No. 9 aerial base

[Perry Kitson]

It seems there are 2 types of No. 9 base that were produced. The only difference being the diameter of tube that was used for the "stem" and the position of the weld, on top of the plate or the bottom. The two examples I have pictured on the left are made from schedule 80, 1 1/4" pipe, giving a diameter of 1.670". The other 2 examples (the two on the right in the right hand photo) are made from 1 3/4" tubing, giving (obviously) an outside dia. of 1.750". There must have been 2 different cages made to suit the two different diameter stems. I have tried a cage on the smaller dia. bases, and it will not tighten on. So it must be for the larger style base. Any input on which base is more prevalent? I am about to finish a run of repo's, and would like to make the more "popular" base, as I will be making cages as well.

thanks, Perry