Milling Hardened Steel

[oldmachinegary]

I recently bought a shaft and bearing assembly for a collectible car that I'm working on. It was too long for for my application so I decided to cut it to length on a Bridgeport. The bearing assembly prevented me from cutting it off on my lathe.
My question is if cobalt end mills are suitable for cutting what I think is a case hardened shaft (I ruined the HSS end mill finding this out). They seem to offer a significant cost advantage over solid carbide but I haven't been able to find out if they will work on hardened steel.
I ended up using an M.A. FORD Tuff Cut 7 end mill (I assume this is carbide) and it cut fine but I'd like to know more about the cobalt for any future purchases.
Thanks very much!
Oldmachinegary

 

[Cobra]

Depends on the steel you're trying to cut but Cobalt steel tools are just a subset of HSS. They have a greater resistance to softening at high temperatures.
If you want a good description, the Machinery handbook has a section on tool steels.

 

[joshua43214]

Enco has carbide mills in sale.
http://www.use-enco.com/CGI/INPDFF?PMKANO=397&PMPAGE=33&PARTPG=INLMPI&PMITEM=328-0019&PMCTLG=01