Custom Gear Rack Home » General Machining » Custom Gear Rack Product Summary The above picture shows an Thrust Bar Gear Rack. Click on above pictures for better quality. Specifications Materials: The material is 4140 plate that was flame cut and hardened to 280 Brinell. Size: 3 3/4" x 7 " x 59" long Gear Teeth: 30 teeth-4/5 DP. and flame hardened.