[TowerTalk] Old HWS671

[Art]

I'm about to pull a HWS671 vertical. There's a pad welded on the outer 
section. For those with an erection fixture it was used to install a 
pulley wheel to winch up the tower. I don't have a fixture, but I do 
have a tractor that I intend to pull it up with. The plan is to use 1/4 
inch 7x19, same stuff the tower uses, on a thimble around a bolt through 
the pad ordinarily used for a pulley with the erection fixture.

The question is, what grade of bolt do I buy that will pull it up and 
not break? I see it as a fight between ductility and brittleness, grade 
8 being brittle for shear loads like this. The hole is for a 5/16 -- 
which seems a bit small to yank up this tower. I'm sure it used to work 
when these towers were new 30-40 years ago. The alternatives are, drill 
out the hole for a bigger bolt or use a chain, either one putting the 
galvanizing at risk.

HWS671 is a 4 section 71 ft middling strong crankup weighing about 1400 lb.

73 Art