I think another important question would be what RPM are you trying to cut the stainless with? If you are using high RPMs it will probably work harden the stainless even with a ramp. RPMs too high, inconsistent feed pressure and inconsistent application of cutting fluid can all be factors. Normally at lower RPMs a HSS bit can work well on stainless but at higher RPMs the carbide tools might be better. As was pointed out in the previous post, stainless will work harden very quickly if it is allowed to heat up significantly. You did not mention what number stainless you are working with and sometimes you can get better results using a different type of stainless when possible. If you have a variable spindle motor you will probably have better results using low RPMs, and if you don't you may want to see about getting another spindle for working with stainless.