Where can I get a new steer tube or 1 1/8" 6061 Aluminum Rod Stock? I have an Anti-Gravity fork that features a removable steer tube, but it is a threaded fork. Where can I buy a threadless steer tube to clamp into it to convert it? All I can find are threaded steer tubes or steer tubes pressed into a specific crown.

Here's a picture of the fork: http://www.retrobike.co.uk/forum/files/antigravity_fork_728.jpg . When viewed from the rear, by loosening two bolts I can remove the steer tube (it's already 1 1/8"). Do most forks not do this? Why aren't these more common?

This seems like it would work just fine: http://www.onlinemetals.com/merchant.cfm?pid=6997&amp;step=4&amp;showunits=inches&amp;id=71&amp;top_cat=60 , 1.125" OD, with 0.065" walls for a 0.995" ID would that be close enough to put the threadless cap inside?

Essentially, I'm looking for two things:

1) Where can I get the 1" ID 6061-T6 Aluminum, and

2) Why can't I find this by searching for 'threadless steerer tube'?



Here's a picture of my fork specifically.
2 things: 

While many older forks used replaceable steerer tubes, the steerer tube is still specifically  shaped for that fork. Tubing will not do it. You need an oem replacement steerer tube. Nobody makes forks like that anymore, hence the lack of google results. 

Also, that steerer tube in the photo looks to be steel, and should not be replaced with aluminum.