Facing Cast Iron

[tom_d]

You would NEVER face the entire back.

I assume the idea is to assure that the surface ON A THREADED SPINDLE FACEPLATE which hits the "shoulder" is intended, and that in order to assure that the surface will repeatably mount the same exact way.

Obviously it would not apply at all to those "bloated plutocrats" who have L and D series mounting systems

Just a guess, but it might be that the idea of taking a chip on both sides of the plate originated in the practice of skimming both sides of a plate to remove stress at the surface like we find when machining an aluminum plate.

[BCRider]

Prior to buying my 12x36 import I'd only seen plates without as cast features on the back on a couple of very small lathes where the plates were likely machined from solid... Or to use the overworked term "billet"...

But then this came with my lathe....



So "they are out there"....

I'm not sure I'd bother with the whole back. But given that this doesn't get used often I'd lightly stone or otherwise clean up the flat register to remove the marks seen here.

I've only used the face plate twice that I can recall over the 25'ish years of ownership. The first time around I checked the runout. It was fine so I've never bothered since. Most of my offset needs are handled by the 4 jaw.

[kf2qd]

For a HHS tool I never grind any relief in the top, it just makes it harder to grind the next time around. I use my HSS flat on top and adjust for positive or negative in the holder. Ir use Cabide. For brazed tooling the same rules apply. I have had many tool bits come my way that have had various top reliefs ground into them and all it dis was cause them to fail faster. Keep your grind simple and with a little side clearance where needed and it will work just fine.

Chuck Adapter Plate - Where does it really contact the chuck. Make sure that area is as true as you can reasonably make it. And put a sligh undercut on the rest of the face so it does seeat properly.

Don't overthink things and make it more complex than it needs to be. There are many who take things to extremes and do no better than the one who does a proper job and gets to real work..And there are ones who take it to extremes and never get anything done. Don't be them.