[TightFit John]

We have little experience with stainless steel. Customer has requested an order of parts usually machined from aluminum to be made from 303 SS. We will need to profile 1"X5" and 1.5"X3" bar stock and mill, drill & tap and turn the parts. Recommendations for proven drills, taps, inserts, etc. would be appreciated as well as general tips for working with 303 stainless.

[TR MFG]

Hanita Varimill endmills work very well.

[ctate2000]

You are going to have a difficult time finding 303 SS in those sizes. 304 is most common in flats. It is hard to suggest tools with out first seeing the part. You may want to consider having the blanks cut on water jet first and then finishing the profile. You can cut 304 very fast when removing small amounts of material. There is a drill from OSG call the Exgold which is fantastic in SS.They cannot be beat. They are priced accordingly of course. Any mill needs to be very sharp and the feed needs to be aggressive. Supply plenty of water soluable coolant and flush chips away from the cut. When the tool shows the first signs of being dull change it immeadiately. Dull tools in SS cause bad days. Chips from SS should always be shiney and sliver any color at all is and indication that catastrophic falure is soon to come. Be careful pricing this job. SS loves to consume tools. OSG makes a great line of tools for the machining of SS. Call them for a recomendation.

[OkumaCaptain]

ive probably machined about 10 miles of SS bar stock varying diameters. Iscar makes some awesome tooling for machining it, i reduced a 12 minute cycle to 4 just with their tooling. having parts roughed waterjet is a good idea, but if you have nice machines i would not worry with that.

[Caprirs]

Keep the coolant rich also, especially for the tapping. Cobalt drills last well compared to HSS and are cheaper once you start breaking HSS and replacing.

[NC Cams]

We had a situation once where we had to make a fixture out of stainless (don't recall the grade anymore).

We contacted the tech services dept of the steel mill that made the billet. THey suggested speeds and feeds and coolants.

Result: the "sage wisdom" method of our shop supervisor burned up a small fortune of carbide, HSS and god knows whatever else he tried in the way of tooling.

He then tried the "..that'll never work..." specs provided by the mill's tech dept and it cut like butter. WE learned that you have to CUT the stuff and get the chips out of the way or else it work hardens and then you'll do nothing but burn up tooling.

Check out the machining section of the following book:

Engineering Properies of Steel by American Society for Metals.
ISBN 0-87170-144-3

Page 265 thru 271 gives all kinds of speeds, feeds and tool suggestions for cutting, drilling, tapping and grinding 303SS. They list specs for HSS, M1, M2, M7 and uncoated C-2 carbide and coated CC-2 carbide.

My copy is dated 1982 but an up-to-date version would surely be on file at a local college engineering library. You can also buy a copy from ASM - they have a website.

I also think they have a book specifically outlining the machining of stainless materials.