G-Code Lathe Project - The Seal Cap Part 8

Part Eight - Parting Off Safely

Parting off is the stage that finishes the first side of the Seal Cap, and it is also the stage where a healthy program most often turns into a broken blade. This lesson writes the cut for a 3mm wide part off blade, sitting slightly proud of the Ø10 bore, and talks through the decisions that keep it alive.

Setup habits come first: the blade rides dead on centre height, because just over centre rubs and just under centre grabs. Coolant gets aimed straight into the slot, since a deep cut traps swarf in the blade's own groove and a starved slot work hardens the metal until the blade stalls or snaps. Feed needs a considered value too, slow enough to never overload the blade, and steady enough not to rub and glaze the cut.

The program wraps the cut in breathing room. Spindle speed is capped before constant surface speed is stepped back in for the approach, clearance points sit far enough off the part to swing through without grazing the flange behind, and the cut itself is deliberately stopped short of the centre on this part so the blade is never left dragging on unsupported material. The final sliver drops with the part taken in hand, which costs a second and preserves the tool. Extra clearance before and after every cut costs nothing and gives you somewhere to catch a mistake before it costs a program.

Download the full G-Code handout for this lesson, along with the complete Seal Cap program, here

This free lesson series follows the Seal Cap build from first sketch to finished part and is a taster of what you will learn in the 4-Course G-Code Bundle.