Gate Latches, or Hook and Eye latches
I have also seen these described as 'cabinet latches' they are commonly used to hold doors and gates in the open or closed position, but they can be used to link parts of bee hives together, mainly made from zinc plated wire, but some are sheet metal. They are readily available from hardware stores in the form shown in the drawing at right. Which shows a screw eye linked to the latch and the free screw eye that acts as a receptacle for the hook.
For use with bee hives the screw eye that is linked through the latch loop is removed, if the eye is twisted sideways and unlinked it can be twisted back into shape and still remain a usable screw eye for other purposes.
The robust looking one illustrated at right, is in fact only 50 mm long overall, made from 2.3 mm wire. The inside diameter of the pivot ring is 5.5 mm. I have used this size to couple pairs of 5 frame nuc boxes side by side so that they fit on standard sized floors and can have a full sized roof placed over the the top of the pair.
The large rough looking one below was retrieved from a hive stand that had been in service for approximately 15 years. Corrosion is evident, but is not that bad. Dimensions are 75 mm long, 3 mm wire diameter and again the inside diameter of the pivot ring is 5.5 mm. I no longer use this method of retaining the hive in position on the stand.
There is a 100 mm long version, that is of similar appearance, but I have only used them in the same way as the 75 mm ones.
All the wire types shown above have used wood screws as the pivot, on some occasions I have also used non ferrous washers, fibre washers or nylon washers between the latch and the wood that it is fixed to. As with all other metal components, that I use with bees they have been wiped over with a cloth impregnated with petroleum jelly.
There is a small latch that is made from sheet metal, either brass or plated steel. The drawing at right is executed to exactly the same scale as the 50 mm and 75 mm wire types (for comparison). These have proved useful in various special frames. The pivot hole is 3 mm and the pitch between pivot and latching screw is 21 mm, material thickness is 1 mm.