Is there a clearance for the lower frame bracket that the steering column shaft passes through, just above where the pitman arm attaches? I know that is is to be lubricated and obviously the ones I have have not been. There is some shaft wear but no indication of any bushing through the bore of the support bracket.
Part #3545 (1909-1925) or #3545B (1926-1927) is the steering bracket bushing.
Have any idea what the clearance should be between the shaft and bearing?
All stearing shafts that were used very long are worn where they rub on the bushing. This leaves a KNOB on the end of the shaft where is sticks out below the bushing, You MUST put your shaft in you lathe and cut the KNOB down to the size of the worn area. If you don't when you size your bushing to fit the knob the bushing will be way to loose and you will have a bad shimmy. After I cut the knob down I just ream my bushing to a snug fit and go from there. By snug fit I mean your shaft will turn easy with no side movement.
I would shoot for .001/.002 clearance. (not "per side" but total clearance.)
Ditto what Dave and Jerry gave you. The steering bracket bushing is a commonly ignored source of play in the steering.