Don't worry about. Looks like the frame is a road frame (126 - 130 mm spacing) and the hub is a 120 mm track hub. Just tighten it up the steel will spring the 3 - 5 mm either side. This will not effect your chainline. That is defined by the hub and then needs to be matched by the correct combination of crank and bottom bracket.
P.S The hub MAY be an 110 mm, a rare old spacing, just stick 5 mm of washers either side if it is to reduce the flex in the frame has to go through.
Don't worry about. Looks like the frame is a road frame (126 - 130 mm spacing) and the hub is a 120 mm track hub. Just tighten it up the steel will spring the 3 - 5 mm either side. This will not effect your chainline. That is defined by the hub and then needs to be matched by the correct combination of crank and bottom bracket.
P.S The hub MAY be an 110 mm, a rare old spacing, just stick 5 mm of washers either side if it is to reduce the flex in the frame has to go through.