The infinite monkey bar, start to finish

The infinite monkey bar: breaking down where it comes from and how it’s made.

Long post alert. This is a stupidly long post meant to document all the steps in making our infinite monkey bar.

Here’s a breakdown of all the steps in making the infinite monkey bar

1 Procured from scrapyard: Two 20 inch diameter circles weighing 9.5 kgs each. 8 inch piece of 90 mm diameter OD pipe with an ID of 69 mm. I also lucked out with 60 mm outer diameter 51 mm inner diameter pipe. This is used to create a fixture that will fit into our existing pull up rack.

2 Procured as fresh material: 160 inches of 30 mm rod. 56 inches of 40 mm rod.

3 Lasercut 20 inch circles into 19 inches with 9 holes. A big one in the middle for the 40 mm rod and 8 small ones in periphery for the 30 mm rods. We also cut 8 small fixtures to weld the 30 mm rod onto to connect the two circles. These were lasercut to match the shape of the circle and the hole pattern.

We also commissioned two heavy duty 10 mm thick brackets that were folded to wrap around the pipes that fit on the existing pull up bar frame. These were first cut with 36 mm holes to accommodate the central rod. And then folded precisely to line up the holes.

4 Machining the central rod. The 40 mm rod was turned on both ends to 35 mm for a distance of 12.5 inches. This distance was estimated based on the distance between the two brackets and to accommodate the clamps, circles and wheels with the bearings.

5 We picked up SKF bearings that are 70 mm in diameter and are meant to fit around a 35 mm rod or pipe. These bearings were made in Malaysia.

6 More machining. The four wheels were machined to fit a bearing and hold a bushing that would fit on the 40 mm rod. In case the bearing failed. These were cut from a single pipe before being machined to accommodate the bearing. The entire mechanism would rest on these wheels.

7 Welding. The wheels were welded onto the circle. The bearing were fitted. The entire wheel-circle was fitted onto both sides of the 40 mm rod. The 30 mm pull up bars were then welded onto the clamps. The clamps were fitted using 16 pieces of 12 mm nuts and bolts (3/4 of an inch long). We also welded the 10 mm thick clamps on the 60 mm pipes and added a gusset to reinforce the whole thing.

8 Fitting. The clamps were attached and the unit lifted by 3 chaps (me included) and slotted onto the pull up bar. Four 3/4 inch sizes nuts and bolts were then fitted through to secure it in place.

9 All the nuts and bolts were tightened and the games began.

Point of this post. To show you how hard it is to make things :D Almost all the stainless steel in this product is Indian. Some of the scrap steel is Chinese or Japanese. All the nuts and bolts were made in India. The TIG welding machine, laser cutter and press brake were made in China. The machine used to bore the wheels and 40 mm rod were made in India. Made in India is never really made in India. Everything is made on Earth.