Cut inside frame ends to match width of inside the cage, and put in position. Predrill and screw through frame sides into inside frame ends using 100mm batten screws. Repeat for opposite side.
Use bolt cutters to cut out cage bottom. Use a metal file to round and remove any sharp edges that could hurt guinea pigs.
Cut cover side to height of cage. To create angled shape, measuring from 1 long edge, mark points 120mm from edge at bottom and 350mm at top. Draw a straight line between these points and cut along with power saw. Repeat to create other cover side.
Cut cover top to width of cage plus 108mm (the combined thickness of all cover and frame sides). Butt top edge of cover side into cover top flush with 1 end. Predrill and screw through cover top into side to secure. Repeat to attach to other cover side.
Cut cover brace to width of cover top. Put brace against bottom corner of cover side. Make end of brace flush with outside face of both cover sides and screw through brace into sides.
Put assembled cover over 1 end of cage so cover brace is hard against frame end. Predrill and screw through cover brace into frame end and through bottom of cover side into frame side.
Cut corners off 1 handle arm on 1 end to round. With cage on its side, put handle arm on cover side on an angle so uncut end runs past frame side about 2⁄3 of the way along cage and rounded end runs past cover side. It should sit 1m off the ground when cage is upright.
To cut off excess handle arm, mark line of frame side’s bottom edge on handle arm. On cover side, mark where handle arm sits. Remove handle arm and cut along angled line on handle arm. Repeat with other handle arm.
Put handle arm back on cover side so it meets marks made in Step 8. Predrill and screw through handle arm into cover side. Use offcut of handle arm to create a block to fill gap between handle arm and frame side. Screw through handle arm and block into frame side. Repeat with other handle arm.
Cut handle to width of cover top. Put between handle arms, 100mm from rounded end. Predrill and screw through handle arm into handle to secure. Repeat for other end of handle.
Put mower wheel against cage so bottom of wheel sits 25mm below bottom of frame. Screw through wheel’s axle hole into bottom of frame with 100mm batten screw. Don’t over-tighten screw so wheel can turn. Repeat with remaining wheels.
Screw mower parts to cover sides and top to give cage the mower look.