Quote Originally Posted by randyr View Post
I have a 4" hole saw and some 16 gauge steel. Could I just cut a disc, drill a 5/8" hole to fit my angle grinder the dimple it a bit and make it a little concave?
That angle grinder will be too fast - mine runs at 11,000 rpm - and will end up burning. The hole saw might come apart at the weld. I would be using my big Hitachi grinder/polisher which runs 600-3600 rpm and probably at some speed around 2000 or where ever it 'felt right'.