Disc 400 + 4 × 300
A Ø400 disc with four Ø300 discs glued centrally on top: a 90 mm step with a 50 mm ledge all round.
Interactive 3D model
Assembling the step
Mark the centre and a Ø300 circle on the Ø400 base. Glue the four Ø300 discs into a pack, then glue the pack onto the base along the marks with wood glue across the whole contact area and clamp through flat pads; follow the adhesive's curing time. Finish the edges after gluing.
Optional 4 × 30 mm screws from below through the base into the lowest Ø300 disc (3–4 pcs, at least 40 mm from the Ø300 edge, heads countersunk) are supplementary only, not a substitute for glue and clamps. Hardware is not modelled. One sheet of Ø400 discs (9) and one sheet of Ø300 discs (25) yield 6 steps, leaving 3 bases and 1 Ø300 disc.
Cut the disc with a router on a trammel, on a CNC from the DXF (one circle on layer CUT, centred on the origin) or with a jigsaw along a marked circle, then sand the edge. No chamfer is modelled; file a 2 × 2 mm chamfer by hand if wanted and sand the top face.
A thin disc slides on a smooth gym floor: protect the underside with a rubber pad or anti-slip coating. Use birch plywood and seal the edges.
Geometry draft, not a tested sports apparatus. Glue-joint strength and stability when landing on the rim of the top disc are untested; glue thickness is excluded from the height. Check the bond, the edges and the floor surface before training.
