# Is It Possible To To Use A Router Bit On 316 Stainless?



## JimDawson (Dec 13, 2015)

I am working on a project that requires some 2mm thick, 316 SS parts.  These are about 2.95 inch dia., with 10 6mm (0.239 inch) notches cut in them, like below.  I'm doing 6 at a time out of a 12x12 piece of 14ga SS, 14ga is close enough to 2mm for this project




First I anchored the MDF backer board to the table with a couple of flat head cap screws.  Then clamped down the SS and drilled & countersunk the screw holes.  Then screwed down the SS.

Then I roughed out the circles with a 3 1/4 inch hole saw, this gave me an OD of about 3.07 on my parts, plenty for clean up.  First time I've had my mill in back gear in a long time.  Ran the hole saw at about 30 RPM



So the answer is:   YES, it is possible to mill 316 SS with 3/16, single flute, carbide tipped router bit.  1800 rpm, 0.045 DOC, full cutter width on the notches, 2 IPM, with WD-40 as coolant

I was at the big box store picking up some 1/4 inch solid carbide 2 flute, spiral router bits for the aluminum parts of this project and saw that 3/16 straight flute carbide tipped on the rack.   So what the heck, I'll try that, less expensive than my end mills.  Seems to work fine.

I use carbide router bits in my mill all the time for aluminum, and of course in wood, for general cutting and corner rounding.  But have never tried one in SS.

It's running right now, so I'll let you know if the bit made it through all of the parts.  Since I have my coolant system running reliably, I'm comfortable walking away from the machine for a bit.


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## Ulma Doctor (Dec 13, 2015)

i wouldna thunk it!....


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## JimDawson (Dec 13, 2015)

OK, they'er done.  The tool still feels as sharp as brand new, and the parts are on size.  I couldn't measure the diameter of the bit because it's a single flute, so after the roughing pass I measured the part and found that the tool cuts 0.003 undersize.  No problem, I plugged in the tool size offset and life is good.  It's common to find endmills undersize, especially the carbides, so finding a router bit undersize is not surprising.  The edge burring is minimal, and a few minutes in the vibratory will completely clean them up.

That blob of metal between the disks, center, left is the socket head cap screw (grade 8) that was not counter sunk deep enough and was cut by both the hole saw and the cutter.  Both went through it like butter.  I normally countersink the cap screws deep enough they won't get hit by the cutter.  OOPS!


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## Cheeseking (Dec 14, 2015)

Very nice work sir.  At my work we process various 300 series stainless daily (cnc turrets, waterjet and soon a laser) and its definitely merciless stuff.   If you posted this before you attempted it I would have bet against success.


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## JimDawson (Dec 14, 2015)

Cheeseking said:


> If you posted this before you attempted it I would have bet against success.



Thank you for the kind words.

Me too


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## Ulma Doctor (Dec 14, 2015)

(in my best Kung Fu Master voice)

Greatness comes from outside of box...


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## ch2co (Dec 15, 2015)

I read the topic line of your post and immediately said NO WAY!  I've worked enough with stainless to know such things.  In the words from the Princess Bride
"Inconceivable!" 
 Thank you for proving everything I ever believed in was wrong. ;-)
But seriously folks (Joe Walsh) you have challenged and redirected the neuronal pathways in my brain and I thank you sir. 


CHuck the grumpy old guy


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## Andre (Dec 15, 2015)

You could measure the diameter of a single flute cutter. Put a 3/16" dowel pin in the collet, use an indicator and zero it out on the pin then switch to the router bit. Since it's single flute rotate it in the collet between every measurement, than average the readings.


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## JimDawson (Dec 15, 2015)

Andre said:


> You could measure the diameter of a single flute cutter. Put a 3/16" dowel pin in the collet, use an indicator and zero it out on the pin then switch to the router bit. Since it's single flute rotate it in the collet between every measurement, than average the readings.




You are correct, Andre!


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## kingmt01 (Dec 17, 2015)

Andre said:


> You could measure the diameter of a single flute cutter. Put a 3/16" dowel pin in the collet, use an indicator and zero it out on the pin then switch to the router bit. Since it's single flute rotate it in the collet between every measurement, than average the readings.


Thanks. I've been wondering what a good way to do this is actually in any cuter.


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