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Ran 4140 pre-hard or annealed on a 3 inch shaft job, went with pre-hard and it cost me
Had a job come through my VF-2 about 6 weeks ago. Shafts for some ag equipment, 3 inch diameter, 14 inches long, needed a keyway and some turning down to 2.5 on one end. Customer said 4140, but did not say which condition. I stood at the bench and went back and forth on it. Pre-hard is nice because it holds size and you skip heat treat. But it eats inserts and my machine is not the beefiest. I went pre-hard anyway because I was behind on a rush and did not want to wait on an outside heat treater. Big mistake on my part. Burned through 6 CNMG inserts on the first two parts and had to slow the RPM way down to keep the chatter out. The annealed stuff would have cut like butter and then I could have sent it out for hardening. Ended up eating about $140 in inserts and a whole afternoon. Customer did not care either way, he just wanted the parts. Anyone else get stuck picking material condition when the print does not spell it out?
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barbarac6726d ago
Man that is a rough one and I feel for you. Been there with the whole "which condition is it" mess when the print just says 4140 and nothing else. Pre-hard on a VF-2 with a 3 inch shaft is asking a lot from that spindle, and burning 6 inserts on two parts sounds about right for that setup. The worst part is the customer didn't even care, so you ate the cost for nothing. Maybe next time the move is to just call the customer and make them pick, that way the insert bill lands on their side if they want pre-hard. Live and learn I guess, but that afternoon stings for sure.
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