Is It Possible To Face Mill Hardened 4140?

Another quick tip.... Fly cutter sounds fine. And the bigger the insert radius the better. To reduce chipping, take the widest cut possible because you will minimize entrance shock as well as exit shock. Zero load at entrance full load at centerline and zero load at exit. If your cut is smaller than the cutter diameter, use conventional milling to reduce shock at entrance. This is especially successful with ceramics. If you are able, use the biggest lead angle possible and place initial impact above the bottom tangent of the insert. Use .002 chip load on a small radius insert and up to .005 with a 2 or 3 rad. Depth of cut, do not use more than 30% of the corner radius. This will allow for some chip thinning. 225 SFM to 250 SFM will do nicely for carbide, run 1,000 SFM for a AL2O3TiC ceramic. NTK HC2, Kennametal KO90 are good for starters.

Good Luck!
Gary
 
Some really great replies fellas. I do appreciate it.

You know, when I thought about this originally, I was not thinking about how I'm going to hold it to the table.

Now that I think about it, I have no idea how I'm going to hold it on the table, lol.

So, just to explain a bit further. I bought this piece of steel and had it heat treated about as hard as they could get it so that I could use it as an anvil (I forge knives). Over time, it has acquired quite a few dings. I am wanting to just resurface the top in order to remove the dings that have accumulated. It is 5" square bar that is 12" long (tall). I'm actually not even sure I'll have enough room to fit it under the spindle of the mill - maybe I should go check that.

Ideas?

(don't mind the cup ring, it will get burnt off in short order :)
anvil.jpg
 
Here's how I hold stuff that is too tall. This is a BIG stepper motor (about the same size as your chunk of steel) that I had to drill the shaft on. It is clamped to an angle plate that is bolted to the table.

IMG_0007.jpg
 
OK then, I would get a 4 ½” right angle grinder fitted with a shallow grinding cup wheel. Then jig up the grinder to swing and arc over the top of that anvil. Move the anvil and or grinder to do all of the top. Or some similar idea with a grinding stone fitted to a router. And the router being guided by a reference surface above the anvil..Good Luck, Dave.
 
Jim: I really like your work holding idea above. I know I will be able to use that some time.

Thanks, Gary
 
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