OMT blade to cut cement board

[stickshift]

I need to cut some installed 1/2" cement board, and access is limited, so I'll have to use an oscillating multitool. Need to cut 2 linear feet. What's a good blade for this that isn't going to get dulled almost immediately?

 

[mike93lx]

I think you can get diamond coated blades, but I would take the dullest one I have on hand and use a grinder cutoff wheel to cut some rough teeth into it to see it that does it.

 

[cgrutt]

I have a diamond grit grout blade for my Fein that has held up fairly well (should be replaced though) but haven't used it on cement board. Would a carbide scoring tool work?

 

[gizardlizard]

Use a diamond blade on your multi tool. Score and snap like drywall. Cut thru the fiberglass cloth on the back with a utility knife. Super quick and easy.

 

[mike93lx]

Use a diamond blade on your multi tool. Score and snap like drywall. Cut thru the fiberglass cloth on the back with a utility knife. Super quick and easy.

Since access is limited, I was assuming this is a cut to be made in place, so snapping wouldn't work

 

[stickshift]

Since access is limited, I was assuming this is a cut to be made in place, so snapping wouldn't work

Correct. Installed on floor, with very limited access, so no ability to score and snap.

 

[The Cobbler]

look for carbide oscillating blade .

 

[gizardlizard]

Correct. Installed on floor, with very limited access, so no ability to score and snap.

My bad. Missed that part. Diamond blade on multi tool will still work. Just keep going back and forth.

 

[gahrajmahal]

I need to cut some installed 1/2" cement board, and access is limited, so I'll have to use an oscillating multitool. Need to cut 2 linear feet. What's a good blade for this that isn't going to get dulled almost immediately?

I’d stay away from Harbor Freight brands. I have had decent luck with Home Depot, I think Diablo is the brand. You can even use a regular toothed blade, but you might need a couple.

If it’s going to get covered up and you can reach it with a cold chisel you might be able to just hammer it out.

 

[stickshift]

Thanks everyone. Got 'er done.

look for carbide oscillating blade .

That's what I used.

For anyone with similar issue who stumbles on this thread in the future, I used the Dremel MM485U blade, available at HD.

Dremel Universal 1-1/4 in. Carbide Flush Cutting Oscillating Multi-Tool Blade (1-Piece) MM485U - The Home Depot

Visit The Home Depot to buy Dremel Carbide Flush Cut Blade MM485

www.homedepot.com