Re: 16 finish on 316 .187 4" square plate

clay wrote:
John,

316 does not take to well with shallow cuts, for high finishes.
Normally you will need to take a deeper cut. At least .003" with
carbide, maybe more. You might have better success with HSS or cobalt
tools.
Did you know that you can buy SS plate pre-polished? I am not sure 316
*** is available that way, but is certainly worth looking at.

ca

Great help. Thank you.

I will try a cut of at least .005 and put down that carbide. Things are
never easy these days as the material was supplied by the customer and I am
contracting in a small shop so I have little control over the finer details.
From what I am told this whole operation is some kind of a rest of finish
results only. This is why the size and flatness is not critical. I guess
there has been little dealings with this plan in the past so I have to go
with the flow and see what turns out. The major difficulties I expect to
have is the feed and RPM which I will be trying to determine by using
CutData application or trial and error. So far error is winning by a
landslide.

John





John wrote:
BottleBob wrote:

John wrote:

I am about to try to get a 16 finish for electroplate on 316 sst.
3/16 thick plate. So far I have machined 1" x 6" strip to be cut
into 1" squares where I used a fly cutter which I sanded and buffed
that worked ok. The larger plate I am sure will be difficult so I
am asking for some pointers please.


John:

The easiest thing to do is what Charlie said. Have it double disk
ground and then lapped. But if you MUST do it inhouse some things
you might try are surface grinding it (blocking it and flipping it
repeatedly to try to achieve flatness). You could try using some
double back tape to hold it down while machining (holding it in a
vise will tend to bow a 4" piece that is only 3/16" thick). You
could clamp it to the table and machine half of it then move the
clamps and machine the other half. Sometimes a large flycutter will
impart enough heat into the part to bow it, one way around that is
to use a smaller cutter with multiple passes.
Anyway, those are just a few options to try.


Thanks guys.

I should have gotten back sooner. I only need one side to have the
finish. The other side will remain uncut. Flatness and thickness is
not a concert either. The problem I have is the flycutting. I cut 4
pieces that were 2 " square and that took several tries at about a
few thousands each pass. I hone a single point carbide(of coarse)
bit w/.030 R and try various RPMs and feed with as small a cut as
possible. Just enough to clean it up. I try oil and tried Kool Mist.
The first piece went fine then everything went down hill from there.
I now have far less fingernails then I started out with from
lapping. They have not bowed what-so-ever and only get hot when I
use a Scotch Bright wheel for buffing. They look nice but I am
feared when the electrofinsh is applied I will see what is not
visible as of yet. All the fine lines and scratches will most likely
shine like a babies ass.


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