Mcspeed

If the vendor doesn't take care of you, the two halves are probably held together with a rivet. Put the shears rivet on something very hard and flat( the anvil on a vise would be perfect) and tap the top of the rivet to peen it a little tighter. Go a little at a time until it is nice and smooth but tight.

Sometimes with wear, anyones tools can loosen some, this is how you can tighten them up.