Cheap grinding disc warning

I bought some Davidson brand 4 1/2" grinding discs from Habor Freight. The first one, used very little, flew apart violently. Fortunately no pieces hit me. I was using it outside and have only found one piece, maybe 1/4 of it. The other 5 went in the trash. I had a similar experience with some elcheapo cut off wheels a friend gave me, first one grenaded and I pitched 3 dozen of them.
I used to use Bril-cut or Makita but since our local farm store got ruined by becoming Runnings, I can't get either here in town.

I am not exactly sure what you are using, but I have been buying these for a long time, and they work great. I buy them 100 at a time.

http://www.ebay.com/itm/100-4-5-x7-...els-40-Grit-/270664732527?hash=item3f04e00f6f

That's no good!
I've been using HF cut off discs for my whole build though. Only had one break on me and that was my fault cause i got it bound trying to turn it too tight during a cut. Maybe check your grinder and make sure the discs are seating flat and centered...
good luck

i'm real picky when it comes to grinding disc and i only buy sait #20063 the ones that don't have a nut on them. the ones like ron posted are good but not for what i do. glad you wasn't hurt.

RPM said:

I am not exactly sure what you are using, but I have been buying these for a long time, and they work great. I buy them 100 at a time.

http://www.ebay.com/itm/100-4-5-x7-...els-40-Grit-/270664732527?hash=item3f04e00f6f

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The ones I had were the hard kind. I have no issue with HF flap wheels, so far.
The Davidson didn't have the threaded center and it was a tight fit on the arbour I use. The poor fit should have been a red flag to the quality.
I have tried various cut off wheels and find the cheaper ones tend to go away a lot faster. Although the really expensive ones are a waste of money too. The $1.99 Dewalt ones last real well. The Bril-cut were the best, inexpensive and lasted real well. I only use the thin-cut ones.

I buy the Sait 3" thin kerf for my die grinders and Walters 7" for my big angle grinder.
When the 7" wear down to around 5" I put them on my small angle grinders.
Talking about small angle grinders, Lowes has Bosch 4" angle grinders in a two pack for $90, heck that's $45 a piece for a quality tool.
These type of wheels are inherently dangerous anyway and not buying the best is inviting disaster. That said, I have cut through my leather glove, when the blade exploded and damaged a knuckle or two.
The failure is my own for getting them in a bind.
I know all of us have the guards on our power tools too. (lol yea right

i like sait on my cut off wheels too, i run the 3"x1/4"x1/16" but have had them break as well. if one of my grinders hits the floor the wheel goes in the garbage, i just don't chance it. we also use the sanding pads that have a backer wheel and spiral lock nut. if the edge of the wheel gets a chip it goes by by as i had one jump and wrap my shirt up to my chin.

Harbor Freight discs are dangerous and not much better than a Ritz cracker anyhow. I like the Dewalt discs.

Bill in SC

I use Campbell Hausfield from Wally World most of the time. Never had a problem with them. Also use some from the parts house, can't remember the brand but they are a major welding supplier.

Yep, I have been buying individual discs from my local HW store and really like them. Saw the pack of 10 I think for Harbor Fraud and bought it since it was on sale and the cost of 2 of the discs I normally get. First one lasted about 3 minutes trying to grind on a weld. Didn't think much of it, put the second disc on and decided to put on my face shield instead of just my glasses ( listen to the voices in your head). That 2nd disc came completely apart about with about quarter wear. Showered my shield with disc chips. Walked over to the remaining pack and tossed em'.

As far I I'm concerned, if it says 'Made in China', it ain't going home with me. A buddy nearly lost a finger and got a pretty big gash on his arm from a 4 1/2" cutoff wheel that flew apart, made in China! Not saying that can't and doesn't happen using other cutoff wheels but I've heard too many stories of it happening with Made in China stuff! No thanks!

26Troadster said:

if one of my grinders hits the floor the wheel goes in the garbage, i just don't chance it.

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Same here!

iSore

These say California on them, but I think just the label was made there.

To all of my good friends on RRR. Do not cheap out on grinding wheels and cut-off wheels. Please.

The edge of a 4.5" grinding or cut-off disc is moving at 147 miles per hour at free speed. (11,000 rpm) Under load, it's about 130 mph.
The edge of a 9" wheel at free speed (6,600 rpm) is moving at 177 miles per hour. Under load it slows to about 160 mph.
You don't want any part of that thing coming off and hitting anything, at all. Plus, the quality wheels that cost more, last longer! They usually balance better, which means they grind smoother, don't make your hands as sore, and aren't shaking your grinder apart.

Flap wheels probably aren't as risky because if only a flap comes off, it won't do much. Even still, they have about half of the abrasive material that a good disc has. (They last half as long.)

The guards... I've used my share of grinders without guards, but really, the guards aren't there because we're too stupid or careless to keep from putting our fingers in the wheel. The guards are there as a scatter shield. It keeps junk from getting lodged in your junk when a wheel comes apart.

Even the best wheels can come apart, and it doesn't matter how experienced you are. It happens. Use the guard.

8literbeater said:

The guards... I've used my share of grinders without guards, but really, the guards aren't there because we're too stupid or careless to keep from putting our fingers in the wheel. The guards are there as a scatter shield. It keeps junk from getting lodged in your junk when a wheel comes apart.

Even the best wheels can come apart, and it doesn't matter how experienced you are. It happens. Use the guard.

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This. Yes.

Old Iron said:

.
I know all of us have the guards on our power tools too. (lol yea right

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I sure as heck do.
I like my fingers and eyes

And after looking at the picture, I know why I never, ever get my face in the same plane as the disc.

I never had one come apart. Used all kinds of discs. I wear eye protection and leave the guard on. I've learned not to jam the disc into unreasonable positions. Since my thumbs have worn out and I can't use a sawzall I do all my cutting with a 4 1/2" angle grinder with thin cut off wheels.

Guards are important, as are quality tools, and cutting parts are tools. Discs, blades, whatever. I have noticed that HF discs don't last as long, but I have blown up most any brand if I was treating it wrong.

[dddThat said, when I was a millwright, one of the funniest (sadistically so, I admit) things I ever saw was when a coworker sit on his 4" grinder. It was a Black and Decker with a squeeze trigger on it. No real harm fortunately. [ddd

Be careful where you leave your tools while working on a project.

Guards will for the most part protect you...... but, co-worker was
using one in a small shop we were using, blade shattered then KABOOM
when the dust cleared we saw half the blade stuck in a electric fork trk
battery another guy was working on.....the battery did not survive
so if you have friends helping.......make sure they are aware or behind
the missle..............

I've never had a HF wheel explode that didn't get dropped first or twisted when grinding. BUT, they do wear out very quickly compared to a quality wheel. I can usually cut 3-4 times more metal with a good wheel. Cheap does not usually equate to economy.