# Grinder not best tool to cut concrete?



## Red Squirrel (Jun 29, 2009)

I recently bought a Dewalt 4.5" grinder and bought a masonry cut off disc. I tried to use it to cut some slits in a cement slab so it can make some easy break points once I get out the jackhammer. It was barely making a dent in it, and the blade would just start getting loose in the tool and turning freely. Is there a proper way of doing this? I was expecting to go in like an inch or so, and I did not do any more damage to the slab than if I took a rock and scraped it against it. Could I have been doing something wrong? Or is this just a very long process?


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## oh'mike (Sep 18, 2009)

You have the retaining nut on wrong--flat side down --

Also, Get a diamond dry cutting blade--They should be around $10-- and will last a long,long time--

The abrasive cut off wheels cost more in the long run because they wear out so quickly.

Harbor freight has a three pack of diamond blade for about $20 I only need about 3 a year and they do a lot of work in that year.---Mike---


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## Red Squirrel (Jun 29, 2009)

Hmm could it be I don't have the right blade type? I tried the nut both ways. I could try to stick a piece of copper wire or some other material to give it "grip" but that will probably throw it off balance. I was using the supplied tool to tighten it.


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## oh'mike (Sep 18, 2009)

Post a picture of the shaft and flanges---see if one has a raised ring that goes into the hole on the blade.

Some brands use a reversible flare on the shaft--see if yours is reversible.


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