Here are pics. There are different ways to do this. This is just what I had at the time.
Depending on what size line you are using, start with a 3/8" PTC elbow on bag. Run your line into a 3/8 male PTC. Then a 3/8 union. Then a 3/8 to 1/8 reducing bushing. Then your schrader. (I think the schrader is 1/8 or 1/4)
If by chance you are using 1/4" airline, you can eliminate both the union and reducing bushing by using
this:
[IMG]http://*****************/images/products/mid_1-4_OD_x_1-8_NPTF_Female_Connector.jpg[/IMG]
Lots of different ways to do it...