I thought I would start a new thread for this, as it may be of general interest. It may be a well known common problem, but unknown to me.
This bike had a punctured front tyre when I bought it, so I had to remove the front wheel.
I found that there was an M6 dome nut on each end of the spindle. On removal, I found a through length of rough M6 "all-thread", with about four assorted washers under the dome nuts. Most strange!
I fitted an allen key in RHS and unscrewed the spindle, removed the wheel and took it for a new tyre. When I looked closely at the spindle, I found a crudely tapped thread in the LHS end.
I tried an M8 x 1.25mm screw, but it did not fit. I tried another with a 1.5mm pitch, also incorrect.
With thread gauges, I found it was 18 tpi, which my book suggested was 3/8" BSF! Why? I also noticed the RH end was heavily "belled out", obviously there had been some hammering on the end in the past. Again, Why?
In due course, I came to put the wheel back, but had a struggle to line it up in the LH end. After resorting to light taps with a wooden mallet, I started to get it to screw in, but when it was more or less fully up, it simply continued to turn. There was no thread left in the LHS fork leg!
My solution is as follows (but I invite critical comment.)
Attached is detail of the spindle and fork ends.
I put the spindle in the lathe and tidied up the belling of the RHS as a first step. I then CAREFULLY tapped the LHS with a 3/8" BSF tap, to a greater depth than before, with an overall improvement on what was there before. I have now to make a special thick washer with 3/8" clearance, and that 3/8" increased to 16.5mm. This will enable the spindle to be tightened up properly against the speedo drive on RHS.
Cheers, Les.
