet, I've long since noticed the potential for that to happen.

Perhaps an NVR (No Volt Release) switch would be an appropriate development by the manufacturers.

ATB (All The Best),

Daniel

ega18/07/2019 17:16:42
1333 forum posts
109 photos
Posted by Daniel on 18/07/2019 16:52:35:

Jim,

Although it hasn't happened yet, I've long since noticed the potential for that to happen.

Perhaps an NVR (No Volt Release) switch would be an appropriate development by the manufacturers.

ATB (All The Best),

Daniel

Plus 1 for the NVR.

The more recent machines have a soft start feature which is a significant advantage on a big angle grinder. A brake on switch off would also be a good idea.

My grinders are fitted with a short lead with connector for fitting to an extension lead which makes it possible to disconnect the grinder when changing discs etc without necessarily having to get to the socket outlet.

Neil Wyatt18/07/2019 20:55:03
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Moderator
16740 forum posts
689 photos
76 articles
Posted by Stueeee on 18/07/2019 11:16:50:

Also the tool needs to be fit for purpose to be safe. This angle grinder bought new from eBay had a gearbox casing made of pure Chinesium. The first angle grinder arrived with a faulty switch, so I returned it. This is what happened to the replacement after 30 minutes use. This time I decided to cut out the middle man and threw it in the bin before buying a decent branded grinder.

It will be impossible to know for sure, but it may well be that a sub-standard batch found its way out the back door of the factory and into a container bound for the UK.

In such a case they might look identical to name brand ones, and just differ by having the casting made from the wrong alloy or some such issue...

Neil

Ed Duffner19/07/2019 00:21:45
733 forum posts
61 photos

We had a customer come into the shop a couple of months back, asking for a 9-inch TCT wood cutting blade and non-standard step-washer / bush.

Not immediately obvious what he was looking to do, but after a chat he basically wanted to fit the blade onto his angle grinder to cut out a tree stump. He was politely sent on his way after being advised of the potential danger.

Ed.

Kiwi Bloke19/07/2019 06:05:48
264 forum posts
1 photos

Nasty, dangerous and scary machines, but I'll continue to use mine and hope to get away with it. The alternative doesn't bear thinking about.

In Oz & NZ, Jaycar sell a soft starter kit for power tools. I've just bought a second one. I think they are running low on stock. The design was published in Silicon Chip magazine, July 2012. It reduces the start-up kick quite well. The design is, I think, unnecessarily complex. In essence, a NTC thermistor, with a cold resistance of about 20 Ohm, is in series with the load, until it's shorted out after about 0.5 second. Not only is the kick reduced, for the benefit of the operator, but the inrush current is severely limited, which may be helpful in some electrical installations.

john carruthers19/07/2019 08:45:58
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597 forum posts
175 photos

What could possibly go wrong? wink

carving disc link

MichaelR19/07/2019 08:55:44
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346 forum posts
61 photos
Posted by john carruthers on 19/07/2019 08:45:58:

What could possibly go wrong? wink

carving disc link

There are some lethal looking attachments on that link, sends a shiver up the spine.

Mike.

ega19/07/2019 11:05:18
1333 forum posts
109 photos
Posted by Kiwi Bloke on 19/07/2019 06:05:48:

Nasty, dangerous and scary machines, but I'll continue to use mine and hope to get away with it. The alternative doesn't bear thinking about.

In Oz & NZ, Jaycar sell a soft starter kit for power tools. I've just bought a second one. I think they are running low on stock. The design was published in Silicon Chip magazine, July 2012. It reduces the start-up kick quite well. The design is, I think, unnecessarily complex. In essence, a NTC thermistor, with a cold resistance of about 20 Ohm, is in series with the load, until it's shorted out after about 0.5 second. Not only is the kick reduced, for the benefit of the operator, but the inrush current is severely limited, which may be helpful in some electrical installations.

Does anyone know of a UK equivalent, preferably one that could be incorporated in the lead?

Juddy19/07/2019 11:21:44
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63 forum posts
Posted by MichaelR on 19/07/2019 08:55:44:
Posted by john carruthers on 19/07/2019 08:45:58:

What could possibly go wrong? wink

carving disc link

There are some lethal looking attachments on that link, sends a shiver up the spine.

Mike.

Yes like this one, **LINK**

makes an angle grinder look like a childs toy

Ian S C19/07/2019 14:24:01
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7447 forum posts
230 photos

At least those things in the last link by Juddy are for a Weed Whacker, so limited to about 3000 rpm, not the high revs of an angle grinder. Still really too dangerous, one of those chains only needs to hit a rock to destroy it and bits of chainsaw chain flying every where.

Ian S C

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