Making a tightrope
I’ve mentioned my daughter’s fire twirling before (more on making firestaffs later) but this weekend’s project was to make a portable tightrope so that my daughter’s circus skills could be extended a little. For those, like me, who searched the net in vain for instructions on making a tightrope, here’s the way I made one. First up; the disclaimer – if you follow these instructions I take absolutely NO (zero, zip) responsibility for anyone hurting themselves or their property – I have no control over your standard of workmanship, the quality of materials or the manner of usage – so you do this entirely at your own risk (so don’t sue me okay?).
Now the fun stuff. Take 9.4 metres of 50mm square section galvanised steel tube. Add one 10mm turnbuckle, one 10mm ring bolt with 2 washers and nut, 2m of 5mm wire rope, two 5mm rope thimbles, four 5mm U-bolts, two 2½-inch three-eighth inch bolts with nuts and washers; twelve 2½-inch quarter inch bolts with washers and nuts; and finally, six plastic end-caps for the 50mm square tubing.
Tools: one angle grinder with metal cutting blade (you could use a hacksaw, but it would take a lot longer) one portable drill with three-eighth and quarter inch drill bits; a pair of pliers; spanners for the various bolts and nuts; and a small lump hammer – for added persuasion.
Safety gear: full face mask, hearing protection, leather gloves (or wet cotton ones while cutting) and a leather apron (you don’t want to cook your privates!) and leather safety shoes – this is serious metal fabrication!
Time: one weekend.
Instructions: First, cut the steel tube to the following lengths:
one at two metres
four at one metre
two at 70cms (0.7m)
four at 50 cms (0.5m)
Take the two 70cm bits and cut out opposing sides leaving two legs long enough to fit over one of the 1m pieces at the halfway point so that they meet like a T. When it is snugly mated, drill through and fix with a quarter inch bolt. Do the same with the other 70cm piece and attach it to another of the 1m pieces. This gives you two T-shaped parts which will be the uprights and the feet.
Next do similar cutouts at both ends of the 2m part, then attach it to the uprights just above the feet.
Now do similar cutouts at each end (but only one side) of the four 500mm (0.5m) parts -these are the triangulating braces for the uprights. Make the cutouts deeper at the lower end to allow for a shallower angle (about 30 degrees). Drill and bolt these to the side of the uprights and to the feet.
Now for the longer braces that make the truss structure. Make these with cutout as as for the braces supporting the uprights, but these 1 metre pieces will extend form the inner side of the uprights to near the centre of the 2.0 metre base. And drill and bolt these when they are in position. Now add the end caps to the four feet ends and the two uprights – this will make it much safer if you fall against one of the uprights.
The finished structure should look like this:
Now for the wire rope.
Drill three-eighth inch holes through the two uprights near the top. Attach a ring bolt to one end and the turnbuckle to the other, ensuring that you have washers on the outside where the nuts are to ensure a strong anchor – this is important, beacause you will be applying around three tonnes tension to the wire.
Open up the rope thimbles and insert them so that they straddle the eye of the eye bolt at one end and the eye of the turnbuckle at the other.
Feed one end of the rope through the eye of the eyebolt so that it sits in the channel of the rope thimble and clamp it with TWO U-clamps of the correct size.
Then do the same at the turnbuckle end, ensuring that the wire rope is pulled fairly tight.
Now tension the wire with the turnbuckle until you get a nice deep bass note – now that is tight, and you should be able to apply weight (gently at first) to ensure that everything is taking the stress okay, then do a test walk along the tightrope!
And here is the finished tightrope. Do use marine quality materials for the rope attachments – they might be a little more expensive, but you want to minimise the risk of things breaking at inopportune moments! Enjoy – and good luck 🙂
Cheers
Jerry
