Given my track record with angle grinders, I've been thinking about the safety aspect.
My 9" grinder has a three position 'd' handle & a three position side handle so when cutting vertically you can use it with the disc spinning upwards or downwards. When its spinning 'up' all the muck is thrown towards the operator (me), when spinning 'down' the muck is thrown down at the floor.
From the potential kickback situation, which is safer? If the disc catches whilst spinning 'up' the machine would react by kicking down & away from me.
It seems better to put up with the muck & bullets because the kickback threat is less.
Also, I assume a segmented diamond disc is more likely to kickback than a normal abrasive disc?
================================== The rule I learned is that you stand outside (i.e.to one side)the working line of whatever power tool you're using. If you follow this basic rule the danger from kickback is less dangerous than the danger from flying debris from saw, grinder etc. Having dust and debris flying away from oneself is generally safer than having it flying straight at you like dirt from a terrier's legs.
ROSPA might have some guidelines on the subject, but I think this is a topic where that wiki idea might be useful in gathering 'best practice'.
I always look forward to any post from you with Angle Grinder in the title! Must be a form of morbid curiosity. ;-)
Generally you want to be cutting such that any snag will tend to pull the machine away from you, rather than lob either directly it at you, or kick it in an arc that will eventually intersect with you. It also helps if gravity is working in your favour. Say you were slotting a vertical chase in a wall, then having the grinder no lower than head height would ensure any kick will tend to pull the machine up and out a little, but over your head. This would suggest that you bend your legs / kneel as you progress the cut down. You also want to be cutting in a direction such that the rotation of the disc is pulling the machine into the work and not pushing it away in the same way as a circular saw does.
Having said that, I can't say I have ever had much of a problem with an angle grinder kicking in the first place.
You don't really want the ejected stream pointing straight at you either, especially when cutting metal since it will be hot enough to set you alight!
Other way around I find. Diamond discs offer less cut resistance and remove less material in the first place.
Don't know. Search for "Angle Grinder safety" perhaps?
My thoughts are that if you if you need to ask advice on the use of this type of machine then you should NOT even be THINKING of using it. There are day/evening classes on the safe use of these and similar types of cutters.
Why is it, that there is always some one who comes up with the "if you ned to ask you shouldn't do it" argument. If we all thought that way we would never progress or learn would we?
So, Chas. If you ever want advice on high pressure cleaners, carpet cleaning, or vacuums I will reply (based on 30 years experience) that "if you have to ask you should not even be thinking of it".
I am *really* glad this question has been asked as I thought I was the only noob who did not understand what the safety warnings mean in practice.
What you say is what I have read elsewhere. But I have struggled the few times I have taken my new toys for a spin to see how I can both stand to one side and follow the marked line. That has not mattered much so far as I've only been hacking off spurious bits of garden wall. But it will matter next week when I am due tackle a couple of small (600mm) cuts across a bit of concrete driveway. So if anyone can draw me a picture (if only in words) I'd welcome it.
I did Google around but what I found was not clear. Some of it was some scary. In particular there were many stories of discs disintegrating at speed (so akin to an explosion ) but nothign very clear about how to avoid that happening other than a recommendation to run new discs in a protected area before using them. I am not sure how to do that without special equipment. Is it general practice to do it please? Apart from that is it mainly a matter of buying decent discs and not putting excessive pressure on them?
Oh, and I did also look to see if there were day or evening classes which would cover their use. There are none where I live (or at least none open to a 50-something man who is not in drug rehab/serving out community service/in receipt of JSA...........)
To an extent you need to stand a little to the side to avoid the grinder blocking your line of site of the line anyway. Assuming you are right handed, If you hold the grinder with you left hand on the side handle and have that inline with the middle of your face, and the right on the base handle, then watch the line from the left side of the disc, you will naturally be out of the line of kickback. Make sure the guard on the grinder is positioned so that should it come flying toward you, it is the back of the grinder or the guard that would hit you and not exposed spinning disc.
This applied to abrasive discs, not diamond ones. As long as you use proper grinder discs (the correct abrasive discs are re-enforced with a mesh of strong fibres), and you store them in a dry place, you should be fine. The danger comes if you try using a damp disc or one not designed for an angle grinder. (the small ones spin very fast - 11K RPM)
Just sinning a disc up and running it for 15 secs or so while holding the grinder away from your body with as little of you in the same plane as the disc as possible will achieve this. Obviously make sure the plane of the disc is not pointing at anyone else either.
With masonry, use diamond discs. The only time the abrasive ones are handy is when cutting very soft and abrasive materials, like some limestones or asphalt. Even then you can get appropriate diamond discs for these.
Make sure you have good face and hearing protection. If using goggles, they need to be the indirect vented type and not those with a mesh style direct vent (these will let red hot sparks enter the goggles when grinding metal). A full face visor is preferable in many cases since sparks or stone fragments just hitting your face will hurt. For masonry work, respirtory protection is vital.
If using things like wire brushes then add a leather apron or many layers of heavy fabric to the protective gear - much nicer than pulling wire fragments out of the gonads.
================================== I have occasionally seen people standing astride slabs and timber on the ground whilst using circular saws and angle grinders. This seems to me to be a dangerous method as any kickback is directly in line with the body.
The advice to stand to one side is actually the most natural method if you consider the way you use an electric planer or saw to smooth / cut a long piece of wood on a bench. As far as standing to one side when using an angle grinder is concerned the technique is to hold the angle grinder away from your body but not so far that you can't see the cutting line and judge the correct cutting angle which is normally about 90 degrees to the surface you're cutting. With a bit of care and practice you don't need a direct line of sight to cut a reasonably accurate line.
I'm not too sure about disks 'exploding'. My experience is that disks can break up but the bits tend to fly in line with the normal direction of rotation so this is an additional reason to keep your head out of the line of rotation.
Thank you both. Very helpful (and kind when I had forgotten to look in
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the FAQ, I wonder if someone who has more experience might consider adding that "exclusion zones" should be set up so other people can't be hit by sparks etc or the grinder flails around. Obvious, I know, but it's a point which was emphasised in some of the guidance I did find.
"You also want to be cutting in a direction such that the rotation of the disc is pulling the machine into the work and not pushing it away in the same way as a circular saw does."
... a recipe for kickback. The rest is great advice though.
Given my track record with them, and the record of people I share workshop space with, the biggest improvement to safety is in having a way to switch it off reliably. Especially if you're using an ArborCut disk, you'll find that crud blocks the switches of all angle grinders, from the cheapies to the good ones, such that they won't then turn off when you want them to. Make sure there's an alternative one-handed power switch nearby.
Also (Richard, I mean you!) don't leave plugged in and "live" grinders lying on cluttered benches.
As to kickback, them IMHE this is caused by twisting the disk in the slot and binding on the sides. Abrasive disks are worse than diamond, even segmented.
That would suggest the "normal" direction of cut would be to push the machine away from you cutting with the far edge of the disc.
The only time I cut in this direction is on the first pass on masonry so that you can see your cut line and not cover it in dust. Once you are deep in a cut the natural and safer (IME) is to pull the machine rather than push it.
--------------------------------------------------------- Because angle grinders are designed for grinding and not for cutting, the use of cutting discs with angle grinders exposes operators to even greater risks. WorkSafe Western Australia says: Where a safer alternative cutting tool is available or can be obtained . . . AN ANGLE GRINDER SHOULD NOT BE USED AS A CUTTING TOOL.
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