This is THE BEST tool you will own!!

Try both sides and see which gives the best result.

Also, square up your inserts!! To do this, color the entire surface of the insert with a black marker (this is to see any high/low spots). Then, shave a bit off and check your insert. Once all of the black is gone you're done! BTW, make sure your inserts are installed in a squared shaft before before you try to square them. I know, it's a no brainer...but you never know! lol

Once you're all done, you will notice that your groups are tighter! ALWAYS A PLUS!!