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.
TIA John
What kind of flatness tolerance do you have to hold? If it's not important you can sand it smooth, but if flatness is an issue you may best solve the problem by sending it out to a shop that does lapping. Are you buried in work? Send it out. Only job in the shop? Fly cut and sand.
Later,
Charlie
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.
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 sheet is available that way, but is certainly worth looking at.
ca
John wrote:
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
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