Debate: Should you dial in feeds and speeds on the machine or on paper first?

Overheard two old timers arguing yesterday at a shop in Detroit, one swears by doing all the math on paper before touching the control while the other just tweaks everything on the fly at the machine. The paper guy said it saves him from scrapping parts and the on-the-fly guy said he gets done faster without overthinking it. Which side do you lean toward and has one way ever burned you?

2 comments

2 Comments

evanpalmer21d ago

Ngl I dialed in a part once without checking feeds first and blew a $400 endmill in under 10 seconds.

mason20921d ago

That bit about blowing a $400 endmill in under 10 seconds is exactly why I side with the paper guy. I've been machining since the late 80s and I can't count how many times I saved a job by sitting down first with a calculator and a feeds and speeds chart. The on-the-fly method works great until it doesn't and then you're out real money and possibly a whole work shift. What a lot of younger guys don't get is that the math gives you a safety margin so you can sneak up on the cut without wrecking things. I've seen guys skip the paper work and end up with a chatter mark that ruined a part worth more than the tool did. It takes five minutes but it buys you peace of mind and keeps the scrap bin from filling up.