Best strategy for milling top of large steel piece

[rronald]

I could use a lathe. A bit scary to have that much weight turning round. But, it ought to fit into the 4-jaw chuck and I can see that it would have some advantages:

1. It would still be an interrupted cut, but the cutter engagement would occur in a better pattern (I think).
2. I imagine I could get a micrometer on the bottom of the part. My mod vises for the mill hold the part 19 mm above the fixture plate...which is enough to get one end of a 1" micrometer underneath, but not a 2"-3" (or the metric equivalent. Although I could make some spacer blocks to elevate the mod vise pieces for mike access.
3. It might be easier to indicate the part into the lathe chuck to make sure it's flat.

Next time I have something big and flat to cut like this, I'll give it a try.

To finish this piece, I think I'll try my 1-1/4" insert mill. FS Wizard says I ought to be able to take about 1.5mm DOC at full width and ~1600 RPM. With almost a m/min feed rate. I'll start with about 1/2 that DOC.

 

[Parlo]

Set the diameter of the flycutter to just over the part width. This will give tangential tip engagement with the workpiece.
Greatly reducing:
Tip impact
The interrupted cut forces on the spindle bearings
Increasing:
Cutter RPM + feedrate, leading to a faster metal removal rate.
Better surface finish & flatter faces.

 

[rronald]

The 1-1/4" insert mill worked well. Much more pleasant than the fly cutter.

However, I need to build something to contain the chips! They are a nice blue color, but essentially carpet the floor where they wait to attack the soles of my shoes.

 

[RaisedByWolves]

The 1-1/4" insert mill worked well. Much more pleasant than the fly cutter.

However, I need to build something to contain the chips! They are a nice blue color, but essentially carpet the floor where they wait to attack the soles of my shoes.

Not a big fan of them per se, but they make segmented poly shields for this sort of chip containment.