The base raises the Jiffy unit 3 inches. The base is keyed on top and bottom for precision alignment. The base is also used to clear part fixtures and add clearance for oversize motors.
The J-448 break through retarder valve is used to reduce the pulling of the drill into the material. It creates a counter balance (low back pressure) on the front of the drill unit. The retarder valve pressure setting is adjustable. It is desired to keep this counter balanced pressure as low as possible and still prevent drills from being pulled into the material. The feed pressure must overcome the retarder valve pressure setting. Due to pressure intensification of the drill unit, the feed circuit pressure must be limited to 800 psi maximum. Connections are 1/4"-18 NPTF, 2 places.
This counter balance valve consists of a reverse flow 30 PSI check to retract the spindle and a pilot-operated, balanced-piston relief cartridge which is a normally closed pressure regulating valve to retard spindle advance. When the pressure at the inlet (port 1) reaches the valve setting, the valve starts to open to tank (port 2), throttling flow to regulate the pressure.
The J-449 inline flow control regulates the flow rate of the hydraulic fluid advancing the drill spindle. Based on the feed rate of the spindle these flow rates may vary from fractional GPM up to 2 GPM. A feed rate of 0.2 inches/second results in a flow requirement of less than 0.18 GPM. Though for a rapid retract you would want 2 GPM available to return the drill in under 0.6 seconds. Connections are 1/4"-18 NPTF, 2 places.
The J-450 rapid advance valve is used to quickly advance the spindle to the work piece, then slow down and advance at a much slower feed rate. When rapid advance valve is de-energized, it acts as a check valve, allowing flow from 1 to 2, while blocking flow from 2 to 1. When energized, the poppet lifts to open the 2 to 1 flow path. In this mode, bidirectional flow is allowed. Connections are SAE-04, 2 places. Solenoid voltage is 120/60.