Hello to u all.

I use a wide decorative cutting blade and do two too three runs for the required width, this then does away with having to chip away thereby leaving a smooth surface.

just my little tip.

cheers

MikeW

Guys, thanks for your input and sorry to be just replying now.

The customer actually decided to get us to cut a square trench and made up a grate with legs to go into it.

It worked out very well.

I've done similar jobs, had great success just stacking blades 3/4" - 1" wide and milling out the concrete.  a hand grinder can fix a few blemishes.

Kinda curious how this job turned out and how you tackled it?

I agree with Mark, multiple cuts or use multiple blades with spacers and Chip out. Cut to depth a bit below the specified depth to limit any bushing. 

Jody,

I have tried doing this many times. how i have found the best way to do it is to make multiple cuts to the 1 1/2" depth and then chip it out. usually we cut to 1 3/4" depth. once the grating is in place we can then adjust it by chipping more out if it is high or applying a non shrink grout if it is low.

If it's not an extreme amount of footage, can a skil saw be modified with a piece of angle iron  on it to do your task? Allowing you a nice surface for the grate. We had skil saws with water set up on them to keep the dust down at an old company I used to work for. Make that cut then do the top cut last.

I am quoting a job to cut some trenches for water drainage. I will need to prep the trench to accept a steel grate that sits flush to the floor. The grait will require a 1 1/2" square notch be taken out of both sides on top. Cutting the top 1 1/2"is no problem, But cutting the side 1 1/2" from inside the trench is a real pain in the butt. That is if you want to be accurate and have the grate sit flat without moving.

Normally I would solve this problem by cutting a straight trench and attaching a piece of angle on the insides for the grate to sit on. But this application is going to have heavy traffic and also the owner wants it to match the existing grating.

There has to be an easier way to cut these notches out.

Any ideas guys?