Milling through chrome?

[KC2IXE]

I've got a smallish problem - or maybe not. I may have an ongoing project (OK product/service) where I need to retrofit a product. It requires milling a pocket in a mild steel base. Now, this product comes with either a painted base (which is what I have - and it worked fine) or a chromed base (aka it's a cosmetic chrome, not 'hard chome')

Any hints on milling through the chrome to get to the mild steel layer?

Charlie

 

[cmacclel]

I've turned Chrome parts and it was no problem. Plunging into it may be a little more difficult I guess.

Mac

 

[Dan FO]

Should not be a problem if the cutter is sharp, I used to use carbide cutters but that shouldn't be necessary.

 

[65535]

Once you get under it the chrome layer will flake off, it's the initial plunge that's the hard part. You could always sand it off first.

 

[precisionworks]

Chrome, either flash or hard chrome, is 68-70 Rc. You end mill will last longer if you can grind it away with a small stone in a dremel.

 

[KC2IXE]

Yeah, I know it's hard, which is why I asked

Here is the issue - I've thought of a product/service, which will basically have me milling a pocket about .4 deep, 5/8 wide, 3/4" long with a 1/2 or 3/8 end mill (corner radius NOT critical), dims are fairly loose tolerance except I can go "too deep" (basically stock varies somewhat in thickness, so long as I leave 1/16 or more stock I'm OK), and one wall of the pocket has a fairly tight dim to the edge of the stock

The thing is, it's a fairly "low budget" job. My latest though is to blow through the chome with a drill bit, change to an end mill, hog out the pocket (saving life on the end mill), and going from there. The question in this is how many clients are going to send chromed bases, vs painted

I'm beginning to think the best way MIGHT be (probably) to invest in a BATCH of carbide "re-sharp" end mills, and NOT worry too much - when they get dull, move on to the next end mill (might if I'm lucky, be doing 2-3/week) - when I'm down to the last 1-2, send the rest of the batch back out for resharpening again

 

[KC2IXE]

A follow up - I emailed SGS and OSG and asked "how would YOU do it" (Hey, they have applications support engs for a reason, right?)

The answer from SGS is to use their Z-carb end mills, but to get a carbide drill, and drill out as much of the job as I can first, then mill the rest, and expect the end mill to wear badly at the depth of the chrome - maximize life by doing variable depth passes to the edge - then go down to the bottom

Makes sense