On Friday, July 14, 2017 at 2:37:00 PM UTC-4, wrote:
I compared a Pferd 40 grit flap disc made for stainless steel to a
Cubitron II flap disc made by 3M. The Cubitron cuts at least 3 times
faster than the Pferd disc as well as wearing better than the Pferd
disc. I am truly impressed with the Cubitron II flap discs and will be
buying them now instead of the Pferd.
Eric

I ordered a cubitron ii flap disc , a 4 1/2 by .25 and a 4 1/2 by o.45 cutoff disk. And today put them to good use. At the local scrap yard I picked up four pieces of 3 by 4 square tubing that had a 3/4 inch thick plate welded on one end. The plate was welded on two sides. I used the .25 thick disc to remove most of the weld and then used the o.45 cutoff to get most of the remaining weld. A BFH hammer broke the remaining weld.

The cubitron disks worked very well. Cut fast and did not require a lot of pressure. Much easier to control when you do not have to apply much pressure.

The medium priced 4 1/2 inch Harbor Freight angle grinders are pretty good, but the disks from HF can be worthless.

Dan