Tiger
Member
I have cracked 2 acrylic blanks in the last week. One was a hole of 35/64 inches, the other was 37/64 inches. In both cases i sequentially drilled up to these sizes, so i start with a smaller drill bit and work my way up. One crack occurred in the drill press, the other in the lathe. Speed was 500 rpm, feed was slow. In both cases the drill bit seemed to grab the blank and cause the crack. Bits were sharp, only thing i can think of is to turn the blank round so there's more support, any suggestions? In one of the cases mentioned above, the proper size hole was 33/64 but with painting inside the blank and also painting the brass tube i needed to open it up, tried sanding the hole but progress was very slow.