steering stack

[Cycle-psycho]

I am trying to get my steering stack set up and I am getting conflicting information. On the top side of the stem, there should be:
-bearing
-dustcover
-star nut
-tab washer
-jam nut
-tree
-top nut
Now what confuses me is that sometimes i see that the jam nut is omitted and the tree and top nut seem to take its place. Is this acceptable? I am having clearance issues with my hardware as the star nut i have is about 3/8" thick, then add the tab washer and a jam nut, and there is about 3/4" of stuff to try to bury into the tree in order to hide it. my tree is 3/4" thick, so I cant hide it all. I guess i could cut another 3/4" piece to weld to the underside of the tree that will hide the stack.
How thin can I make the tree in the stack area before it gets dangerous? is the connection of the tree to the stack/stem the main securement point, or is the connection of the tree to the main legs the main securement point? Or all three points (stem and two leg ends)?
Thanks for any help....

[gww25]

This is hard to explain but bear with me. First of all your top tree should have a 1.25-inch hole where the 1-inch steering stem penetrates, That hole allows the bosses on the various nuts a seat to sit into. The top tree however should never actually put any weight weight on the upper stem bearing. The tree actually bears on the fork leg studs. The star nut puts the bearing under load and you need to be able to put one of the little special 1/8" thick spanners on this nut when the tree is in the installed position so in reality that nut is never hidden, except for the boss or collar which will be up inside the tree. The top tree is intended to steer the forks by bearing on the fork leg studs and it should not be putting any force or weight on the stem or the various nuts installed on that stem. Look again at the pictures I posted in your other thread. Also go take a look up under the top tree on some stock bikes and look at some of the exploded part views in the shop manuals. If you really want a clean look you can buy a jam nut that's very thin without a shoulder and the lock washers aren't really that necessary if you use some blue loctite.

[Cycle-psycho]

Thanks Gary, that helps a lot to understanding the principle here. There must be some lateral stability accomplished by the top tree having the stem going through it or the front end would collapse, but its not any form of compresive support on the bearing. Therefore, the top tree does not have to be as thick in the stem area as the lower one. This will allow me to make some of the star nut hide inside the tree ( and as you say, leaving enough room for the nut adjustment.
I think im getting closer to understanding the logic here, it helps to build when you understand the principles.