Wire Rope for Climbing

Does anyone have a suggestion/supplier for a wire rope for a winch for climbing? Or if you have a suggestion for something other than wire rope, please let us know.

Thanks so much,

JMH

Though I would strongly urge against using this because of the safety hazard that it creates. Steel rope is very sharp and can end up injuring drive teams as they attempt to remove the robot from the field.

As an alternative you can probably a get away with the right rope or para cord.

There are lots of good ways to remove the safety hazard. Start by using coated cable. Also tape up the ends of the cable (or apply a crimp bead to the end) to keep it from fraying after it’s been cut.

If you are after a strong, circular rope shape, look up Dyneema rope - Dyneema - Marlow Ropes

It is crazy strong, virtually zero enlongation at break, and more than capable of holding your robot.

We initially used climbing rope last year, had some falls (from drivers overclimbing mostly), swapped out to 3mm (1200kg break strain) Dyneema in our second comp (we were initially concerned about its abrasion resistance - becomes significantly weaker once abraded), and then 4mm (2000 Kg break strain) after we realised our drivers sometimes got excited and climbed waaay too far and still managed to snap one. No issues after that (we later we also reduced the gearing ratio to increase our climb speed).

For any Aussie teams - Dyneema (R) High Strength Rope (SK75) Archives - Rope Galore is our preferred supplier - great prices, and mostly next day delivery in Sydney, AUS.

We have used this extremly successfully for climbers in 13, 16, &17 and for our launcher pull-back in 14.

http://www.samsonrope.com/Pages/Product.aspx?ProductID=872

Hint: Look for spear fishing line. We used woven kevlar rated for 900 lbs. It’s very light, slim and tough. If you need to replace once a day (in competition), NBD.

New England Ropes Spyderline is another good option for rope.

Similar to the other posts, Spectra Cable has been a FRC standard for years. Doesn’t stretch, easy to work with, light. This one has a working strength of over 1,000lbs but it comes is all sizes.

We’ve been using Amsteel Blue forever and love it.

thus far we haven’t found a use for the 6-5/8" with it’s 3.969 million pound proof load, but I sure hope to some day.

That sounds like a challenge.

I wonder…

Maximum energy you can get from a battery per FRC rules is 210,000 Joules in a match, where the energy required to break 3.969 million pound load rope would be 19,613,300 Newtons. Amsteel Blue stretches a maximum of 1%, so in order to break a 1 m long segment of 6-5/8" you would need to apply 196,133 Joules. So, technically, you could do it. Even if there’s no practical application.

You can buy wire rope from McMaster, but pricing is not the best. We bought a spool of wire rope from better pricing from e-riggings.com, but I am sure there are other vendors out there.

If you are going to use steel cables, I recommend going with the 7x19 constructions. That is the most flexible construction that I know of that you can buy from McMaster or any place without doing a custom run.

When working with steel cables, the minimum bend radius of the cable is often larger than you expect. As a rule of thumb, the minimum pulley diameter for stainless is 300 times the filament diameter. 7x19 has 15 filaments across its diameter, so the minimum pulley diameter for 7x19 stainless is 20 times the cable diameter. You can cheat this some, but it is advised against. Going under the minimum pulley diameter will accelerate cable fatigue and thus failure.