Found out my old boss's template speeds were from a 1995 book

Was cleaning out the shop office last weekend and found a beat-up copy of CNC Programming Basics from 1995. Flipped through it and realized the feed and speed numbers my old boss swore by came straight from that book, word for word. We ran those numbers for years on our Haas machines in Austin, and honestly they were fine, but modern tooling has way better data. It got me thinking about how many of us still use habits from decades ago without questioning them. Anyone else ever trace a setup trick back to some random old source? How do you know when to update your go-to numbers?

2 comments

2 Comments

casey1621d ago

Man, that 95 book probably had a 3/8" end mill at like 1500 rpm and 12 ipm in mild steel, right? Those numbers work, sure, but they're not even close to what a modern coated carbide can do now. I caught myself doing the same thing last year, turned out my whole default set was from a 2003 shop manual. What I do now is run the numbers through my tooling supplier's online calc first, then check them against whats actually in the machine, just to see the difference. Honestly, just start with one tool you use all the time and update that, the rest will follow when you see the cycle time drop.

joelwells20d agoMost Upvoted

The last time I trusted a 1995 speeds and feeds chart, I snapped a 1/2" end mill clean off and spent forty minutes digging the pieces out of a part worth twice what the tool cost. That was my wake up call too, @casey16, except my "modern update" was switching from the 95 book to a 2003 one, so I basically traded one dinosaur for a slightly younger dinosaur. I finally ran a test with some coated carbide and the cycle time on a simple pocket dropped by damn near half, which made me feel like an idiot for all those years of babying the feeds. Now I just use the supplier's calculator for the rough numbers and then fudge them down about ten percent because I don't trust my machine's rigidity or my own nerve. The funny part is I still keep that old book on the shelf, mostly as a reminder that my default setting is always going to be "too careful.