Chess Rook

» Video: Turning the Chess Rook

This single-part project demonstrates a variety of machining and programming techniques, and utilizes a number of the Mori Seiki NL lathe's features.

Material Selection
2.5" diameter 6061-T6 aluminum bar was used because it's easy to polish and anodize. It fits easily within the 3.1" bore of the spindle and Kitagawa 10" chuck. The chuck jaws were borrowed from a past project where they were shaped for tool clearance.

Turning and Facing
A VCGT insert was used for profiling, and a CNGP insert was used for facing. Cutting speed was limited to 450SFM when cutting dry to prevent chip welding, but could be cranked up to 850SFM with coolant.

Engraving
Engraving was accomplished with a TiN-coated 1/4" diameter drill-mill in an ER collet. The maximum live-tool speed of 6000 RPM was used.

Boring
The bore at the crown of the chess piece was roughed out using a combination of plunge and helical moves with a 3/8" 3-flute aluminum cutting endmill at 4500 RPM. Speed could be increased to 6000RPM with coolant. Cutting the slanted profile of the bore and finishing the bottom was done with a 3/8" carbide boring bar and a CPGT insert.

Slotting
The slots of the crown were cut using a 1/4" 3-flute endmill at 6000 RPM.

Bandsawing
A 4-tpi bandsaw blade quickly cut through the material, separating the chess piece from the rest of the bar. A bandsaw was used instead of a part-off blade simply for convenience in this case.

Back Facing
Steel chuck jaws were bored using a VNMG insert in an MVUNR boring bar, cutting a dovetail shape to grip the crown of the chesspiece. Back facing was accomplished with a CNGP insert to complete the machining portion of this project.

Finishing
1200-grit sandpaper attached to a Festool random orbit sander was used to quickly remove all burrs from the engraving and the crown. A vibratory tumbler with walnut shells and rouge polished the parts in batches of five to a high polish in eight hours. Optional orange anodizing was done on a portion of the parts.







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