Hey everyone, I am posting this topic on MYCNCUK because I have found this forum to be very helpful in the past. This topic might not relate to CNC's as such but I am sure you guys will have some answers for me. Recently I purchased an aluminium round bar with an inch wide diameter and 400mm in length. I reduced the diameter on one end down to 16mm using my friend's lathe. This was done so that I could fit the rod in my pillar drill chuck. I am currently using a 60 grit aluminium oxide sanding paper glued on the surface of the rod for my ultimate sanding drum.

The purpose of this sanding drum is to sand the inside of the bamboo poles I use for making bike frames. Now the sand paper that I glued to the aluminium surface has started to smooth out already after my first use. So I am tying this topic over here to get some advice really as I am not sure what I can do to the aluminium surface to make more like a filing surface. If aluminium is not a good surface for that then I can always buy a steel bar to do the job, but I absolutely have no idea what tool or method could make a shiny metal surface into something that is rough like a file. Any help would be appreciated greatly at this point as I am running out of options now . Thanks