Cheap Discs and Angle Grinders

[Copymutt]

I tried to cut my thumb off once. Ran the disc across the back of the big joint.
Wonder how filet gloves would protect?

 

[mjac]

I haven't seen a black and Decker grinding wheel in years. How old was it? Grinding or cutoff? Fiber reinforced? Even "good" grinding wheels break if mistreated.

I don't quite understand why you had to unplug the grinder. If the wheel broke and was imbedded in your leg, the damage is done.

That said, this type of thing is why I hate when I see people advocating for removing safety devices.

Cut Off Wheels, neatly stacked and binded. Would have to check if they are fiber reinforced. The most dangerous thing about them that almost at the beginning of a cut the edges of the wheels would fray. I believe that is what happened here, the edges frayed and caught the edge of the metal as the cut was going over the top to go down the vertical leg.…BOOM, lightening fast kickback. The wheel did not break, the grinder kicked back violently, so fast I did not see it, into my thigh pants leg where the grinder and wheel proceeded to grind into my pants leg and thigh getting tighter and tighter, could not find the switch, finally sidestepped over and grabbed the plug out of the wall. Took about 15-20 minutes to untangle the grinder and the mangled disc out of the pants and thigh. Didn’t want to look at the leg so put an old HF disc in the grinder and finished up. Held my breath and looked at it inside. Wasn’t too bad, mostly superficial, but thought it was much worse. Very, very lucky that grinder could have landed anywhere.

Thanks
mjac

 

[mjac]

I tried to cut my thumb off once. Ran the disc across the back of the big joint.
Wonder how filet gloves would protect?

Wouldn’t want to find out…

Thanks
mjac

 

[PCustoms]

I believe that is what happened here, the edges frayed and caught the edge of the metal as the cut was going over the top to go down the vertical leg.…BOOM, lightening fast kickback. The wheel did not break, the grinder kicked back violently

Not sure this is a "cheap disc" issue, sounds more like they way you were cutting/grinder binding....

 

[M.Brane]

1st rule of grinding/cutting: don't get greedy. Let the blade do the work. Firm grip light pressure.

 

[M635_Guy]

I have had pretty good luck with Harbor Freight cutting discs and have seen tests of them where they did pretty well against name brands. For me, they held together, didn’t fray at the edges (like the Black and Decker), wore down evenly and were smooth and predictable. The one I finished up with was a well worn down (about 2/3 diameter) Warrior.
I am going to try all the top brands and see which one I like…

Edit: About 15 new Black & Decker cutting discs went into the trash.

Thanks
mjac

I cut up a cast iron tub 18 mos ago or so, and used both Makita cutting discs and a diamond cutting disc (can't remember the brand).

 

[Crazyjake8493]

80% of the cutting discs I have used in the last 5 years have been Harbor Freight - zero issues. Any disc will wreak havoc if you don't use them properly. Plan your cuts, know where the material will fall, twist, or bind. Most importantly, wear your PPE. (T-shirts and flip flops are not PPE)

 

[Crazyjake8493]

1st rule of grinding/cutting: don't get greedy. Let the blade do the work. Firm grip light pressure.

100%

Light pressure and anticipate where the material will fall or move toward as it's cut.

 

[KnurledNut]

I use these with my Makita cordless angle grinder. Get more cuts per battery life. I buy the 25 pk.
https://www.amazon.com/Makita-B-46143-Ultra-Cut-Off-Stainless/dp/B0199RA4UU?tag=atomicindus08-20

 

[whateg01]

Cut Off Wheels, neatly stacked and binded. Would have to check if they are fiber reinforced. The most dangerous thing about them that almost at the beginning of a cut the edges of the wheels would fray. I believe that is what happened here, the edges frayed and caught the edge of the metal as the cut was going over the top to go down the vertical leg.…BOOM, lightening fast kickback. The wheel did not break, the grinder kicked back violently, so fast I did not see it, into my thigh pants leg where the grinder and wheel proceeded to grind into my pants leg and thigh getting tighter and tighter, could not find the switch, finally sidestepped over and grabbed the plug out of the wall. Took about 15-20 minutes to untangle the grinder and the mangled disc out of the pants and thigh. Didn’t want to look at the leg so put an old HF disc in the grinder and finished up. Held my breath and looked at it inside. Wasn’t too bad, mostly superficial, but thought it was much worse. Very, very lucky that grinder could have landed anywhere.

Thanks
mjac

Honestly, it sounds misplaced blame. I believe any disc could have done whatever that one did in that situation.

Based on that, two things that it sounds like you were not doing. One, always if at all possible use the tool so that if the disc does catch it will pull away from you and not kick back into you. Second it sounds like you were not using both hands on the grinder. Anything that I'm doing where I am going to have to lean into the work at all gets done with two hands. I will use a flap disc sometimes one handed but I'm not really putting a whole lot of force on it when I do it that way. Mostly just to break edges and that sort of thing. If I'm going to be making a heavy cut, I'll be using both hands on the grinder.

 

[dnschmidt]

You'll notice nobody is recommending tool brands like Makita, DeWalt, Milwaukee.... they aren't known to make quality abrasives

Abrasive companies make good abrasives

coo in this particular case does play a role

This appears to be a common misconception. Just because it says Makita or DeWalt on it in no way implies that they make the disc. They are marketing companies. Pferd, Walter, SAIT, Metabo, 3m and companies that specialize in abrasives like Norton make the discs. The marketing companies are going to give the contract to the lowest bidder and I'm pretty sure don't give a damn if it slices your leg off. Pferd cares because abrasives and files are all they do. If their product sucked they would be out of business. Makita tends to pick quality Japanese brands for a lot of their private labeled stuff. For example their saw blades are made by Tenryu which is a top quality brand.

 

[Steve_P]

For 4.5", and larger, cutoff wheels, for a handheld grinder, all I use are the Lenox Metalmax wheels. Yes, they are slower cutting, but they are most likely not going to explode and disfigure you. I can spend another minute for my own safety. And I'm sure the best quality cutoff wheels are less likely to do this, but they will all explode when you put them in bending; they're only meant for a radial load, which is difficult to maintain freehand with a grinder.

 

[mjac]

Not sure this is a "cheap disc" issue, sounds more like they way you were cutting/grinder binding....

All i know is, brand new Black & Decker 4 1/2” cut off disc, went across top of horizontal leg of 1/8” 1 1/2” angle iron, came over the top to go down vertical leg which was in a large vise trying to keep disc on the outside and feather into the down vertical cut, violent kick back , grinder and disc go into leg.
Thought it was a freak accident, made that cut before quite a few times. Untangled everything, little blood dripping down leg, put in a new Black & Decker disc, tried to feather even more, grinder violently kicked back again into same leg ( see two leg grabs) Untangled everything again, afraid to look at leg, POed now, put in a well used HF cut off disc and finished the cut…
Went inside to look at the damage, not too bad, thought it was worse.
But you could be right.

Thanks mjac

 

[mjac]

1st rule of grinding/cutting: don't get greedy. Let the blade do the work. Firm grip light pressure.

Thought I had it down, gradual progress, then BOOM.

Thanks mjac

 

[mjac]

I use these with my Makita cordless angle grinder. Get more cuts per battery life. I buy the 25 pk.
https://www.amazon.com/Makita-B-46143-Ultra-Cut-Off-Stainless/dp/B0199RA4UU?tag=atomicindus08-20

This is what I just bought…

 

[mjac]

Honestly, it sounds misplaced blame. I believe any disc could have done whatever that one did in that situation.

Based on that, two things that it sounds like you were not doing. One, always if at all possible use the tool so that if the disc does catch it will pull away from you and not kick back into you. Second it sounds like you were not using both hands on the grinder. Anything that I'm doing where I am going to have to lean into the work at all gets done with two hands. I will use a flap disc sometimes one handed but I'm not really putting a whole lot of force on it when I do it that way. Mostly just to break edges and that sort of thing. If I'm going to be making a heavy cut, I'll be using both hands on the grinder.

See response to @PCustoms above and make judgement.
100% right about this, should have been cutting with sparks flowing at me…
Two hands are always on the grinder, powerful tool

Thanks
mjac

 

[Junkman]

You said that you pulled the plug to stop the tool. If you use a foot pedal switch to activate the tool's power, all it would take is to remove your foot from the switch, and the tool would stop. I had a large grinding wheel that I always approached with caution. I set it up with a foot pedal and felt a lot safer knowing that if anything happened, I could stop it by removing my foot from the pedal. I use the Linemaster (Woodstock, CT) brand of foot pedal switches.

 

[mjac]

This appears to be a common misconception. Just because it says Makita or DeWalt on it in no way implies that they make the disc. They are marketing companies. Pferd, Walter, SAIT, Metabo, 3m and companies that specialize in abrasives like Norton make the discs. The marketing companies are going to give the contract to the lowest bidder and I'm pretty sure don't give a damn if it slices your leg off. Pferd cares because abrasives and files are all they do. If their product sucked they would be out of business. Makita tends to pick quality Japanese brands for a lot of their private labeled stuff. For example their saw blades are made by Tenryu which is a top quality brand.

Saw some good tests with Makita cut off wheels, but Walter, Pferd, Lennox ate supposed to be better. Not familiar with SAIT and Metabo discs but people have recommended them. I assume Metabo would be good.

Thanks
mjac

 

[mjac]

For 4.5", and larger, cutoff wheels, for a handheld grinder, all I use are the Lenox Metalmax wheels. Yes, they are slower cutting, but they are most likely not going to explode and disfigure you. I can spend another minute for my own safety. And I'm sure the best quality cutoff wheels are less likely to do this, but they will all explode when you put them in bending; they're only meant for a radial load, which is difficult to maintain freehand with a grinder.

That is the way I am leaning right now, for all of the same reasons, safety the top priority. Going to try all the top brands and decide.

Thanks
mjac

 

[mjac]

You said that you pulled the plug to stop the tool. If you use a foot pedal switch to activate the tool's power, all it would take is to remove your foot from the switch, and the tool would stop. I had a large grinding wheel that I always approached with caution. I set it up with a foot pedal and felt a lot safer knowing that if anything happened, I could stop it by removing my foot from the pedal. I use the Linemaster (Woodstock, CT) brand of foot pedal switches.

I never knew/thought about that. Thought because the Metabo had a switch and not a paddle ( and the switch is a PIA) I was stuck with it. After what happened I will look into “Linemaster” right now.

Edit: They can be pricey, I asked them to recommend one that would do the job and not break the bank.

Thanks
mjac

 

[MongoTA]

After what happened, I would never put another Harbor Freight disc on a grinder, only the top of the line, best.
mjac

I've picked up a few things at HF over the years, but my rule is that if it can fail and kill/maim me, no thanks.

I use Walter cutoffs.

Glad it's not worse, and I'm also glad I just bought a new full face shield with full shield frame last week! On occasion I feel like it's a bit much especially when making one small metal cut, but I've gotten really good about always wearing an apron. I keep it handy, hung on a nail, right next to my metal table.

 

[KnurledNut]

That is the way I am leaning right now, for all of the same reasons, safety the top priority. Going to try all the top brands and decide.

Thanks
mjac

Another worth checking out, Flexovit Razorblades.
https://www.flexovitabrasives.com/razorblade-cutoff-wheels/
I have them for my 6".

 

[mjac]

I've picked up a few things at HF over the years, but my rule is that if it can fail and kill/maim me, no thanks.

I use Walter cutoffs.

Glad it's not worse, and I'm also glad I just bought a new full face shield with full shield frame last week! On occasion I feel like it's a bit much especially when making one small metal cut, but I've gotten really good about always wearing an apron. I keep it handy, hung on a nail, right next to my metal table.

Can’t put down HF discs, they have performed pretty well, much, much better then Black & Decker, but after seeing what can happen only the best is going on that grinder. Going to try Makita, Walter, Pferd and Lennox and decide. Had goggles, got banged right in the forehead, got a full coverage shield, goggles won’t fit over new glasses, been leaving them off, have to go back and use the bifocals and adjust to them to use the shield and the goggles.
Nobody likes my baggy nylon athletic pants.

Thanks
mjac

 

[mjac]

Another worth checking out, Flexovit Razorblades.
https://www.flexovitabrasives.com/razorblade-cutoff-wheels/
I have them for my 6".Not familiar with them, that is Metabo discs, SAIT and Flexovit. Might try them after the Makita, Pferd, Walter and Lennox. One of them has to be good…

Thanks
mjac

 

[KnurledNut]

Thanks
mjac

https://www.amazon.com/Flexovit®-RA...ed-Cut-Off/dp/B0FD474CW4?tag=atomicindus08-20

 

[mjac]

https://www.amazon.com/Flexovit®-RAZORBLADE®-Aluminum-Reinforced-Cut-Off/dp/B0FD474CW4?tag=atomicindus08-20

You put them up there with Walter, Lennox, Pferd and Makita?

Thanks
mjac

 

[The Cobbler]

I try real hard to wear a face shield & leather apron when cutting or grinding. sometimes I get negligent but as I get older it seems less so

 

[L.Cheapo]

Glad it wasn't worse, OP.

My personal policy on abrasives and PPE is if 3M makes it, I buy the 3M. Hasn't let me down yet.

 

[mjac]

I try real hard to wear a face shield & leather apron when cutting or grinding. sometimes I get negligent but as I get older it seems less so

I will never forget that grinder and wheel digging into my nylon athletic pants and leg While I froze for 3-4 seconds before shifting over and pulling that plug. Grinder kicks back violently into leather apron, what happens?

Thanks
mjac

 

[mjac]

Glad it wasn't worse, OP.

My personal policy on abrasives and PPE is if 3M makes it, I buy the 3M. Hasn't let me down yet.

3M, Lennox, Pferd, Walter, Makita, which is your choice?

Thanks
mjac

 

[seber]

I will never forget that grinder and wheel digging into my nylon athletic pants and leg While I froze for 3-4 seconds before shifting over and pulling that plug. Grinder kicks back violently into leather apron, what happens?

Thanks
mjac

The disk will bounce off of hard leather.

 

[YesIHaveAHammer]

Manufacturers recommended that discs be stored in a certain temperature and humidity range, to avoid weakening of the bonding resin through moisture absorption and expansion. The details vary from essentially "keep them in the house" to "don't let them freeze".

 

[rockbaron1]

While there are cheap grinding/cutting discs out there I find most accidents with grinders are the result of improper use/technique. I’ve had good and bad cutting discs come apart before and it’s always the result me doing something I shouldn’t have.

 

[drokihazan]

I use Benchmark and Hercules flap wheels mostly. But I absolutely wear jeans, boots, a carhartt jacket, and a face shield when I grind. It's not at all a big deal to throw some PPE on, and it's a lot more convenient to have all my fingers and toes attached to my body where they belong.

 

[Nobody-named-Olli]

And bonded discs/wheels have an expiration date for a reason.


@mjac can you post a pic of those Black & Decker cut off discs?

Kind regards,
Olli

 

[dnschmidt]

Another worth checking out, Flexovit Razorblades.
https://www.flexovitabrasives.com/razorblade-cutoff-wheels/
I have them for my 6".

Flexovit is a division of Saint Gobain the same company that owns the Norton brand. So, as you would suspect, Flexovit does make good stuff.

 

[mjac]

The disk will bounce off of hard leather.

Disc or grinder shaft if disc shatters on impact with the apron, will not dig into the apron and twist it?

Thanks
mjac

 

[MOS3522]

When grinding….good disks, safety glasses, face shield, gloves, ear protection, long sleeves tucked into gloves, long pants, fire extinguisher and a grinder with a paddle switch…not one of those switch on things. I hate grinding…but…

OP, hope your recovery goes well…

Get out of my garage! Yes that's my routine, face shield - proper pants - usually a welding coat. As for extinguisher, I suggest you track down a pressurized water or CO2 extinguisher. The ABCs filled with MAP will make a real mess of your space.

 

[KnurledNut]

Flexovit is a division of Saint Gobain the same company that owns the Norton brand. So, as you would suspect, Flexovit does make good stuff.

Yes and No.
There are two separate companies.
-The global Flexovit brand is owned by SG.
-Flexovit USA (Angola, NY based) operates as a separate entity, a privately held company. They manufacture exclusively in the USA and only distribute in the Americas (NY, CA, Mexico, Canada).

 

[mjac]

Manufacturers recommended that discs be stored in a certain temperature and humidity range, to avoid weakening of the bonding resin through moisture absorption and expansion. The details vary from essentially "keep them in the house" to "don't let them freeze".

Now, I will admit, these Black & Decker discs were stored inside a van under whatever conditions that existed in there, through whatever weather conditions that occurred and may have been older then I realize (had them laying around in case I needed them), but the Warrior discs that I was using and the one I finished up with after getting hurt, were in the same stack.

Thanks
mjac