Lay the spacer tube on top of the press plate, align the sides and make the back edge flush.
Insure all edges are tight and squared; this piece is critical, it must be a uniform height throughout the entire item. Grind off any imperfections.
Tack weld the two together in many places (at least 3 on each seam).
Double check everything for squareness!!
Weld the two together on all edges where they touch
It is a good idea to weld in 1” or 2” increments, skipping around to different places to prevent warpage. You will need to weld multiple layers where the tubing is rounded.
Lay the spacer/press plate assembly down so the press plate is touching the table.
Align side pieces with spacer and press plate assembly.
Insure the two are square vertically and horizontally with the spacer, that they are parallel, and that everything is touching the table.
It helps to use angle iron tacked to your table and the sides, so it insures they are vertically square. This also makes it a bit easier to align everything else. Video Help
Also, it may help to use paper shims (see between the sides and the tube to properly space them. Video Help
Tack the sides to the tube on all sides in multiple places except where it is touching the table. Add a few 1" seams to prohibit them from moving.
Do a few light tacks first, and double check it's still square. If not, grind off the tacks and start over.
There cannot be any outstanding bumps or welds anywhere; the drawer will be sliding in and out of a tight spot and bumps will catch on the frame crossmembers.
Make sure there's no welding spatter where the rollers will be rolling. Grind any off with a small grinder
