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Instructions for Building a Soft-covered Flat

Flat frames are constructed from 1x3 lumber, however, the actual width of this lumber will vary. Before you can figure the lengths of the stiles, rails, and toggles of your flat, you must know the actual dimension to which your lumber was ripped. Typically lumber widths include: 2-5/8, 2-3/4, and 3.

Rails: Flats have two rails, a top and a bottom rail. These horizontal members run the entire width of the flat. 

Stiles: Stiles make up the outer verticals members of the flat frame, so two are needed. The stiles sit on top of the bottom rail, and the top rail sits on top of the stiles. 

Toggles: Toggles or toggle bars a placed horizontally between the stiles. Therefore, the length of the toggles is equal to the width of the flat minus the two times the actual width of the 1x3s. For soft-covered flats, the top of the lowest toggle is placed 3-0 above the bottom of the bottom rail. Subsequent toggles are spaced every 3-0.

Diagonal braces: Diagonal braces, or corner braces, are 1x3s that are placed at a 45 degree angle between the rails and one of the stiles whenever a soft-covered flat is wider than 3-0. Since the purpose of the diagonal braces is to prevent the rails from warping, no unsupported span of a rail should be more than 3-0. When a flat is wide and the distance between the top toggle and the top rail is short, the diagonal brace may have to be made it two parts so that the longest unsupported span of the top rail is 3-0 or less. 

Cornerblocks: Cornerblocks are right-triangular pieces of thick plywood used to join the stiles and rails. Cornerblocks sit back at least from the edges of the flats. Cornerblocks MUST be positioned so that the grain of the plywood runs across the joint. Sometimes cornerblocks are used to join toggles to stiles, and cornerbraces to stiles or rails. 

Keystones: Keystones are rectangular pieces of plywood used to join the toggles to the stiles. Keystones  MUST be cut so that the grain of the plywood runs the length of the keystones. 

Scabs: Scabs are keystones with one end cut at a 45 degree angle and are used to attach diagonal braces to the stiles and rails. Like keystones, scabs sit back at least from the edges of the flats.