Grinder not best tool to cut concrete?

Red Squirrel · 06-09-2011, 09:56 PM

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?

**oh'mike** · 06-09-2011, 10:19 PM

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---

Red Squirrel · 06-10-2011, 08:34 PM

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.

**oh'mike** · 06-11-2011, 08:29 AM

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.