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--- magic_carpet_ptv_build_process [2016/06/07 23:50] – santiagoricoy
+++ magic_carpet_ptv_build_process [2016/06/08 01:12] (current) – santiagoricoy
@@ Line 190: / Line 190: @@
 The PTV steers by braking one side or the other of the differential. This transfers more power to the side that is not being braked, and thus the vehicle turns in the direction of the track that is being braked.
-//steering video//
+{{youtube>n63DFFF4ufA?medium}}
-.) [[Putting together Wheels and Tracks]]
+====Let's begin track construction!====
+So what are the tracks actually made of?
+Well, regular used tires (new ones may be utilized, but it's unnecessary).
+{{:ptv:ptvtires.jpg?nolink&300}}
+Sourcing used tires can possibly be quite difficult. I was looking for used tires shops, where you can actually purchase used/refurbished tires. People seeking used tires for their vehicles often have tires that should not be refurbished, and will be thrown away; that's where you come in. If you're up for the adventure, lots of people list free used tires on sites like Craigslist as well.
+I got lucky that a friend was throwing away tires for a shop. A couple were given to me. For this design I needed an inner tire diameter of at least 30 inches or so.
+Once we have procured our tires, we'll need to cut them.
+The tracks need to be a bit more than 6 inches wide with this design. So we can't just cut off the sidewalls (it's easy to do that with a razor blade though.).
+{{:ptv:ptvtirecuttools.jpg?nolink&500}}
+We will actually cut all the way around the tire's tread to make a belt. That sounds insane, yes, but it is possible. I found the best tools to use are metal cutoff wheels on an angle grinder (I recommend AGAINST the cutoff wheel though), a jigsaw, or an oscillating saw. I recommend the oscillating saw; they generally have more power.
+You'll also need a drill with a sizeable bit to make a hole in the tire. This is necessary to give your saw blade a place to start.
+{{:ptv:ptvdrilltires.jpg?nolink&500}}
+Get several blades as the tires will eat them all. Specifically, you'll need metal cutting blades with coarse teeth.
+I used these:
+{{:ptv:ptvsawblades.jpg?nolink&500}}
+T118B T-shank blades for the jigsaw, and course metal cutting blades for THICK metal for the oscillating saw.
+Tape, or mark somehow where you want to cut, and follow your line around the tire. I used tape.
+This WILL take up a lot of time.
+ **WEAR SAFETY GEAR FOR THIS PART**
+The blade heats up and sends molten tire bits into the air. If using a cutting wheel, they may become unstable and explode; shrapnel is not fun. Also, the steel wire inside the tire WILL slice you without protection. My arms began to turn red while I was cutting, as if I was being hit by something. All that was being done was violent shaking.  Heads up: wheel, jigsaw, or oscillating saw, they are all very uncomfortable, so take frequent breaks to let your hands and arms recover; check your tool blades, and so on.
+{{:ptv:ptvcuttirestape.jpg?nolink&500}}
+Once cut, we want to make the tracks a little safer to handle, so use an angle grinder to grind off the wires sticking out of the side of the cut tires. This also lets you smooth out the edges and make them a little straighter, for aesthetic purposes.
+{{:ptv:ptvgrindtires.jpg?nolink&500}}
+===Track Guides===
+The track guides are each made of 9 pieces.
+These are:
+  * a piece of pvc conduit (3/4" should work)
+  * a piece of smaller diameter low pressure water piping
+  * 2 flat washers
+  * 2 countersunk washers
+  * 1 carriage bolt
+  * a lock washer
+  * 1 nut
+Here is a visual, which is much easier than explaining it in depth.
+{{:ptv:20160529_212812.jpg?nolink&500}}
+The bolt goes through the tire.
+{{:ptv:ptvtirebolts.jpg?nolink&500}}
+Before that though, you need to mark where the bolts will go through. The first side you install on should placed such that the conduit will be within the area of the tire, not extending beyond the edge (so about a half inch from the edge of the tire).
+To space them around the tire, you don't want them right next to each other. About 40 guides are appropriate for our dimensions, but this design works in general with about 2.5 inches from bolt center to bolt center. Use a square to mark lines all the way around the inside of the track.
+It was recommended to use a paint marker, but a chalk marker, or permanent marker in silver also works. I could not find any one of those, so I used a bit of Elmer's glue like a pen and it worked just fine.
+{{:ptv:ptvtirelines.jpg?nolink&500}}
+{{:ptv:ptvglue.jpg?nolink&500}}
+The rest goes on the inside, with the lockwasher and nut tightening it all down. The idea is for the slightly longer piece of pipe to mushroom on the ends, allowing the piece of PVC conduit to slide around it as it rubs against the wheels of the vehicle.
+{{:ptv:ptvtrackguides.jpg?nolink&500}}
+The wheels will roll in between the two rows of track guides on the tires. With the wheels I've used, a space of about 4 inches between the two rows seems to work best.
+{{:ptv:20160607_150354.jpg?nolink&500}}
+====End Notes====
+I found that in the end, if basing another project off the same principles, you'll likely have a few issues.
+The first is that the brakes need to be bolted in a place such that they have a solid bite. I had to space my wheels up, and that compromised the bite of my calipers.
+The track guides **NEED** to be spaced correctly. I am losing way more track guides on the side with a half inch less space between rows than the other. The whole track could suddenly fall off this way.
+The wheels used to drive the tracks will probably get torn apart fairly quickly, but they seem a lot more like a consumable than a permanent part anyway.
+====Exclamation Marks!!!!!!!====
+Let's see the test run!! It wasn't supposed to be amazing. I just wanted to demonstrate it running, turning, and most importantly...stopping.
+{{youtube>Fv0zKvxnA9I?medium}}