I wonder what type of stainless that frame is made of? Is it magnetic? (ie: put a magnet near it)
I would imagine the SS used shouldn't present a problem machining or polishing.
This is (likely) 304 I'm using for a bracket to secure my water main against the house. 1/4" hole with a quick chamfer then a slight polish with the deburr wheel. That pin hole of yours looks like the tool used to pretty the hole chattered and they said "fuck it"...

I would imagine the SS used shouldn't present a problem machining or polishing.
This is (likely) 304 I'm using for a bracket to secure my water main against the house. 1/4" hole with a quick chamfer then a slight polish with the deburr wheel. That pin hole of yours looks like the tool used to pretty the hole chattered and they said "fuck it"...

