You've also got to watch the profile of these inserts. If you try to use different manufacturers inserts in your APKT cutters. Each manufacturer can use different helix angles for their cutters, leaving you mismatch when machining 90 degree walls when you use persay an Ingersoll insert in a Iscar cutter. I really noticed this when trying Seco inserts in Iscar cutters, and the reverse. This was only a last resort, as we had none of the right inserts left. Do what yah gotta do! Right.
You must also be aware of the recommended machining parameters when switch suppliers, as the Surface speed and Feed requirements may change as well. It's not simply a staright switch.
Even if you stayed with Iscar, and just switched the grade, you would have to pay close attention to the machining parameters. I`ve used IC328`s on stainless with god sucess. For steels, I used to have great sucess with the IC950 grade, provided you machined dry. This grade is really suceptable(sp) to thermal cracking, so unless you can totally, and I mean pretty much machine in a aquarium, immerse the cutting zone in coolant, it`s better to use none at all. Just pay attention to your chips. They`ll tell you if you`ve got it right.