I use a 90 for sharp, 60 for flat, I like to call this semi-flat, and a fine tooth hobby hack saw (30 to 40 teeth for inch) for absolute flat checkering. to finish the absloute flat I just touch the checkering with a 60 to smooth up the lines. I usually use the fine tools from start to finish but that's just me - I'm in no hurry. --- John Can.