# Angle Grinder Direction of Rotation



## wcndave (2 May 2022)

When cutting steel bar for example, I have always had the disc rotating away from me and down, with the sparks going behind me.
I think this is how I always see others doing it too.

I recently found my 9" white label Axminster getting a bit heavy and my 115 Axminster a bit noisy and vibrating a lot, and so went for a Makita 125mm cordless brushless (what a difference!)

But in the manual it shows that the disc should be rotating the other way, and you cut from the back.
To my mind, this means any binding will throw the tool toward you, instead of away from you.

As someone who's not an expert on grinders, can someone out there who is clarify if this seems correct, or just a Makita specific thing, or in fact an error....


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## Sandyn (2 May 2022)

Normally, I use my angle grinder the same way as you, so the angle grinder is rotated 180 degrees compared to the 'correct' picture above. I find that gives me the best control.


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## Sideways (3 May 2022)

Likewise. I want the wheel trying to climb up the workpiece so that 'i'm pulling back on the tool not pushing it into the work. The diagram pictured is wrong to my mind and reduces control. If the wheel starts to bite, the tool will be pushed back towards you, the wheel will try to run down the front face and head for your leg !
Of course you have to pay attention to where the sparks are thrown and adjust the guard for the cut you're making. That's why guards with a tool less adjustment are so good.


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## imageel (3 May 2022)

I think whichever method you use depends on how comfortable you are and sometimes the size/material being cut.
To my mind pic#2 is safer, if the disc binds the force will be downward and worst case you lose grip on the grinder the safety switch will prevent serious carnage.
Also if the to-be-cut-off piece is longish then as you proceed with the cut it is more likely that the end will droop, opening up the cut face and hence minimising likelihood of pinching.

However I think those pictures are misleading in that I'd expect most debris and sparks in pic #2 to be ejected forward and downward and not all the way around the guard and out the back!
Obviously a lot will depend on how close to the guard you work, however for best visibility one would usually start a cut somewhere in the 70-80 degree arc relative to the forward guard edge, and closer to 90 degree or more invites the disc to dig in and not give good control.


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## owen (3 May 2022)

I always use it like the picture, that's the way my dad taught me


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## --Tom-- (3 May 2022)

Worst case is disc shatters - I always try to think in terms of which way fires the fragments away from your limbs


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## wcndave (3 May 2022)

Just a note that in both cases above, the disc is spinning anti-clockwise. The direction of the blade at contact shown by the red arrow.

To my mind *both *are wrong, because the grinder is simply upside-down... Everything I've ever seen in person, or online, shows the cut being done with the disc spinning *down* onto the material.






I had a quick look online, just searching for images of angle grinders cutting, and 90% were with disc on left like the pic just above. However there were enough seemingly reputable pictures going the other way to make me think it's possibly a "real thing"



imageel said:


> To my mind pic#2 is safer


With the disc spinning upwards and any binding throwing the tool at my legs, and knuckles at the bar, I don't think it looks that safe. If you think of the disc spinning the "normal" way, the angle of attack looks much safer - perhaps that's what you were looking at.


imageel said:


> However I think those pictures are misleading in that I'd expect most debris and sparks in pic #2 to be ejected forward and downward and not all the way around the guard and out the back!


Testing like the picture game me about 50/50 front/back


imageel said:


> however for best visibility one would usually start a cut somewhere in the 70-80 degree arc relative to the forward guard edge, and closer to 90 degree or more invites the disc to dig in and not give good control.


Yes, like the real picture above.


owen said:


> I always use it like the picture, that's the way my dad taught me


Which picture? In either case you're saying you were taught to use it with the disc on the right and the front edge of the disc moving in an upwards direction?


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## Dave Moore (4 May 2022)

wcndave said:


> When cutting steel bar for example, I have always had the disc rotating away from me and down, with the sparks going behind me.
> I think this is how I always see others doing it too.
> 
> I recently found my 9" white label Axminster getting a bit heavy and my 115 Axminster a bit noisy and vibrating a lot, and so went for a Makita 125mm cordless brushless (what a difference!)
> ...


Hi,
Looking at these pics they are both wrong. Been in the engineering construction for over 50 yrs and only ever seen a crack handed person use it this way. Even I don’t use it this way and I’m left handed. Turn the grinder over and put the handle in the other side so the wheel cuts down and you are cutting in front of you. I’ve literally cut hundreds of pipes and all my fellow pipe fitters will cut it this way as you have better control and you can cut to a line easier. If you have a good wraparound you can cut a pipe with a square cut more accurately than a bandsaw.
Regards,
Dave


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## Hpps (4 May 2022)

You can get grinders that go the other way. Years ago when I worked for a tool hire company we decided to wind the sales rep up by pretending to have a customer looking for such a grinder. To our suprise they were easy to get hold of, the joke was on us


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## wcndave (4 May 2022)

Dave Moore said:


> Hi,
> Looking at these pics they are both wrong. Been in the engineering construction for over 50 yrs and only ever seen a crack handed person use it this way. Even I don’t use it this way and I’m left handed. Turn the grinder over and put the handle in the other side so the wheel cuts down and you are cutting in front of you. I’ve literally cut hundreds of pipes and all my fellow pipe fitters will cut it this way as you have better control and you can cut to a line easier. If you have a good wraparound you can cut a pipe with a square cut more accurately than a bandsaw.
> Regards,
> Dave


Hello future me.. are you saying both the two images in the Makita picture look wrong to you? I think that's what I was saying, but _why_ did they put this in there? Must be a reason!
Thanks. Dave Moore.


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## wcndave (4 May 2022)

Hpps said:


> You can get grinders that go the other way. Years ago when I worked for a tool hire company we decided to wind the sales rep up by pretending to have a customer looking for such a grinder. To our suprise they were easy to get hold of, the joke was on us


If you turn them over, they all go the other way... which was kind of my point, why is this grinder being held this way up in the pictures to start with....


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## Phill05 (4 May 2022)

If the locking nut is Right hand thread the disk should be on the Left or you risk the disk coming loose and cut down the front of the materiel forcing sparks to go down not at you.


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## HamsterJam (4 May 2022)

I always have the disc on the right so my left arm holding the auxiliary handle is away from the spinny part. 
I also stand slightly left so if a disc did shatter, the bits will be ejected away from me.


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## ChaiLatte (4 May 2022)

Phill05 said:


> If the locking nut is Right hand thread the disk should be on the Left



What about using the disk horizontal, with the nut downwards? And horizontal with it upwards? What hand should it be in those cases? And does it vary in the southern hemisphere?

The only thing that determines the hand of the thread is the direction of rotation.


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## Phill05 (4 May 2022)

Think of using a lathe if you wind the chuck on clockwise then turn on the power the chuck rotates Towards you and lock it'self on the shaft, but if you put the lathe in reverse going Away from you, you risk the chuck flying off and giving you a good slap in the face if your not a lucky person.


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## Doug71 (4 May 2022)

If you turn your grinder upside down the direction of rotation changes relative to the material you are cutting but it doesn't change relative to the tool so the nut isn't going to be coming loose.


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## wcndave (4 May 2022)

Also... ahem... it's x-lock


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## Dave Moore (4 May 2022)

wcndave said:


> Hello future me.. are you saying both the two images in the Makita picture look wrong to you? I think that's what I was saying, but _why_ did they put this in there? Must be a reason!
> Thanks. Dave Moore.


Yes both of the pictures are incorrect. If you start cutting halfway down and working up(obviously with the grinder reorientation, not by their drawings) you will control the grinder better and it won’t run away from you and the sparks will go down to the ground.
Regards,
Dave


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## Marcusthehat (4 May 2022)

45 years of injury free use of a 4.5"/125mm angle grinder, I always have the top of the blade rotating away from me with the sparks generally attempting to set my groin on fire. What other way would one use a small grinder/cutting disc.


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## MikeJhn (5 May 2022)

I learnt the hard way, cutting a screed with a 225mm diamond blade, slight twist and lots of kick, seventeen stitches later, luckily the blade was hot so it part cauterised the wound, not much blood, forgot to mention I was kneeling down at the time so it was my upper leg that has the nice 150mm scar, "familiarity breeds contempt" comes to mind.


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## bansobaby (5 May 2022)

In the original post the grinder is shown in the same position in both images but rotating in different directions. They can't both be correct unless the grinder has a reversing switch, which would be unusual to say the least.
Which way would you prefer to use a chainsaw, cutting down so that the saw tries to pull away from you, or cutting up so its trying to get at you?
Whoever wrote the manual should be doing something different for a living........


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## imageel (5 May 2022)

bansobaby said:


> In the original post the grinder is shown in the same position in both images but rotating in different directions. They can't both be correct unless the grinder has a reversing switch, which would be unusual to say the least.
> Which way would you prefer to use a chainsaw, cutting down so that the saw tries to pull away from you, or cutting up so its trying to get at you?
> Whoever wrote the manual should be doing something different for a living........


I think you've hit the nail on the head ! - I couldn't get my head around why in the 2nd pic the sparks are shown going toward the operator and not away...


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## Doug71 (5 May 2022)

I think it shows them both spinning the same way, in the second picture the sparks go up in to the guard and come out of the bottom


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## guineafowl21 (5 May 2022)

Doug71 said:


> I think it shows them both spinning the same way, in the second picture the sparks go up in to the guard and come out of the bottom


Yes, they both look anticlockwise to me. Every grinder I’ve ever used or seen has spun this way, but has been used with the disc on the left, not the right.

I must say, if I saw someone using a grinder like in the picture, I’d tell them they were using it backwards. The first chainsaws were apparently made like this, (because you push a handsaw), but they were soon altered to the normal direction because of terrible leg injuries from kickback.

Edit: I’d also note that Stihl-type petrol cutoff saws, which you can’t flip over and move the handle, are all designed to run the opposite way to the picture.


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## bansobaby (5 May 2022)

Doug71 said:


> I think it shows them both spinning the same way, in the second picture the sparks go up in to the guard and come out of the bottom


Yes, having looked again I agree-they are both spinning the same way. 
Doesn't alter the fact that the author of the manual should be encouraged to find a different occupation.


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## wcndave (5 May 2022)

You can find photos of people who cut like this.
In any case, the general consensus seems to be that Makita got it wrong in their manual.... thanks!


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## Jonm (6 May 2022)

Sideways said:


> That's why guards with a tool less adjustment are so good.


I agree but when purchasing it is a good adea to check its effect on depth of cut. My son has a 125mm Dewalt 18V, the adjustment clip substantially reduces the depth of cut.

I recently purchased a new mains, 125mm angle grinder. It is an occasional use tool for me so having to use a screwdriver to adjust the blade is not an issue and I do want to maximise the cutting depth. Ended up with a Dewalt based on price and perceived quality. It has a screwed adjuster.

If I was using one regularly and needing to adjust the guard often then I would look for a tool less adjuster which did not reduce the depth of cut.


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## Limey Lurker (6 May 2022)

The pictures were accidentally reversed by the non-grinder-using Art Department drone who did the layout for the hand-book.


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## guineafowl21 (6 May 2022)

Limey Lurker said:


> The pictures were accidentally reversed by the non-grinder-using Art Department drone who did the layout for the hand-book.


Practical types being usurped by arty-farties, yes, could be.

There’s an advert going round, where an emergency plumber saves the day by throwing a tool at a valve to turn off the sprinkler system. But it’s a lever ball valve and it gets turned in the ‘on’ direction.


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## HamsterJam (6 May 2022)

guineafowl21 said:


> Practical types being usurped by arty-farties, yes, could be.
> 
> There’s an advert going round, where an emergency plumber saves the day by throwing a tool at a valve to turn off the sprinkler system. But it’s a lever ball valve and it gets turned in the ‘on’ direction.



Cos I’ve nothing better to do……


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## guineafowl21 (6 May 2022)

HamsterJam said:


> Cos I’ve nothing better to do……
> View attachment 135209


Now the disc is spinning the wrong way!


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## HamsterJam (6 May 2022)

guineafowl21 said:


> Now the disc is spinning the wrong way!



Exactly


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## wcndave (6 May 2022)

guineafowl21 said:


> Now the disc is spinning the wrong way!



Yes, the pictures cannot have been reversed (accidentally or otherwise), nor can be reversed back... because then the discs are spinning clockwise, and that isn't happening.... (that's based on the spark patterns).

So, the discs are always going anti-clockwise, and cannot go clockwise as that would loosen the nut....

Hence, despite all the good natured banter and fun, it seems that some people use the tool so the sparks go away from you, including Makita, however they appear in quite the minority. And there's no reason this AG is different than others and I should follow their picture, rather, I will continue to cut how I always have!

Thanks for all the input - appreciate it!


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## philip sewell (7 May 2022)

At 5.45am on Saturday morning this is making my head hurt. I don't understand it but haven't got the will to try to!


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## Dave Moore (7 May 2022)

wcndave said:


> You can find photos of people who cut like this.
> In any case, the general consensus seems to be that Makita got it wrong in their manual.... thanks!
> 
> View attachment 135123
> ...


Still all incorrect as you don’t have good control.


Jonm said:


> I agree but when purchasing it is a good adea to check its effect on depth of cut. My son has a 125mm Dewalt 18V, the adjustment clip substantially reduces the depth of cut.
> 
> I recently purchased a new mains, 125mm angle grinder. It is an occasional use tool for me so having to use a screwdriver to adjust the blade is not an issue and I do want to maximise the cutting depth. Ended up with a Dewalt based on price and perceived quality. It has a screwed adjuster.
> 
> If I was using one regularly and needing to adjust the guard often then I would look for a tool less adjuster which did not reduce the depth of cut.


 Hi,
The guards that use a screw to hold the guards always come loose . The type of guards I have found are best for adjustment are the type wher you press a spring clip as they don’t require any tools and rotate easily. If you are using cutting discs the discs always tighten up so you cannot get them undone. On a large grinder the best way is to use a spring loaded fastener which allow you to remove the disc with no tools in seconds. On a small grinderette you can get the Milwaukee type which you can twist by hand, if these get too tight you can simply put a screwdriver in the fastener to release.
Regards,
Dave


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## TFrench (7 May 2022)

Dave Moore said:


> Still all incorrect as you don’t have good control.
> 
> Hi,
> The guards that use a screw to hold the guards always come loose . The type of guards I have found are best for adjustment are the type wher you press a spring clip as they don’t require any tools and rotate easily. If you are using cutting discs the discs always tighten up so you cannot get them undone. On a large grinder the best way is to use a spring loaded fastener which allow you to remove the disc with no tools in seconds. On a small grinderette you can get the Milwaukee type which you can twist by hand, if these get too tight you can simply put a screwdriver in the fastener to release.
> ...


I'll second that on the quick release nuts. Someone on here recommended them a few years ago and I've got one on all the grinders I own now!


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## clogs (7 May 2022)

the right hand drawing shows the cutting in the dead zone......
Never cut at the front of the wheel.....
Ive been using cutter grinders for as long as I can remember, even the huge 12"disc's....
and always with the sparks comming out behind me....
cutting the other way u have no real control.....
after long hours working u can rest ur arm on ur leg to help with the weight of the grinder....
next to a hammer my 9" grinder is my most used tool....I buy disc's by the 50.....


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## Dave Moore (7 May 2022)

TFrench said:


> I'll second that on the quick release nuts. Someone on here recommended them a few years ago and I've got one on all the grinders I own now!


And always use a full face visor. If it kicks back on a big grinder you will take your teeth out if you are only wearing goggles and don’t forget the ear protection.


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## joethedrummer (7 May 2022)

philip sewell said:


> At 5.45am on Saturday morning this is making my head hurt. I don't understand it but haven't got the will to try to!


,,I couldn"t wait any longer to find the correct way so just went and cut it with a bloody hacksaw,,


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## TFrench (7 May 2022)

Dave Moore said:


> And always use a full face visor. If it kicks back on a big grinder you will take your teeth out if you are only wearing goggles and don’t forget the ear protection.


Always! Grinder safety is beaten into us on most sites we go on and its one thing I'm more than happy to go along with. The noise really grates on me as well so I always wear plugs when I'm using one. Watched a guy the other day with a stihl saw cutting a roadway using the safety squint method. Just makes you wince.


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