CoilThread Inserts conform to the thread profile created by the STI tap. Whatever the Class of Fit of the STI tap (3B, 2B - Unified; 4H, 5H - Metric) is the Class of Fit of the finished thread profile after insert installation. It is recommended to use KATO STI cutting taps as ...
When cutting acrylic for applications where the edge will be visible and will need to be either polished or at least very smooth, it's absolutely imperative that you get the cut right the first time. It may seem that you could easily fix any roughness in the edge with a bit of sandpaper...