Zip Line Pulley

A zipline is a pulley device designed to ride a rope or wire using gravity as propulsion.  There is usually 2 or more pully type wheels that sit atop the rope and guide the device along the wire.  This instructable will show you how to construct one.  Keep in mind this is an informational instruction and the author holds no responsibility for the use or outcome of your device.  I can only show you what worked for me.


Matereals

1   16 - 20 ga sheet metal
2    1/4" x 4"  steel pipe
1    1/4" pipe connector
2    Pulleys
2    Rollerblade/skate board bearings
2    3/4" rubber 'o' rings
2    3/16 x 1 1/4" bolts
4    3/16" nuts
2    3/16" lock washers
1    Tube of grease


Tools

Drill (1/4" drill bit*)
3/16 drill bit
Dremel (small sanding attachment)*
Crecent Wrench or Pliers
Metal shears/ Tin snips
Hack saw
Permanent marker
Ruler
* You will not need this if you have a 1/2 " drill bit, except for some fine tuning.  This is just what I used.

Step 1 Preping Matereals

I used only 2 pullys since this is the minimum needed for stability of this device.  You don't need the whole pulley, just the wheel, so you must remove this from the rest of the unit.  This is a 1 1/4 inch wheel in the middle of the frame.  I extracted this by putting the blade of the hack saw through the arch of the pulley, refastening it, and sawing off the pulley axel from the inside.  Do this for. both pulleys, or however many you choose to use.  The more pulley wheels you have on your device, the less friction there will be.  In some cases this may not necessarily be a good thing, because less friction means more speed with the inablilty to brake.


Next you must outline your frame design onto a piece of sheet metal.   I used a somewhat triangular pattern.  Its important to have accurate measurements because balance is key for a device such as this.  My measurements were 4.5" x 1.5 " x 2 1/4 x 1" x 2 1/4 x 1.5 .  I did this for both pieces, and measured the spots where I would drill holes for the axels and handels to go.   I placed my axel holes; down  3/4" from the top.  From left to the center of the axel hole is 1 1/8 " and the space to the next axel hole is 2 3/8 inches which leaves you with 1 1/8" to the right side of the frame.

The hole for the handel I measured from the top which was 4.5" across.  I marked my 2 1/4" point and drew a line down to the bottom area which crossed at 1/2".   I measured 1/2 " up the line I had drawn and marked the center of where I would drill the hole for the handels.  After you drill the 1/2" hole for the handel, you will have about 1/4" left between the bottom of the handel and the bottom of the frame.


Last thing you need to prep is the pulley wheels.  All you need to do is add a generous amount of grease to the center.  The grease will reduce the friction of the wheel rubbing against the threads of the bolt.  I used white lithium grease on mine, and it seems to work well.