June 2009 / Volume 61 / Issue 6|
Keeping your cool with salesmen
By Dr. Jeffrey Badger
Dear Doc: I grind bearing steel and am trying to increase feed rates without getting grinding burn. I got a new wheel salesman and he suggested a new—and rather pricey—wheel with “cool-cutting characteristics.” When pressed for more details he just repeated the term “cool cutting” over and over. What exactly does that mean? Does my wheel salesman know what he’s talking about?
The Doc Replies: I’d give 10-to-one odds that your wheel salesman’s previous job was selling toothpaste and, instead of saying he doesn’t know the details, is trying to bluff his way through.
There are definitely cool-cutting wheels, and there’s no shame in using that term. But your wheel salesman has to do a better job describing why it’s cool cutting.
A wheel can be cool cutting in many ways: It has high porosity and therefore can carry more coolant to the hot spot. It uses a friable grit instead of a tough grit, so the wheel self-sharpens better via grit fracture. It has a softer grade, so it self-sharpens better via bond fracture. It grinds with an angular instead of a blocky grit, so the grits attack more aggressively (which reduces rubbing) and fracture more easily (which improves the wheel’s self-sharpening ability).
I work with wheel salespeople all the time. Some are very well educated and experienced in grinding—and some are absolutely clueless. The following are some of the telltale clues of a clueless wheel salesman:
This last one drives me crazy, and I want to ask, “From where did you pull that number?” Assuming no adverse side-effects, a 250 percent increase in wheel life is impressive but achievable; a 250 percent increase in feed rate is nearly impossible without sacrificing somewhere else. Which one is he talking about?
The following is a conversation I recently had with a wheel salesman.
Salesman: “It’s a cool-cutting wheel.”
The Doc: “Why is it cool-cutting?”
Salesman: “Because it generates less heat.”
The Doc: “Why does the wheel generate less heat?”
Salesman: “Because it’s a cool-cutting wheel.”
Of course, if a salesman works at an industrial distributor selling everything from grinding wheels to air compressors to toilet cleaner, cut him some slack. But if he works for a grinding wheel company, he should know this stuff.
Here’s the final litmus test. Grinding is complex, and there are no guarantees. So when asking a wheel salesman if his wheel works better and he answers “absolutely,” you’ve got yourself a clueless wheel salesman. But if he says: “I’m not sure. Here’s what I know. Here’s what’s worked before and here’s why I think it’ll work for you, but I can’t be sure until we try it,” then he’s a keeper. CTEAbout the Author: Dr. Jeffrey Badger is an independent grinding consultant. His Web site is www.TheGrindingDoc.com.
CUTTING TOOL ENGINEERING Magazine is protected under U.S. and international copyright laws.Before reproducing anything from this Web site, call the Copyright Clearance Center Inc. at (978) 750-8400.|