Gather materials for the “Jig”; this means 6”x12” tubing (52”) and any extra heavy U Channel. If you don't have any laying around, you can use one drawer member, and one spacer on each side.
Clamp the vertical pieces to the "Jig" on each end, with extra U channel in between the tubing and the vertical pieces.
Make sure they are both orientated properly, that is that both roller slots are at the same end of the jig.
Insure the two verticals are flush at the top end.
Clamp one horizontal member at each end of the jig.
Make sure they are flush with the ends of the verticals and centered on them.
Insure they are square with the jig by using a large square.
Clamp using 1 or 2 vise grips on either side.
If you didn't need to use the drawer members for the jig, you can drill those and the wide cylinder support holes now too so you won't have to handle the material twice. See below for how to do it.
It really helps to label each member, so that if you end up unbolting the piece later, you'll know exactly where it goes and in what orientation. Mark which side will be the top of the machine, and which member goes where.
Use a Mag-Drill to drill the 3/4" holes each place where the horizontal members overlap the vertical members.
Before drilling, double check that when the holes go thru the vertical members, they will be on the lip of the U-channel, not going into the wall, or off of the lip.
Bolt the horizontal members tightly to the vertical members.
Flip the jig over so you have access to drill the other holes. See video for help.
Double check to make sure everything is still square.
If not, loosen the bolts and square it up on what you labeled top first and tighten those bolts. Then square out the other side and torch out any spots prohibiting the bolts from going thru.
Bolt it back when you're done.
Step #6: Mag-Drill the holes for the wide cylinder supports and drawer members
