This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
Here are instructions on replacing with a spring seat the wooden seat of an armchair. Remove the wooden seat, and fix three battens across, 3 in. wide by 7/8in. thick, to act as spring rails. If the seat rails are 2in. deep, nail on the top all round pieces of stuff, 1 1/2 in. thick, for stuffing rails (see sketch). These rails should form a rebate, as shown. Six 8-in. upholsterers' springs will be required. These are secured to the spring rails with 3/4-in. staples placed round the bottom coil and driven into the wood. A cover of coarse canvas is put on the top, and tacked fast at the front; then pull the cover down at the back until the springs are compressed by about one-third of their length, and tack them fast in this position. The springs are securely stitched by the top coil to the cover with strong twine. Loop the edges with twine and fill them hard with well - pulled fibre or rag-flock, cover with scrym, and blind-stitch, and fasten with not less than three rows of stitching. Fill up with flock or hair, well picked on, and cover with sheet wadding, cased in with unbleached calico. Any staining, polishing, etc, should be done before the outer covering is put on.
Should the covering be of leather or leather-cloth, finish the edges with leather banding secured with brass or leather-headed studs; if covered with soft material, such as velvet, repps, etc., run a narrow scroll gimp round.
Putting Spring Seat in Armchair.