Style #18650, 18700.
All attachments use #8 x 1 1/4" wood screws. Be sure to pilot all screw holes.
All wood is solid hardwood 3/4" thick (although the 2 wood cleats may be thicker to make screwing boards to the bottom edge of the cleat easier). Maple or Oak is a good choice. (cleats may be Poplar wood) No plywood. Avoid Pine and "Whitewood" as they are too soft to resist screw tear out. Obviously, no particle board. When certain of wood placement, glue and screw is always best.
Install a 1"x 4" or thicker wood cleat using wood screws to the front and rear chair rails. The bottom edge of the cleat should be 7 3/4" from the bottom chair edges to support the following 2 boards.
Attach a 1" x 2" or wider from front to rear at underside edge of the two installed cleats. These should be in line with the flat 2" wide metal glider flats. Install 2 screws into each and test installation to make sure glider was installed at correct height and chair does not interfere with glider.
Style #18100
All attachments are a minimum of #8 x 1 1/2" wood screws. Be sure to pilot all screw holes.
All wood is solid 1"x 4" hardwood 10 3/4" long. Poplar, Maple or Oak are good choices. No plywood. Avoid Pine and "Whitewood" as they are too soft to resist screw tear out. Obviously, no particle board.
Determine the total wood blocking needed by setting assembled unit into chair cavity midway to front and back. Push assembly bracket over to 1 side. Measure empty space to the bracket on opposite chair side and divide in half. That number is the blocking thickness needed for each side.
After screwing all blocking together, install/tighten 1 bracket screw each side using the center hole (5 holes each side) of the bracket 3 3/4" from the bottom edge of the chair side. Level the chair and install a screw at front and rear of each bracket. Test chair to make sure of clearance. Adjust as necessary if needed and install all screws.
When using multiple wood pieces on a side, it is best to glue and screw each piece to the previous piece rather than screw 2-3 wood pieces at one time.