09-15-2016, 07:52 AM
Nice to see you making some chips Ed!
Darren is spot-on. The finish looks like it does because at that extremely light chip load per tooth you get built-up edge on the insert. The material builds up, shears off and redeposits on the workpiece surface. In extreme conditions it can build up and eventually shear off the whole edge of the insert!
Cold rolled 1018 steel is very prone to getting that finish. If you take a deeper cut (try to get deeper than the 1/32" corner radius of the insert when possible) and give it around 0.004" to 0.007" feed per tooth. Of course that's hard to nail down on a manual machine, but experience is what you get when you keep trying. For what I saw in the video, you were at about 1/2 to 1/4 the feed rate that cut should have been. Make the inserts work a little, they'll last longer.
BTW, you may not have a problem with spindle alignment at all. Keep in mind that it shouldn't necessarily look like a perfect cross-hatch pattern when using carbide insert tooling. Put a straightedge across the short dimension of the surface and check for light in the middle. Or, plop it on a surface plate and check with a dial test indicator. You shouldn't see any dip across the middle.
Darren is spot-on. The finish looks like it does because at that extremely light chip load per tooth you get built-up edge on the insert. The material builds up, shears off and redeposits on the workpiece surface. In extreme conditions it can build up and eventually shear off the whole edge of the insert!
Cold rolled 1018 steel is very prone to getting that finish. If you take a deeper cut (try to get deeper than the 1/32" corner radius of the insert when possible) and give it around 0.004" to 0.007" feed per tooth. Of course that's hard to nail down on a manual machine, but experience is what you get when you keep trying. For what I saw in the video, you were at about 1/2 to 1/4 the feed rate that cut should have been. Make the inserts work a little, they'll last longer.
BTW, you may not have a problem with spindle alignment at all. Keep in mind that it shouldn't necessarily look like a perfect cross-hatch pattern when using carbide insert tooling. Put a straightedge across the short dimension of the surface and check for light in the middle. Or, plop it on a surface plate and check with a dial test indicator. You shouldn't see any dip across the middle.