[JooJoo]

Originally Posted by HuFlungDung Yes, you are missing the better cutting capability of carbide. There is a critical speed to cutting steel that influences whether the chip tears out of the surface or comes off smooth. Look at chips produced by a regular HSS twist drill. Both sides of the chip are fairly rough. A carbide tool running at a suitable surface speed produces a chip with a smooth side. Carbide cutoff inserts can have a chip former groove on top with a 'drop center' which rolls the sides of the chip inwards, making the chip narrower than the groove which is being cut. This greatly assists in getting the chip to come easily out of the groove with minimal jamming. Often with good cutting parameters (correct feed and speed) the smooth sided chip will easily roll up into a clock spring, rather than producing a tangled mess of chips which are prone to wrap around everything nearby. The action of parting off with carbide requires a quite positive feed. This can be learned on manual machines, although it may seem unnatural and reckless to feed the tool in like a man , that is the way they work best. Coolant is highly recommended to cool the chip, lubricate it for easy removal and reduce the temperature at the cutting zone. Once you see a carbide insert properly applied, you may be tempted to toss your HSS blades and holders in the garbage. But don't HSS with a simple flat top (neutral rake) does a fine job in brass, bronze and cast iron.

I agree mostly, tool clearances, rake, chip breaker,nose rad., speed, feed, for the size of the material,blah, blah, whats important once thats sorted is having your part off square to the job and on centre and your slide can handle it cause if your gibs are loose you'll struggle buddy.
ps. Hang on to your HSS it's good for nylon as for non ferrous stuff carbide sharpen correctly for the application is chalk and umm anyhow HuFlungDungs on the money