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View Full Version : Which angle grinder blade for cutting metal and concrete at the same time?



Ken Platt
03-22-2019, 9:34 PM
Folks -

I am going to be removing a bunch (maybe 8) of 60 year old basement windows, the kind in which the frame is embedded in the concrete. I've never done this before, but apparently the first step, after removing the sash, is to cut across the frame so you can pry it out with a crow bar. I'm looking for recommendations on which blade would make this cut easiest.

I have two angle grinders, one the standard 4.5 inch size (makita), and the other a monster 9 inch, 15 amp milwaukee. The bigger one is probably too heavy and awkward for this job, but I wonder if the weight would be an asset in cutting the bottom of the frame at least.

Also, if anyone's done this job, would this be a good job for which to get a Harbor Freight cheap grinder rather than use my nice makita which I got for power carving?

Thanks - Ken

Bruce Wrenn
03-22-2019, 10:07 PM
For actual cutting of the steel framework, my first choice would be the 4 1/2" with a Lennox diamond blade made for metal. Blade can be gotten at Lowes for around $15. Out last abrasive wheels 10 to 1 in my experience. Since you are only cutting a 1/8" cut , vs a 1/4" cut, takes half the effort and half the sparks. Because the HF comes with a 90 day no questions asked warranty, I would probably go with one.

Tom M King
03-22-2019, 10:32 PM
I don't use my good grinders for dirty, dusty cutting. Before we had HF's here, I'd buy the 29.95 ones from Walmart for such work, and they would last way longer than I ever expected them to.

Andrew Fleck
03-22-2019, 11:42 PM
Just get a mild steel cut off wheel for your 4.5” grinder. It shouldn’t be more than 4 or 5 dollars at your local hardware store. One should be plenty for that job. I would just use the Makita you already have.

Andrew Fleck
03-22-2019, 11:45 PM
Sorry I just read your post again. You might want 3 blades to be safe.

Tim Bueler
03-23-2019, 10:42 AM
Ken, I've replaced a few windows over the years. Here's another alternative to cutting out aluminum frame windows. I welded hooks to a couple of vise grips. Remove the glass and clamp the vise grips onto the frame on opposing sides. Using short lengths of chain connect the two vise grips with a come-a-long or chain binder in between. Start cinching it up and it will pull/collapse the frame in. No dirt/dust/mess. Sometimes, on stubborn frames, you may have to reset one or the other vise grip as they can pull a chunk right out of the frame, but I've never had one that didn't eventually succumb. No disturbance to surrounding trim and I've used this method on both wood and masonry surrounded window frames.

Good luck! Nasty job!

Ken Platt
03-24-2019, 10:38 PM
Thanks all. Tim, your way sounds neat but these windows are only 13 inches high, so I'm not sure how I'd get in there with the vise grips and the rest of it. Do you have a picture? I am hoping it'll go quickly to just cut and lever out the pieces, but it never hurts to have a backup plan in case this is harder than it looks.

Ken

Tim Bueler
03-25-2019, 10:21 AM
Thanks all. Tim, your way sounds neat but these windows are only 13 inches high, so I'm not sure how I'd get in there with the vise grips and the rest of it. Do you have a picture? I am hoping it'll go quickly to just cut and lever out the pieces, but it never hurts to have a backup plan in case this is harder than it looks.

Ken

Sorry Ken, I don't have pictures. You're right, my lash up wouldn't fit in that space, I imagine by the time you got 2 vise grips and small chain binder in there it would take ~30" or so when you figure there has to be room for the frame to collapse. Looks like you're stuck with the cut and pry method.:(