Fred, when tightening the securing nut, did it in fact tighten because the nut was bottoming out on the steering column or because it ran out of threads?
The steering wheel telescoping lock works just like a bike fork works. If you ever took a bike fork apart you will see two tapered slugs. When the bolt is tightened the tapered slugs try and spread out, acting like a clamp inside tube.
Sometimes in the Alpine/Tiger columns these wedged slugs stick. Usually tight so that the wheel can not bee moved in/out.
In your case I suspect one of two things. Your treaded rod is actually not being pulled out far enough because you have some missing parts or the tapered slugs are stuck together. The latter is not likely.
What’s the fix.
1. Make sure the locknut is in fact bottoming out on the steering column. Use washers if necessary.
2. If stuck, install locknut on threaded rod and give it a couple very sharp blows from a hammer. You won’t break anything…..or shouldn’t unless yo use a 50 pound sledge hammer.
In my own Tiger, to make an aftermarket wheel work and still allow adjustability, I had to cut the threaded shaft off about an inch then use my own nut and washer.