e bronze "oilite" bearings arrived today so I completed the construction of the aileron and flap torque tubes. The bearings as purchased were 30mm OD and 15mm ID. They were drilled out to 18.5mm and then reamed to be a smooth fit on the 3/4" aileron torque tube. Oilite is very strange stuff! As the metal gets hot, oil bubbles out of the porous metal and as you drill it the swarf is like a dirty brown paste but they are self lubricating and they certainly provide a good bearing surface. The end of the flap torque tube was then heated to expand it and the bearing tapped into position (note for future reference - it's also an idea to put bearings in the freezer to 
make them contract before fitting). The bronze bearings are at the inboard end with Delrin bearings at the centre and outboard end of the flap torque tube.An additional bearing was reamed to be a tight fit on the aileron torque tube. This was then cut in half and a piece inserted about 2" into the inboard end of each aileron spar. The aileron torque tube was then inserted into this and the washers made previously inserted at the end. The piece of bearing acted to exactly centralise the aileron torque tube in the spar and by inserting the aileron tube into the flap tube and lining up the two tubes the washer could be tacked in place with everything perfectly lined up. The aileron torque tube was then removed for final welding to avoid damaging the Delrin bearings. I might drill and pin the two tubes together through the piece of oilite bearing as a belts-and-braces measure but haven't decided yet.
