Cheap Discs and Angle Grinders

[mjac]

Hate to break it to you....

that's a rebranded Hitachi grinder, they merged with Metabo recently. Notice the HPT (made in China)...

It's a standard issue grinder, no better or worse then most Milwaukee's, Dewalts, etc....

But if you are truly in search of a "safer" grinder, Metabo and a few others offer kick-back tech that wouldve prevented your issue (maybe)

Personally I would rather rely on proper technique first, and have the tech and quality as a backup. I would suggest watching a few vids about grinding techniques and safety then explore better gear.
Cheers

That is not a rebranded Hitachi, that is a Metabo built in Metabo’s plant in Chins to Metabo’s specifications as are many Metabo products below a certain price point. I know my Metabos baby.

Thanks
mjac

 

[whateg01]

That is not a rebranded Hitachi, that is a Metabo built in Metabo’s plant in Chins to Metabo’s specifications as are many Metabo products below a certain price point. I know my Metabos baby.

Thanks
mjac

Sure do!

 

[mjac]

Sure do!

Must be a case of mislabeling, there must have been a bucket of those HBT name plates around the Metabo Shanghai plant and a line worker put them on by mistake.

Thanks
mjac

 

[mjac]

I still have tubs of them from when I was running my welding rig. Zip discs, grinding wheels, flap discs and wire wheels. I started buying them in 2005 when I became self employed and I also got quite a few from the tool crib. We also can’t use a grinder on any industrial job site around here without a guard, handle, or trigger lock. We would get run off the job. I even leave my guards on at home just because I have seen enough films of damage shattered discs have made.

Well, I bought some Makita cutting discs that are supposed to be good, tried them today and they are garbage. The Warrior cutting discs were better, smoother and wore better. Got disenchanted with friction discs and ordered a Lennox MetalMax metal body diamond encrusted blade. We will see how that works out…

Edit: Just found out how slow the Lennox MetalMax is, there is no way. Have to figure out which Walter to buy.

Thanks
mjac

 

[finn]

That is not a rebranded Hitachi, that is a Metabo built in Metabo’s plant in Chins to Metabo’s specifications as are many Metabo products below a certain price point. I know my Metabos baby.

Thanks
mjac

Does it really matter? Metabo and Metabo HPT are both owned by Koki Holdings as a result of the merger ten years ago.

A press release from last year states that the Metabo name will transition to Metabo HPT beginning last November and be complete by spring 2026. The Metabo (HPT) German made tools sold in North America will transition from the European CAS batteries to the existing Metabo HPT multivolt battery system currently used here.

Bottom line: Both the old Metabo (Germany) and the old Hitachi (Metabo HPT) had grinders or components made in China. The higher power versions are of the old Metabo line were made in Germany, and that will continue when the Metabo name disappears this spring and the brand is fully integrate into the Metabo HPT nomenclature. They’re the same company.

I just bought another Metabo grinder a few weeks ago, my second. It’s listed as made in Germany and has a 12.0 amp rating. It’s a heavy *******, and I generally prefer the ergonomics of light tools, so I suspect this one will largely be a wall hanger. Maybe good for an ironworker with Popeye arms, but it may be overkill for me. In retrospect, the Metabo I already have is rarely my go to grinder, But then again, this is GJ, where “go big or go home” is the macho man rallying cry.

I think the OP’s grinder is a 6.2 or 6.4 amp, made in China version. Metabo (Germany) established a manufacturing plant in Shanghai China in 2005, a good ten years before the Hitachi merger. I don’t know if the HPT grinders are made in that same plant, or if it strictly provided components to Germany. I think Hitachi moved production from Japan to China in the same time period.

 

[mjac]

Does it really matter? Metabo and Metabo HPT are both owned by Koki Holdings as a result of the merger ten years ago.

A press release from last year states that the Metabo name will transition to Metabo HPT beginning last November and be complete by spring 2026. The Metabo (HPT) German made tools sold in North America will transition from the European CAS batteries to the existing Metabo HPT multivolt battery system currently used here.

Bottom line: Both the old Metabo (Germany) and the old Hitachi (Metabo HPT) had grinders or components made in China. The higher power versions are of the old Metabo line were made in Germany, and that will continue when the Metabo name disappears this spring and the brand is fully integrate into the Metabo HPT nomenclature. They’re the same company.

I just bought another Metabo grinder a few weeks ago, my second. It’s listed as made in Germany and has a 12.0 amp rating. It’s a heavy *******, and I generally prefer the ergonomics of light tools, so I suspect this one will largely be a wall hanger. Maybe good for an ironworker with Popeye arms, but it may be overkill for me. In retrospect, the Metabo I already have is rarely my go to grinder, But then again, this is GJ, where “go big or go home” is the macho man rallying cry.

I think the OP’s grinder is a 6.2 or 6.4 amp, made in China version. Metabo (Germany) established a manufacturing plant in Shanghai China in 2005, a good ten years before the Hitachi merger. I don’t know if the HPT grinders are made in that same plant, or if it strictly provided components to Germany. I think Hitachi moved production from Japan to China in the same time period.

Well, is it an Hitachi tool rebranded with the Metabo name, or is it a Metabo…

Thanks
mjac

 

[finn]

Well, is it an Hitachi tool rebranded with the Metabo name, or is it a Metabo…

Thanks
mjac

Looks likec a carryover Hitachi that adopted or inherited the Metabo HPT name and label after the “merger”, best I can tell.

That doesn’t make it bad, in my eyes.

The German Metabo I just bought was an Amazon warehouse deal, listed as “used”, although there was no sign it ever had a disc installed. The box was beat up, though. It’s quite a bit heavier than the Metabo HPT grinders I see at Lowe’s, although I’ll qualify that by saying it’s been a long time since I looked closely..


The one at my Mi house is similar in weight to this one.

 

[mjac]

Looks line a carryover Hitachi that adopted or inherited the Metabo HPT name and label after the “merger”, best I can tell.

That doesn’t make it bad, in my eyes.

The German Metabo I just bought was an Amazon warehouse deal, listed as “used”, although there was no sign it ever had a disc installed. The box was beat up, though. It’s quite a bit heavier than the Metabo HPT grinders I see at Lowe’s, although I’ll qualify that by saying it’s been a long time since I looked closely..


The one at my Mi house is similar in weight to this one.

Well, I have a glorified Hitachi…

Thanks
mjac

 

[mjac]

Took a shot, found a pack of 22 Walter Zip ** 4 1/2” Ceramic Cut Off Discs for $64 on Ebay. Hope it is a straight up deal, because we all know those discs caused that accident…

Edit: Thanks to the people who recommended Walter.

Thanks
mjac

 

[neophyte]

Does it really matter? Metabo and Metabo HPT are both owned by Koki Holdings as a result of the merger ten years ago.

A press release from last year states that the Metabo name will transition to Metabo HPT beginning last November and be complete by spring 2026. The Metabo (HPT) German made tools sold in North America will transition from the European CAS batteries to the existing Metabo HPT multivolt battery system currently used here.

Bottom line: Both the old Metabo (Germany) and the old Hitachi (Metabo HPT) had grinders or components made in China. The higher power versions are of the old Metabo line were made in Germany, and that will continue when the Metabo name disappears this spring and the brand is fully integrate into the Metabo HPT nomenclature. They’re the same company.

I just bought another Metabo grinder a few weeks ago, my second. It’s listed as made in Germany and has a 12.0 amp rating. It’s a heavy *******, and I generally prefer the ergonomics of light tools, so I suspect this one will largely be a wall hanger. Maybe good for an ironworker with Popeye arms, but it may be overkill for me. In retrospect, the Metabo I already have is rarely my go to grinder, But then again, this is GJ, where “go big or go home” is the macho man rallying cry.

I think the OP’s grinder is a 6.2 or 6.4 amp, made in China version. Metabo (Germany) established a manufacturing plant in Shanghai China in 2005, a good ten years before the Hitachi merger. I don’t know if the HPT grinders are made in that same plant, or if it strictly provided components to Germany. I think Hitachi moved production from Japan to China in the same time period.

Hitachi has been making power tools in China, probably since the 1990s or earlier.
The hitachi hand power tools available on the US market used yo be fairly affordable, and while generally considered a step up in quality From the older dark blue USA made Ryobi power tools, the Hitachi tools in many cases were still sort of considered a “budget” professional brand, but one that sometimes had very hood engineering, and which worked well.
There were exceptions like miter saws, and the pneumatic nailers, which generally had a very hood reputation as being “industrial quality” but that reputation really didn’t cover the entire line.

 

[neophyte]

Well, is it an Hitachi tool rebranded with the Metabo name, or is it a Metabo…

Thanks
mjac

It’s a Hitachi angle grinder rebranded as Metabo.
Metabo has had some cheaper tools that were made in China for I think at least a couple decades, and even before that had cheaper, lower quality products in their German made offerings, and Hitachi did own Metabo gor a bit before the merged Hitachi/Metabo power tool line was sold to KKR, so it would require extensive research to determine current and former component and quality changes.

Basic angle grinders are relatively simple, and even a low cost Hitachi or Metabo, should be fairly similar in general safety, to an older Bosch grinder, or an older Industrial German made Flex Grinder, or an older Milwaukee, or AEG grinder.
It’s usually the more expensive fancier top line tools from any brand that diverge more in features, and safety components.
The major differences might be smoothness, and lifespan between brands.

 

[mattthemuppet]

Wheels that kicked back were brand new Black & Decker discs, not used. All previous cuts and finish cut to finish cut started by the Black &. Decker discs were made with a used Warrior disc. The kickbacks were caused by the two Black & Decker wheels, not technique. Same technique was used several times with the Warrior wheels. Physical Evidence…

Thanks
mjac

You misread. New wheels are more likely to kickback because they’re physically larger (higher surface speed, more leverage) than used wheels. The fact that you got kickback with two new wheels and didn’t with a used wheel supports this.

 

[seber]

No guard. No handle. That is a guaranteed recipe for trouble. Your technique *****.

 

[liliysdad]

No guard. No handle. That is a guaranteed recipe for trouble. Your technique *****.

There isn’t a grinder in my shop with a guard or a handle. I have a quick-attach guard for a couple of my Dewalts that I will throw on there if I need to direct sparks away from something, but that’s in the drawer more often than not.

Guards and handles make it too difficult to get the grinder in places I want to get it. Yeah, I understand the risks, and make efforts to mitigate them to a level acceptable to me.

 

[mjac]

It’s a Hitachi angle grinder rebranded as Metabo.
Metabo has had some cheaper tools that were made in China for I think at least a couple decades, and even before that had cheaper, lower quality products in their German made offerings, and Hitachi did own Metabo gor a bit before the merged Hitachi/Metabo power tool line was sold to KKR, so it would require extensive research to determine current and former component and quality changes.

Basic angle grinders are relatively simple, and even a low cost Hitachi or Metabo, should be fairly similar in general safety, to an older Bosch grinder, or an older Industrial German made Flex Grinder, or an older Milwaukee, or AEG grinder.
It’s usually the more expensive fancier top line tools from any brand that diverge more in features, and safety components.
The major differences might be smoothness, and lifespan between brands.

Another old school company, bought up, moved around and massaged. It never ends…Had no idea.

Thanks
mjac

 

[mjac]

No guard. No handle. That is a guaranteed recipe for trouble. Your technique *****.

No guard, no handle, that is factual for various reasons, technique does not ****. There are different ways to introduce safety, it does not always have to be by the book and sometimes are more effective as long as it is conscientious and thought out. Following the book blindly can be dangerous too.

Thanks
mjac

 

[mjac]

There isn’t a grinder in my shop with a guard or a handle. I have a quick-attach guard for a couple of my Dewalts that I will throw on there if I need to direct sparks away from something, but that’s in the drawer more often than not.

Guards and handles make it too difficult to get the grinder in places I want to get it. Yeah, I understand the risks, and make efforts to mitigate them to a level acceptable to me.

It sounds like you actually use the tool and not theorizing. I want to know how you feel about this. I believe having both hands on a 4 1/2” angle grinder, not one on a handle, when cutting gives you more precise control to prevent side pressure on the cutting disc and to apply the right pressure. I have found guards interrupt the sight line so you can not see what you are doing in the cut which increases the chance of a kickback. That on top of not being able to fit the grinder into certain spaces with a guard and handle. Good goggles, good full face shield, leather apron, enough?

Thanks
mjac

 

[mjac]

You misread. New wheels are more likely to kickback because they’re physically larger (higher surface speed, more leverage) than used wheels. The fact that you got kickback with two new wheels and didn’t with a used wheel supports this.

I went back and reread the post, did you edit that, I do not remember reading it like that, but that could be me. The way it reads now, you can not mistaken the intent.
It had to be the wheels, because if it was not the wheels it would have to be me and we know that is not possible.

Thanks
mjac

 

[mjac]

LINEMASTER sent me this link but the engineer sent me another Email saying he sent the wrong link and I can not figure out how to delete the attachment, so disregard this attachment and I will send another one…

Thanks
mjac

 

[liliysdad]

It sounds like you actually use the tool and not theorizing. I want to know how you feel about this. I believe having both hands on a 4 1/2” angle grinder, not one on a handle, when cutting gives you more precise control to prevent side pressure on the cutting disc and to apply the right pressure. I have found guards interrupt the sight line so you can not see what you are doing in the cut which increases the chance of a kickback. That on top of not being able to fit the grinder into certain spaces with a guard and handle. Good goggles, good full face shield, leather apron, enough?

Thanks
mjac

I think removing the handle and guard goes against every basic textbook safety tenet on earth. I also, simultaneously, believe that removing these items make the grinder more efficient and use for my needs.

I further believe that a face shield, long sleeve shirt, leather apron, gloves and steel toed boots are best practice while grinding….and that those things are pain in the *** and I don’t wear them. Gloves and eye pro are about as good as it gets in my world.

 

[mjac]

I think removing the handle and guard goes against every basic textbook safety tenet on earth. I also, simultaneously, believe that removing these items make the grinder more efficient and use for my needs.

I further believe that a face shield, long sleeve shirt, leather apron, gloves and steel toed boots are best practice while grinding….and that those things are pain in the *** and I don’t wear them. Gloves and eye pro are about as good as it gets in my world.

What is an eye pro?

Thanks
mjac

 

[mjac]

Can’t get link to work…

 

[mjac]

Product | Linemaster Switch Corporation

linemaster.com

This should be the correct link from LINEMASTER for the foot switch the engineer recommended for the angle grinder in the conditions I described to him. (not an industrial setting)

 

[liliysdad]

What is an eye pro?

Thanks
mjac

Eye Protection…sorry.

 

[mjac]

Eye Protection…sorry.

You keep it basic…

Thanks
mjac

 

[Bad Habit]

Just imagine the grief you would have saved yourself (from this thread) if you got a drycut saw...

 

[whateg01]

Just imagine the grief you would have saved yourself (from this thread) if you got a drycut saw...

I can only imagine the thread that follows op trying to freehand a cut with one!

 

[mjac]

Just imagine the grief you would have saved yourself (from this thread) if you got a drycut saw...

Chop Saw?

Thanks
mjac

 

[mjac]

I can only imagine the thread that follows op trying to freehand a cut with one!

I can freehand anything baby, especially with my METABO…

Thanks
mjac

 

[whateg01]

Chop Saw?

Thanks
mjac

Similar in operation but chop saws are generally a fast spinning saw, often abrasive. Cold cut or dry cut uses a carbide tipped blade

 

[Bad Habit]

Chop Saw?

Thanks
mjac

Yep, like an Evolution. If you're cutting metal even just a few times a year, it's well worth it. Cuts clean and smooth as butter

 

[mjac]

Yep, like an Evolution. If you're cutting metal even just a few times a year, it's well worth it. Cuts clean and smooth as butter

You got me thinking, I have a chop saw, for precision wood cuts, I could buy a good Walter blade for it and do all of the open area cuts on it and just use the Metabo in confined spaces and for grinding. A whole lot safer. Might have to secure the workpiece with c clamps, wouldn’t want to be holding a piece of steel with my hands while cutting with a friction blade. I have to cut a 2” x 3” - 1/4” angle to brace a truck door hinge, that would be a whole lot easier. Hate to mess my saw up but might be worth it. Let me see what that Walter blade would cost.

Thanks
mjac

 

[neophyte]

No guard, no handle, that is factual for various reasons, technique does not ****. There are different ways to introduce safety, it does not always have to be by the book and sometimes are more effective as long as it is conscientious and thought out. Following the book blindly can be dangerous too.

Thanks
mjac

You were wearing nylon athletic pants according to one of the early posts in this thread.
While “athletic pants” may in some cases be perfectly safe, generally “nylon ones aren’t, because many types of nylon fabrics are flammable, or meltable, and grinding creates sparks which can cause clothing to catch on fire, or melt, neither of which is pleasant, or safe.
If you want to wear “stretchy” “athletic pants”, while grinding, buy ones that are 100% cotton, or close yo it, and cut iff a piece of fabric from the cuff and do a burn test to make sure the fabric won’t melt of go up in flames.
There are also FR rated cotton sweat pants available that are treated specifically to prevent combustion.
As for removing the guards, (and the side handle), this is not necessarily safe, but the newer skinnier brushless grinders some manufacturers make, including Metabo, have a smaller diameter and would be easier to grip and maintain control of when being used in an awkward place without guards.
These grinders are also available with paddle switches, which would be even safer if you remove the safety guards.

Generally,
No safety system or component makes something inherently safe, or provides 100% safety, or even close.
Most user safety recommendations and usage instructions, also don’t provide 100% safety, but those instructions do help minimize injury or prevent injury in the case that something goes wrong.
Proper attire, and “grooming”, also helps prevent injury. (Ie. Long hair that can get grabbed by a grinder, and loose clothing that can as well).
Properly stored and safely aged grinding and cutting discs can also come into play, and may help prevent issues as well, along with having potential safety features built in, such as discs that get slightly thinner towards the center, to help prevent binding. (I forget who makes/made these discs).

If you follow the regular proper safety procedures, such as an angle grinder with a cutting guard, using the grinder with the discs cutting in the proper direction, preventing pinching of the cut material, having the cutting disc facing away from you while cutting, having a proper grip on the grinder, etc.,
You can use the shittiest discs imaginable, ones that might easily shatter, just with a little side loading, and there is likely a 99.9% chance you will not get injured making a cut, even with those ****** discs.
For all your claims about “knowing what you were doing”, everything you have said about what you were wearing, and how you were using the grinder, seems to indicate you don’t actually understand safe grinder use.
Grinder wheels spin around, so the linear direction one side is going, is going to be opposite to the linear direction of the opposite edge, a grinder guard can mostly prevent this
From being a safety issue, but if you remove the guard, then an errant touch on the wrong edge that is left exposed can cause the grinder to force itself in the opposite direction than what you might be expecting, and this is worse when cutting in an enclosed space, since the grinder can “bounce around”, like a pinball, once control is lost.

If you need better visibility in an enclosed space, maybe buy some mirror acrylic off cuts from a plastic supplier, and makeup mirrors for better view in the enclosed space.
Arbortech also makes a clear polycarbonate guard for use with their carbide tipped carving blade, and the guard is designed to be retrofittable to smaller grinders. The polycarbonate should be capable of protecting the user from a shattered wheel, and is designed do that cut depth can be limited.
It’s also fairly cheap as far as aftermarket guard cost goes.

 

[mjac]

Similar in operation but chop saws are generally a fast spinning saw, often abrasive. Cold cut or dry cut uses a carbide tipped blade

What I have is a high rpm chop saw used for precision wood cuts, nothing heavy duty. Could you put a good Walter friction blade in it and get by pretty well? I mean I am an ace with the Metabo, but that might come in handy.

Thanks
mjac

 

[mjac]

You were wearing nylon athletic pants according to one of the early posts in this thread.
While “athletic pants” may in some cases be perfectly safe, generally “nylon ones aren’t, because many types of nylon fabrics are flammable, or meltable, and grinding creates sparks which can cause clothing to catch on fire, or melt, neither of which is pleasant, or safe.
If you want to wear “stretchy” “athletic pants”, while grinding, buy ones that are 100% cotton, or close yo it, and cut iff a piece of fabric from the cuff and do a burn test to make sure the fabric won’t melt of go up in flames.
There are also FR rated cotton sweat pants available that are treated specifically to prevent combustion.
As for removing the guards, (and the side handle), this is not necessarily safe, but the newer skinnier brushless grinders some manufacturers make, including Metabo, have a smaller diameter and would be easier to grip and maintain control of when being used in an awkward place without guards.
These grinders are also available with paddle switches, which would be even safer if you remove the safety guards.

Generally,
No safety system or component makes something inherently safe, or provides 100% safety, or even close.
Most user safety recommendations and usage instructions, also don’t provide 100% safety, but those instructions do help minimize injury or prevent injury in the case that something goes wrong.
Proper attire, and “grooming”, also helps prevent injury. (Ie. Long hair that can get grabbed by a grinder, and loose clothing that can as well).
Properly stored and safely aged grinding and cutting discs can also come into play, and may help prevent issues as well, along with having potential safety features built in, such as discs that get slightly thinner towards the center, to help prevent binding. (I forget who makes/made these discs).

If you follow the regular proper safety procedures, such as an angle grinder with a cutting guard, using the grinder with the discs cutting in the proper direction, preventing pinching of the cut material, having the cutting disc facing away from you while cutting, having a proper grip on the grinder, etc.,
You can use the shittiest discs imaginable, ones that might easily shatter, just with a little side loading, and there is likely a 99.9% chance you will not get injured making a cut, even with those ****** discs.
For all your claims about “knowing what you were doing”, everything you have said about what you were wearing, and how you were using the grinder, seems to indicate you don’t actually understand safe grinder use.
Grinder wheels spin around, so the linear direction one side is going, is going to be opposite to the linear direction of the opposite edge, a grinder guard can mostly prevent this
From being a safety issue, but if you remove the guard, then an errant touch on the wrong edge that is left exposed can cause the grinder to force itself in the opposite direction than what you might be expecting, and this is worse when cutting in an enclosed space, since the grinder can “bounce around”, like a pinball, once control is lost.

If you need better visibility in an enclosed space, maybe buy some mirror acrylic off cuts from a plastic supplier, and makeup mirrors for better view in the enclosed space.
Arbortech also makes a clear polycarbonate guard for use with their carbide tipped carving blade, and the guard is designed to be retrofittable to smaller grinders. The polycarbonate should be capable of protecting the user from a shattered wheel, and is designed do that cut depth can be limited.
It’s also fairly cheap as far as aftermarket guard cost goes.

Or you can just wing it…

Thanks
mjac

 

[KnurledNut]

Well, I bought some Makita cutting discs that are supposed to be good, tried them today and they are garbage. The Warrior cutting discs were better, smoother and wore better. Got disenchanted with friction discs and ordered a Lennox MetalMax metal body diamond encrusted blade. We will see how that works out…

Edit: Just found out how slow the Lennox MetalMax is, there is no way. Have to figure out which Walter to buy.

Thanks
mjac

That’s surprising. I don’t think I have used those particular ones, but I have never had any issues with Makita abrasives in general.

Did your grinder get dropped during the accident? Might not hurt to check it for runout. Highly unlikely but it would just take a second to check it. If it did hit the floor, I’d also run it without a disc and check for vibration. Even just a broken fan blade can give one a death rattle.

 

[Bad Habit]

What I have is a high rpm chop saw used for precision wood cuts, nothing heavy duty. Could you put a good Walter friction blade in it and get by pretty well? I mean I am an ace with the Metabo, but that might come in handy.

Thanks
mjac

Can you find metal cutting blades for a wood saw, probably. Check the RPM ratings. Would probably ruin a good chop saw with all the grit and **** it will leave behind. So much for "precision wood cuts".

 

[mjac]

That’s surprising. I don’t think I have used those particular ones, but I have never had any issues with Makita abrasives in general.

Did your grinder get dropped during the accident? Might not hurt to check it for runout. Highly unlikely but it would just take a second to check it. If it did hit the floor, I’d also run it without a disc and check for vibration. Even just a broken fan blade can give one a death rattle.

Maybe it is just me, I saw a test that they tested good and expected a pretty efficient, durable wheel, was cutting nothing major just some 1/8” - 1” angle iron and it dragged, had no feel, was slow, it just wasn’t cutting.
Yeah, the grinder dropped into my leg and did a good job. I think the grinder is okay, it feels alright.

Thanks
mjac

 

[mjac]

Can you find metal cutting blades for a wood saw, probably. Check the RPM ratings. Would probably ruin a good chop saw with all the grit and **** it will leave behind. So much for "precision wood cuts".

That is what I am afraid of, I want one little chop saw set on the side to do just precision wood cuts. Guess I better leave it alone.Maybe pick up another one somewhere…

Thanks
mjac

 

[whateg01]

That is what I am afraid of, I want one little chop saw set on the side to do just precision wood cuts. Guess I better leave it alone.Maybe pick up another one somewhere…

Thanks
mjac

Maybe buy a saw meant for cutting metal?