grinding concrete floor - cup wheel

[hetkind]

The concrete floor in my mechanical room is slightly off grade in a few spots, I just need to do a little grinding so all the water will drain to the floor drain, probaby no more that 1/4" over a few square feet.

To do this I got a silicon-carbide cup wheel, in a coarse grit, also called a snagging wheel.

Normally with a angle head grinder, you hold the flat or recessed wheel at a angle to the work piece, but as I recall with a cup wheel, you can grind flat...

Can anyone verify that a cup wheel on an angle head grinder can be used with the full surface of the cup on the workpiece?

Thanks,

Howard

 

[Sokoloff]

If you can get it to mount in the grinder and expose the whole face (bottom) it will work. Those should be used flat. The cups from my surfacing grinder won't fit my angle grinder (5" vs 4.5" IIRC), so I can't test it out, but I can tell you that the surface grinder uses the whole cup and uses it flat.

 

[hetkind]

thanks...that is exactly the information I needed...the wheel I got has a 4" bottom diameter, a 5" top diameter, so it should fit my 4.5" angle head.

I will try it tomorrow when the snow stops.

Howard

 

[WinFred]

it's a planer yur looking for...

I haver a really old version of this... hooked to a shop vac with a HEPA filter it's virtually dustless...

http://www.makita.com/en-us/Modules/Tools/ToolDetails.aspx?ID=316371

also have this one...

http://bosch.cpotools.com/grinders_and_metalworking/concrete_surfacing_grinder/

there is a difference between grinders and planers... I believe you'd be happier with a planer.. slower but more gooder finished product..

 

[hetkind]

for a single use of a few square feet, I should be OK with the angle head grinder and a cup wheel...and the cup wheel in an improvement over a regular depressed center wheel.

Howard

 

[hetkind]

Well, tried the cup wheel and the angle head grinder.

After a few minutes of grinding, the grinder got hot, started smoking and made crunchy noises. So mailed it off and another dead DeWalt power tool the nearest repair facility and will try this again, but with a 9" grinder instead of a 10 year old 4.5" grinder...Will stop by the tool store today.

Howard

 

[Oak]

I rented a machine from the local tool rental. My concrete was not finished properly and this unit did a good job. I think it was about $200 for the weekend with the stones that you have to purchase.

 

[hetkind]

I rented a machine from the local tool rental. My concrete was not finished properly and this unit did a good job. I think it was about $200 for the weekend with the stones that you have to purchase.

And how did the job come out? must have been a lot of dust...

Howard

 

[Oak]

There was no dust. You keep the floor wet and it did a good job. The machine can be seen in the first picture. My floor was not finished properly and I was going to use Wolverine epoxy on it so I wanted to do whatever I could to make it look good. Then I read the directions on their product and the floor must feel like sandpaper. It all worked out in the end. After I used the floor grinder I used muratic acid on it and my floor has been down for almost 1 year with no problems. It took a complete day to do my 1600 sf floor.