AeroncaChamp
Cast Iron
- Joined
- Mar 2, 2007
- Location
- Westford, Massachusetts
Noobie question - how bad are blue chips?
I'm struggling up the learning curve, slowly. After initially having trouble with brazed carbide tools when I was first starting out, I gave up and worked with HSS for a while. I'm giving the carbide tools another go. Two recent jobs - one involved facing (fly cutting) a small rectangular block; the other turning a new gib locking screw; both cases I used a brazed carbide tool. I doubled the SFMs as I've read here and other places. Got a nice finish in both cases (hooray).
Depth of cut was varied 0.035" - 0.050" for the fly cutting operation, 0.015" - 0.045" for the turned screw body. Fly cutting was hand fed (no power drives on the mill); screw body feed was I think 0.003" per rev. Both SFMs and DoCs were greater than I've used for HSS tools and I crept up to the higher DoCs.
In both cases, I got dark blue chips - most of them in the facing operation, some in the turning operation on heavier DoCs.
Question is: how bad are blue chips for tooling and/or machine? Is this a sign of too rapid material removal or normal/ok for carbide tooling? If bad, am I at too high a SFM or too big a DoC?
Materials were "plain old" CRS stock (1018 or who knows what?)
I'm struggling up the learning curve, slowly. After initially having trouble with brazed carbide tools when I was first starting out, I gave up and worked with HSS for a while. I'm giving the carbide tools another go. Two recent jobs - one involved facing (fly cutting) a small rectangular block; the other turning a new gib locking screw; both cases I used a brazed carbide tool. I doubled the SFMs as I've read here and other places. Got a nice finish in both cases (hooray).
Depth of cut was varied 0.035" - 0.050" for the fly cutting operation, 0.015" - 0.045" for the turned screw body. Fly cutting was hand fed (no power drives on the mill); screw body feed was I think 0.003" per rev. Both SFMs and DoCs were greater than I've used for HSS tools and I crept up to the higher DoCs.
In both cases, I got dark blue chips - most of them in the facing operation, some in the turning operation on heavier DoCs.
Question is: how bad are blue chips for tooling and/or machine? Is this a sign of too rapid material removal or normal/ok for carbide tooling? If bad, am I at too high a SFM or too big a DoC?
Materials were "plain old" CRS stock (1018 or who knows what?)