Candidate 3: Deepfire Titanium Piston (full)

Relative newcomer Deepfire produces an interesting and unique piston, using a full rack of metal teeth mated to a nylon piston body. The motivation behind this design is clearly to minimize piston weight while retaining the durability of the metal teeth. Additionally, a plastic piston body can better absorb the impact forces of a high powered spring, helping to reduce the beating a mechbox takes under these conditions. The rack of metal teeth is mated to the piston through a slip fit into grooves on the piston body. The fit is relatively tight and requires some force to displace. The rack is retained on the piston in the standard manner using a 90 degree tab at the end of the rack which catches the piston face. The metal teeth are coated with titanium nitride giving them a silvery shine. Titanium nitride is a well known surface coating commonly used to increase surface hardness and lubricity which should benefit the durability and friction characteristics of the piston teeth.

Piston: Deepfire Titanium Piston (full) Weight: 0.7oz Piston Material: nylon Metal Teeth: all Average Barcol Hardness (piston): ~3* Average Barcol Hardness (main teeth): 85.1 Tapered Lip: yes Distinguishing Feature: full rack of TiN coated teeth on nylon body *Note: the Barcol Impressor registered a starting hardness of ~3, but progressed to a zero reading shortly thereafter

The grooves and removable teeth rack are illustrated in these photos.