Jackscrew, part of the Apollo Crewman Toolset.
Used for restraining the side hatch in the event that the latch mechanism would not engage due to deformity of the hatch.
When engaged in a fitting on the hatch frame and on the hatch, the wingnut would be turned clockwise to draw the hatch into the frame.
Three jackscrews were provided in the Crewman Toolset.
0.66 lbs. (.30 kg)
Historic Space Systems at www.space1.com