Ran my first batch of 4140 at 180 SFM instead of 250 and the inserts lasted 3 times longer

Robin Sanchez · 2026-10-16T21:40:04.543299+00:00

Last Tuesday I had a rush job on some 4140 pre hard and my tool rep swore I needed to push it at 250 SFM to hit cycle time, but I went with 180 instead because I was tired of burning through inserts every 40 minutes. Ended up finishing the whole run of 60 parts on one corner of a CNMG and still held plus or minus .0005. Any of you run pre hard that slow or am I leaving money on the table?

🐿️Pinecone Attack

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Ran my first batch of 4140 at 180 SFM instead of 250 and the inserts lasted 3 times longer | CNC Operators - Pinecone Attack