Yes i am stupid for using a cheapo grinder!

[zardoz]

And today i got my come-uppance, even though i am aware i got off very lightly. The grinder in question is one of those cheap 'Blackspur' models. Nothing wrong with cheap though. Unless it equates with dangerous! This particular model is either switched off or switch 'locked' on There is no way you can just grind only as long as the switch is pressed. In other words it locks itself on until you unlock it for off.

So today i was bored and doing one of those jobs that dont really need doing, and have been put off for such times as this. ie: I was going to try out the twist knot wheel i had bought for the grinder, by giving one of my 'right angles' a once over, as it had got a tad rusty in the shed.
So after approx 20 seconds grinding the grinder is spun away off the edge of the right angle, and onto the back of my glove. The end result being this:

I realized how lucky i was that i had been wearing gloves, even if it was only the Thinsulate kind (with lining) Though obviously should have been wearing sturdier hand protection. The grinder seemed to leap off the end of the angle onto my glove. Where i stared in amazement for approx 3 milliseconds before realizing it was still trying to move round, and i tore it away and hurled it to the ground, where it immediately started up again!

So after realizing my close escape, i straight away smashed the grinder to bits, to stop me being tempted
to use it 'just once more'

One thing puzzled me though after seeing it smashed up. What on earth are the small drill type indentations on the outsides of the armature ? (or whatever it is?)

 

[malcolm]

Ooch! Not just the cheapo ones that do that - pricer ones have the same trouble. Fairly sure my blue bosch has a latching switch as the only alternative. Don't know why they don't take the same approach as electric drills.

Was grinding on the underneath of an immaculate Renault tail gate (rare part) and had the underside protected from the floor with a blanket. You can guess the rest and how the tailgate got all dented. Had to unplug it from the extension to make it stop.

Those drill holes - are they for balancing? If so they'd be on one side only.

 

[Welderpaul]

I've done it. It grabbed the front of my overalls and kept twisting till it stalled. Overalls became very tight in the gusset area if you know what i mean.

 

[nickburt]

Sorry to read about your experience. Hope the hand heals quickly.
I think you were quite lucky though, it could have been a lot worse.

The grinder and maybe it's design needs reporting to trading standards/watchdog etc... etc...

The drill type marks in the armature are probably a balancing exercise by the manufacturer.

 

[bill_gj]

I was once involved with electric motors for fuel injection pumps and yes, the indentations are for balancing purposes. As for the number of drillings, it's very much to do with:
- the quality of the armature,
- the quality of the winding process
- the quality of the balancing process

If you take a Bosch (proper Bosch, made in Germany) motor apart, you'll find just a few drilled indents. Sometimes they're not drillings but crescent-shaped millings.
Take apart a similar pump motor, from India or China, say, and you'll see more cuts to get the balance right.

 

[bill_gj]

By the way Zardz - felicitations on your lucky escape. Merry Christmas. I hope your fingers aren't going to be so swollen that you won't be able to hold a glass. I will have one for you.

 

[dcocks]

Nasty that
but do not all small grinders have that sort of switch my hitachi does.
my 9 inch stops when you take your finger of the trigger
david

 

[nickburt]

Daft as it sounds - I can't remember how the trigger works on any of my small grinders - just shows how much "automated" operation we do !!!

 

[malcolm]

If you take a Bosch (proper Bosch, made in Germany)

Do they still make any tools in Germany? All the stuff I've come across has been made in China (presumably to proper Bosch quality standards if you ignore the last one I had).

 

[Wozzaaah]

I've done it. It grabbed the front of my overalls and kept twisting till it stalled. Overalls became very tight in the gusset area if you know what i mean.

And me! Exactly the same, wire brush snagged on an edge and shot backwards.

 

[snowcat]

The metebo ones are off or on also, Its only the 9" grinders that have the fail safes on them, I also have a bad habbit of removeing the guards, so I can reach round the back of webings on UB's....Which is partly to blame for a few of the scars on me hands.

Yep the cup brushes are the worst for grabing, but cant really blame the grinders as im normaly holding with one hand and feeding meterial to it with the other

 

[JimM]

Nasty that
but do not all small grinders have that sort of switch my hitachi does.
my 9 inch stops when you take your finger of the trigger
david

That's what I thought too.

Obviously in this case it didn't work out too well but I know when I'm grinding my thumb would be dead if I had to keep pressure on the switch all the time.

As you said Zardoz lucky you were wearing some sort of gloves and your mishap will hopefully encourage me to put mine on next time I think I can't be bothered.

 

[zardoz]

The only sort of grinder i am buying in future has a 'drill type' switch that can be set to stop as soon as you release the trigger. Surprised to realize that more expensive models do this too though. As this was the first thing I noticed when I got it home, a few years back, and I just put it down to being a cheap model. I did however see a cheap one last week that had the 3 settings. Only £17 I knew that I should have bought it. If its still there after xmas i'm on it.

Not sure what type of gloves could be considered 'grinder proof' though. As long as they keep the grinder out for a few seconds, for reaction time, that would be enough. Anyone have any ideas?

 

[snowcat]

I buy the green double lined welding gloves by the box wear them for everything......

 

[TAITSIE]

Lucky man Zardoz hope you enjoy eating your xmas dinner with all your fingers intact,have just checked my grinder,a 4 1/2 Metabo,supposed to have an anti grab clutch,also the switch is either on or off no automatic release.

 

[Drains]

Nowt wrong with a latching switch, IMO, not least because it allows you to grind one- handed, in strange positions. Give me latching every time (on grinderettes)

Twist knot wheels are notoriously dodgy and have to be treated with respect. I think most people have had accidents with them. I have also ended up with a big one on me 9 incher (ohh, er, missus), enveloped lovingly in the folds of my overalls, and a nasty set of grazing on my leg!

 

[snowcat]

Nowt wrong with a latching switch, IMO, not least because it allows you to grind one- handed, in strange positions. Give me latching every time (on grinderettes)

Twist knot wheels are notoriously dodgy and have to be treated with respect. I think most people have had accidents with them. I have also ended up with a big one on me 9 incher (ohh, er, missus), enveloped lovingly in the folds of my overalls, and a nasty set of grazing on my leg!

Ohh you as well, My left knee has a scar around 2" long from the bugger on the 9"...but I was wearing shorts at the time another bad habbit

Nope agree with the latching I cant stand baby grinders without it........

Anyway cut's and brusies are just part of the course...

There just mear flesh wounds....

 

[zardoz]

In my ever so umble opinion. Latching switches are great. As long as you have the option to use the drill type pressure release switch as well.

 

[burntmebonce]

i allway wear my welding gloves also great for keeping the sparks out of your sleeves

 

[Welderpaul]

The metebo ones are off or on also, Its only the 9" grinders that have the fail safes on them, I also have a bad habbit of removeing the guards, so I can reach round the back of webings on UB's....Which is partly to blame for a few of the scars on me hands.

Yep the cup brushes are the worst for grabing, but cant really blame the grinders as im normaly holding with one hand and feeding meterial to it with the other

I have been known to take the guard of once or twice for a specific job but its gone back on after. Nowt worse that taking a big lump of skin off with the grinder. i know people that when they buy a grinder, first thing they do is take the guard off. Aint worth it having a disc running at 5000 rpm mm's from yer knuckles.