This model is modified from the 1970's Meccano manual model 5.9 (construction crane with grab), shown in the illustration, below right. It has been modified to use only parts 1 to 50.
The main problems encountered were a lack of long bolts, plates, and parts for the grab. I am using parts outside of Meccano set 5 to do this. A major improvement is the larger base which stops the crane from falling over!
Long bolts in the base to the 3" pulley are replaced by double angle brackets and two normal bolts.
The original model had a very strange mechanism whereby as the crane was hoisting, it was also slewing. I separated out these two functions. Also note there is no mechanism to make the grab open and close. It took me a while to work out this was not a function of the original model either!
The grab is made completely out of strips, angle girders, obtuse angle brackets and normal angle brackets.
The flanged sector plates become angle girders at the edge and the inner ones are 4½" strips.
Set screws (69) and grub screws (69a) are used but these are assumed to be bundled as the gear or pulley part. Actually there is no reason why the set screws and grub screws cannot be replaced with standard bolts. A washer here and there may be needed to stop snagging against adjacent bolts.