How to make a concrete seat

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Step 1.5   Aligning and bolting the leg forms to the seat form

The purpose of this step is to allow for easy alignment of the leg forms over the seat form during the casting process.
The casting process involves half-filling up the seat form with concreteA mixture of sand, gravel, water and cement which hardens to a stone like condition when dry., placing in the reinforcing, filling the seat form with concrete, and fixing the leg forms in place ready for more concrete.
It is the latter stage that is made easier and quicker with the addition of the angle brackets.

Do this step in the following order:

Measure 4⅜” (110mm) along pieces (c) from the inside corners of the seat form and mark across pieces (c). See fig.1.

Place the leg forms against the mark. Ensure that the leg forms are equal distance from the sides. Mark the drill holes on pieces (c) through the holes in the angle brackets. (See fig.2.) Then remove the leg forms.

Drill down into pieces (c) to a depth of ½” (12mm) with a 1⅛” (28mm) diameter drill bit, and then continue the rest of the way through with a ½” (12mm) drill bit. (See fig.3.) There will be four holes in all.

Insert a ⅜” (10mm) coachAre round headed bolts with square shoulders that resist rotation when located or driven into place. They can be called coach bolts or carriage bolts depending on which part of the world you live in. The head end of the bolt does not need a washer, but the other end of the bolt (the nut end) usually does./carriage boltA metal rod that has a head on one end and threads on the other and is used to fasten together lumber. The most common bolts used or referred to in projects within this website are coach/carriage bolts and hex bolts. into each hole from underneath and secure each bolt with a washer and nut. The nuts will finish below the surface of the woodTimber, lumber. The hard fibrous lignified substance under the bark of trees. See fig.3.

*Note:   The angle brackets are to hold the leg form to the seat form. They make for easy alignment when it comes to assembling the form for casting. The bracket size given above is not absolute. Anything similar will do as long as it does the trick. You may have to make your own by cutting, bending, and drilling a piece of sheetAny broad, thin surface. metal. On the other hand, you can do away with them altogether and use clamps to hold the leg forms to the seat form. The latter method however, will require a bit of extra measuring and aligning when it comes to assembling the forms for casting.