How stable is Brass?

[Mic6]

I have a .75thk, 4.5 in square of brass, i have to hog a small pyramid shaped boss into it.(boss is .75 tall) The 1.5 flange around the center boss is .062 thick. Then I have to flip it over and mill out the inside of the boss to a .054 wall thickness. Not sure of the material grade. Think I'll have to do a bunch of flip-floppin'? or have warpage issues? TIA

[Robert Ouellette]

you are going to need to flip that a couple of times. i would rough the flange thickness and outside of pyramid. keep it cool. use coolant on it. flip rough bottom of flange and maybe some inside pyramid. then flip and finish top. flip finish bottom. leaving yourself .010 - .020" a side for finish. hardest part will be holding a 4 1/2" square 1/16" thick. cant hold it in vise it will bend. i would use the low temp wax on a nice flat 1" piece of alum. the one i use comes in a sheet like wax paper. lay it down on your tooling plate. put part on it. heat in oven to temp. remove from oven and let cool. hope this helps. let us know how it went.

[jeff]

That is not going to be fun.

I've never used wax before, just some really strong 2-sided tape for thin materials.... with varying success.

[Mic6]

It's gonna be a great way to start a Monday...

[Mr. Wizzard]

I would say it's fairly stable. I've had a piece on the floor by my desk and it hasn't moved in months

[BernieT]

Probably should stress relieve it 1st and maybe again before final cut.

 

Approx 550 deg F. for an hour or 2 should stop most of the warping.

[Mic6]

Forgot to update. I couldn't face the stock since it was already at thickness (which I HATE) I roughed the pyramid shaped boss/flange and left .05 on all surfaces. Placed it into a fixture to accomodate the boss, rough/finished the interior of the boss to size, drilled the required holes. Flipped it back onto a vacuum plate with pins to hold it laterally, finished to size and came out with no bow or warpage. I was quite happy! Thanks for all the suggestions/responses.