Safely use a straight (Type 1) metal cutoff wheel in angle grinder

angle-grindercuttingpowertoolssafety

I have a Ridgid angle grinder and a metal cutoff wheel.

On page 7 of the manual it states:

Use ONLY Type 27 depressed center grinding wheels (such as the one provided with this product). NEVER attach a Type 1 straight or cut-off wheel to this angle grinder. Use for any other purpose is not recommended and creates a hazard, which will result in serious injury.

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After reading some online forums, asking some contractor friends, and watching YouTube videos it seems that everyone simply uses a Type 1 wheel to cut metal and move on with their life.

PS: I won't acknowledge the countless people that use an angle grinder without the guard. I will absolutely be putting the guard in the correct position.

As far as I can tell I just have to reverse the clamp nut and it securely holds the Type 1 cutoff wheel in place.

Am I using the wrong tool or wrong cutoff wheel or are there simply so many more Type 1 wheel accidents that companies just try to distance themselves from Type 1?

Even the cutoff wheel packaging says "for use with angle grinders" and has a picture of an angle grinder.

Important: I am trying to solicit authoritative answers which can properly explain why one should not use a Type 1 disc. I do not wish for polling answers such as "I've done it so you're fine".

Best Answer

I think I have enough research to make an answer to this. I believe it comes down to the guard available for this tool and it not meeting the requirements for a "Type 1" cut off disk.

This Ridgid forum has what is supposed to be a quote from Ridgid:

The RIDGID R1001 Angle Grinder has an included type 27 guard and is certified to Underwriters Laboratories (U.L.) product safety standards. U.L. requires only type 27 depressed center grinding wheels be used with type 27 guards. Type 1 straight or cut-off wheels have no depressed center posing a safety concern to the operator when connected to a type 27 guard. In no circumstance should a type 1 straight cut-off wheel be used with a type 27 guard. Please contact RIDGID customer for further assistance: 866-539-1710.

This is for a different model, but it does show that they do limit the wheels on their tools based on the guards.

I also found this PDF from an abrasives saftey site that shows an enclosed guard is used for cutoff wheels:

Angle grinder guard types

I also found a Makita manual that shows an optional enclosed guard for cut off wheels (#13):

Makita diagram

And here is that product sold seperately:

cut off guard

So, all of that points to the guard being the "breaking point" for the type 1 disc support. This is probably because the company had some legal issue in the past so they have decided to officially not support that type of disk with their tools while other brands are happy to sell different guards (speculation alert).

I guess what it comes down to is trusting the included guard to contain the explosion of a cracked type 1 disc.

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