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.
Drill the pipe holes
Chamfer the posts, sanding with 80-grit abrasive paper. Drill 75mm-deep holes using a 35mm speed bore bit, then position the galvanised pipe between the posts
Secure the pipe
Drill clearance holes through the pipe and posts, keeping them aligned, then slide in cuphead bolts, tightening the nuts with a ring spanner or a shifter.
Set the posts
Dig the holes and position the posts, adjusting the depth to make the bars the same height, checking with a spirit level along and across the pipes at the ends. Temporarily hold the posts and bars with timber braces while pouring the concrete.
Fitting the pipe into posts
Drill holes in post for the pipe by securing the posts and marking the holes. Using a power drill fitted with a 35mm speed bore bit, drill 75mm-deep holes.
TIP: Wrap tape around the bit 75mm from the end as a depth gauge.
Anchor the pipe in the posts by drilling a 4mm hole through the posts into the centre of the pipe, using a 10mm twist bit to create a clearance hole for the bolts through the post and pipe. Secure with galvanised cuphead bots, nuts and washers