Remove the bar stool pieces from the box. Lay out the pieces and hardware in an organized manner with all like parts grouped together. Your bar stool will have either: 4 legs or 2 leg-frame combinations. The leg-frame combination may not require leg braces because of the shape of construction.
Squirt a pea-sized dollop of wood glue into the pre-drilled holes in the legs of a wood bar stool to better secure the leg braces. Metal stools won't require glue.
Insert the leg braces into the pre-drilled holes (joints) on the interior sides of the legs. Some bar stools will require the leg braces to be screwed to the stool legs into pre-drilled or partially drilled holes. Bar stools generally have between 2 and 4 leg braces or none at all. Typically, leg braces fit between the 4 bar stool legs, and some bar stools may have 2 leg braces on each directional side (north, south, east, west) with a smaller brace being inserted between the legs closer to the top of the stool, and a slightly longer brace being inserted closer to the center of the stool. Metal stools sometimes feature a metal ring that is inserted inside or over the leg-frame and attached with screws.
Wipe away any excess glue that seeps from the holes/joints around the leg braces with paper towels.
Attach the backrest to the stool seat base if applicable. Many bar stools do not have backrests. According to Free Patents Online, the backrest is a separate piece that may or may not also screw to the back of the rear legs of the bar stool as well as to the stool seat base.
Turn the stool seat base with the underside facing up and the cushion seat portion underneath. There should be pre-drilled holes visible on the wood or particle board that is the underside of the stool base. If you have legs that insert into the seat base, proceed to the next step. If you have a leg-frame combination, skip to Step 8.
Insert and screw the legs or leg frame to the stool seat base. Many bar stool manufacturers include Allen bolts and an Allen wrench instead of screws. An Allen wrench resembles a metal L. Allen wrenches can be purchased at hakrdware, automotive, discount and home improvement stores. Skip to Step 9.
Place the bottom leg frame under the top leg frame. There should be an indentation or notch where the legs fit together. Insert the bolt(s) through the pre-drilled holes to connect the two frames. This style is more common with stools featuring metal legs. There may be another plate that attaches over the leg-frame before you affix the frame to the seat base.
Tighten all screws with a screwdriver (or Allen wrench if applicable). Stand the bar stool upright. According to Richardson Seating, most people find it only takes about 15-minutes to put together a simple bar stool. More involved stools with backrests and arm rests and/or swivel capabilities will take longer and have more complicated instructions.