Building the equipment
The in-ground H4 treated Alkaline Copper Quaternary (ACQ) posts are routered at the top with a 45º cutter and ball-bearing guide to chamfer 10mm from the top. Use galvanised pipe with 25mm internal diameter, laying it across four 90 x 45mm timber supports to cut with a hacksaw or small angle grinder with a metal disc.
Anchoring the posts
Each station needs about 40 kilos of concrete to set posts in the ground.
Excavate the holes using a petrol-powered post-hole digger with a 200mm-wide auger. Make the sit-up bench holes 400mm deep and holes for the other stations 600mm deep. TIP Two people were needed to operate the digger we hired from Kennards (www.kennards.com.au).
Pour a bag of rapid-set concrete into each hole and add water, mixing with a length of timber for even consistency. Add another bag and more water to bring the concrete up to ground level, using a trowel to bevel the surface away from the posts for runoff.
On opposing sides of the head posts, use a 35mm speed bore bit to drill 75mm-deep holes 100mm and 158mm from the top, and 775mm from the base (see Diagram). On the foot posts drill 35mm holes 100mm from the top.
Assemble the bars
Excavate the post holes and position the assembled end frames in the holes, packing the base pipe rail at the head to 175mm above ground level. Temporarily brace the posts, plumb and set the post tops level.
Secure the pipe and posts
Loosely secure the pipe to the posts with cuphead bolts. Position a spirit level on the pipe to adjust the depth, check the spacings then tighten the bolts with a spanner. Pour rapid-set concrete into the holes and leave it to firm around the posts.