“When my twins (Ben & Abbey) asked for a Zip Line for their 10th Birthday, I thought they were crazy! They tried zip lining at a local adventure park and have been hooked ever since. My husband and I started doing some research and came across your website. Before we knew it, we placed an order for a kit complete with the 150 ‘ of cable, pulley, wood seat and breaking system. My husband (George) built a platform up in a tree with a ladder starting from the base of our playscape…that was the hardest part of the project. He then installed the zip line components in no time at all.

We had about 15 kids over the house for a birthday party. The kids “zipped” for four hours straight. Many of the parents couldn’t resist and had to try it themselves. The parents were saying that the kids will be talking about this party until they graduate in 8th grade! Some of the kids were hiding when their parents came to pick them up because they didn’t want to go home.

Thank you! My kids said this is the best birthday present ever!”

We had fun this week! The Ziplinegear.com team went outdoors to enjoy some of the beautiful spring weather we’re having, and ran a series of speed tests on our pulley lineup. We set up a 300′ zip line out in front of our warehouse and sent a 175lb reel of cable down the line about 50 times, timing how fast the different pulleys could carry it. We’ll be using this information to find the friction coefficients of each pulley and predict exactly how fast a specific pulley will come in at the end of a given zip  line. Fun stuff!

Check out the rest of the pictures on our facebook page.

What:
The bungee brake consists of a high density plastic block that is assembled on the cable but is free to slide up and down. A bungee cord is then connected from the block to an anchor point (usually a tree or post) off to the side of the zip line, near the end.
How:
When the rider comes zipping in on the cable the pulley will make contact with the block and push it down the line. As the block is pushed the bungee cord is stretched and provides resistance, slowing the rider to a gentle stop near the end of the cable.

How do I know if I need a bungee brake?

Installation instructions:
1) Assemble the two plastic blocks onto the cable using three standard bolts and an eyebolt.
2) Attach the rubber bumper to the block, making sure the pad faces the top of the ride (so the pulley will hit the pad).
3) Using a quick link, attach the bungee cord to the eyebolt in the block.
4) Drill a pilot hole and screw your eye lag to a tree or post at least 10 feet off to the side of the zip line. Use your other quick link to connect the bungee cord to this eye lag.

Our launch platform is free-standing and constructed of pressure treated lumber (2 x 8′s, 6′s and 4′s) using galvanized fasteners (16d twist nails and heavy lag screws). The zip line uses a classic arresting block and 1/2 inch marine-grade shock cord anchored to a third tree (tangentially) to the main cable at around the 55-60 foot mark. We use separate shock cords for “kids” and “adults”. There is no landing platform as the arresting block and cable actually return the seat and rider to almost the initial contact point and riders simply hop off the seat. We are working on a seat return system as the next feature. Following a ride, we currently clip a line to the seat and walk it back up to the launch platform. Speed is good at maybe 15 or so mph. Despite the relatively short length the ride is exciting and pre-flight safety checks keep riders (the “thrillbillies”) healthy.

The zip line statistics are as follows:

Top anchor height:         12.5 feet

Lower anchor height:        8.5 feet

Cable length:                         70 feet

The top anchor uses an 8 foot cable sling, pressure treated blocks on the circumference of the tree, galvanized fasteners, a 12 inch turnbuckle, and safety chain. The lower anchor uses the same blocks and cable clamps only.

Here are few photos and a sketch of the zip line:

It has been an exciting week for the team here at ZipLineGear.com! As the summer sales have tapered off a bit, we’ve had some time to work on the products you’ve been asking for.  Following close on the heels of the Quicksilver and Viper zip line pulleys we’ll be rolling out some new pre-made bungee brake blocks, commercial riding kits, and a brand new line of Jumbo-size zip line kits for those of you who keep asking for the 250-1000 footers. Stay tuned!

So what’s new for this week? (drumroll please)       …Cable tension kits.

One of the most difficult aspects of installing a big zip line is stretching the cable from one anchor to the other. You typically have a turnbuckle on one or both ends for minor adjustments, but that does nothing to help get your 100lb length of cable stretched to the other side. The problem is illustrated by our friends Bob and Joe, the Stick brothers…

Bob and Joe Stick have prepared their anchors and are trying to stretch their zip line cable from one pole to the other. Joe Stick soon realizes that the cable is far too heavy for him to pull it across.

Joe fumes in frustration, but his brother Bob Stick remembers an article he read on the ZipLineGear blog about using a come-along and a cable grab to tighten zip line cables.

Bob and Joe resume their work, after stopping by the ZipLineGear warehouse to get one of their new Cable Pulling kits. The $149.95 price tag seemed pretty expensive for only using it one time, but once they found out that ZipLineGear offers an 85% refund for installation tools returned in good working condition, they figured it was well worth the $22.50.

Joe, having attached the cable grab to the main line, watches in admiration as Bob cranks it tight with the come-along.

Bob terminates the cable on the second anchor without breaking a sweat while Joe puts the pulley on the cable.

The pull kit has been put away and Joe volunteers to take the first trip down the zip line…

…and it looks like Bob and Joe Stick will be picking up a bungee brake when they return the pull kit.

]]> http://ziplinegear.com/blog/equipment-reviews/some-tips-on-tightening-a-heavy-zip-line-cable/feed/ 0 http://ziplinegear.com/blog/customer-projects/camp-coyote-zip-line-adventure/ http://ziplinegear.com/blog/customer-projects/camp-coyote-zip-line-adventure/#comments Fri, 27 Feb 2009 01:59:24 +0000 admin http://ziplinegear.com/blog/?p=42

Nathan, thanks for the great website.  Here are zip line pictures from our website, www.farmhouselife.com.  Farmhouse Life is our farm-based campground in central Iowa located near the Raccoon River Valley Trail.  We have a bunk house, shelter house, mess shed, a pool in a grain bin, and a zip line for kids with more plans in the works.  The zip line is 80 feet long with a 10 foot long sand trap for stopping.  The “launch platform” is less than 4 feet off the ground but the kids think that the first step off the platform is a great adventure.  More pictures are available on the website.

The zip line is hugely popular and the “deals” that determine who gets to go next are funny to observe.  Two adults are constantly on the move returning the trolley and putting on safety harnesses but the kids have a blast.

Our son Jake in full safety harness about halfway down the line.  We tried a seat tethered to the trolley but the kids like to have their feet swinging free.

Our niece Bailey heads down the line while Ian helps keep order on the launch platform.

This 200′ Mammoth Deluxe kit was installed over a large pond in early 2008, right here in our beautiful hometown of Grants Pass, Oregon. The kit was slightly customized to fit the location; the bungee stop was removed since we could drop into the water or coast to a stop before reaching the far end, and a full line of attachments were added to allow multiple types of riding.

The zip line starts about 20′ above the surface of the water. The Mammoth Deluxe kit uses an 8′ cable sling to wrap around the tree on each end and connect to the cable with a 12″ turnbuckle.

The cable ended being far too slack for the first run, and the first ride ended abruptly, with our test rider drenched and sitting on the seat in about 10 inches of water in the middle of the pond! We tightened it up a bit and tested it again- standing on the seat this time!

We eventually tuned it to where the seat would hang above the water, just high enough to reach down and skim the water as we zipped across.

We put the younger kids in a climbing harness and swung them around over the water with the return line (3/8″ braided nylon rope), before pulling them back to dismount at the top.

The 20″ straight bar was great for dropping off- it’s weight (about 5 pounds) keeps it from bouncing around too much when someone lets go. Even so, our favorite was the dual handlebar; it doesn’t rotate like the straight bar does…

…and you can ride it upside down and backwards!

We also found that having a lot of slack in the cable allowed us to swing people side to side over the water, using the return line. This ends up being even more thrilling than the straight ride down- it’s a giant swing over the water.

One of the guys finishes a back flip off the zip line seat.

This is a short video of the zip line in action!

Have you ever tried tying a knot with steel cable? If you haven’t already- don’t bother. Tying off a steel cable requires the use of cable clamps, otherwise known as wire rope clips. The cable is folded around something called a thimble, or a tree in some cases, and is clamped back to itself with three of these nifty clamps. It goes something like this:

Step 1: Turn back the specified amount of cable from the thimble. Apply the first clip one base width from the cut end of the wire rope (U-bolt over cut end – live end rests in clip saddle). Tighten nuts evenly to recommended torque.

Step 2: Apply the next clamp as near the loop as possible (when using a thimble). Twist on nuts firmly but do not tighten.

Step 3: Place the third clamp equally between the first two, take up the slack, and tighten all nuts evenly on all clamps to recommended torque.

Step 4: Perform a weight test on the cable and retighten all clamps to the specified torque- cable will stretch and shrink slightly when tension is applied.

The following table provides the recommended torque for each size cable clamp; if you don’t have a torque wrench, just keep them tight and check periodically for slippage.

Cable clamps can also be used to create a loop around the entire anchor, instead of just a small loop for hardware connections. It’s pretty straight forward- I think the only concern is to make sure the cable loop doesn’t come out from the first clamp at too large of an angle (keep the first clamp a reasonable distance from the tree/pole).