Add a 3rd axle with 2 wheels on the middle of the cart. Make them sit a little lower than the end two axles. This way you can pivot on the middle axle but it can tilt and rest on one of the end two axles.
Look at a home depot 6 wheeled lumber cart for reference
RE the Home Depot lumber cart idea, I couldn't do it without doing multiple cuts with multiple unions (perhaps the next cart).
On sand, the rig was still a little hard to pull. On asphalt, I need a steering mechanism badly. There is a McMaster Carr cart hardware kit that includes wheels, axles, fasteners and steering assembly for $80 but I'm a cheapass. So instead of buying the kit, I spent way too much time and experimentation to solve the steering problem...
After lots of experimentation, I ended up using 5/8" threaded bar as a steering axle and a rotation point for that axle. I simply used a PVC pipe to mount the rotation point with the steering axle...
Stainless Nut bolt pack from Home Depot. ( I bought 3 of these.)
735bcbc4-a7a6-48e8-ad00-b2c0fed45af8.png (38.91 KiB) Viewed 812 times
Had to use the cart so I just attached a big caribener to pull the top of the cart.
d02e30df-3912-4110-a8c5-2ef244124a34.png (35.58 KiB) Viewed 815 times
Since the rotational point is about an inch away from the axle, as the car is pulled the wheels turn like in a Castor and the cart turns.
5cda99e1-2351-479b-9d75-9b0e38128582.png (36.64 KiB) Viewed 815 times
two 5/8" nuts and a washer (Strainless Steel) hold the wheels on (This will later prove to be a mistake.)
0107491a-957c-431c-94fe-b3e7578cc761.png (37.62 KiB) Viewed 815 times
Vertical load is spread across two horizontal pipes
3a0cfe6b-0abd-45f9-96ed-be358ba3be91.png (41.07 KiB) Viewed 815 times
Slicing off the unused threaded bar. (Sparks make me look cool)
f0b0c062-dc73-4112-82f4-e88a0c82deed.png (36.53 KiB) Viewed 815 times
Top view of rotation point
5cda99e1-2351-479b-9d75-9b0e38128582.png (36.64 KiB) Viewed 817 times
Last edited by kimeza on Mon Apr 28, 2014 8:10 am, edited 1 time in total.
There was a problem with most every part of this version of the build.
1) as I pulled the cart forward, the left wheel's rotation, turned the washer, which in turn turned the nut which made it tighter. This caused the wheel to lock up stopping the cart.
2) The rotation point (PVC pipe) was not drilled perfectly 90 degrees to the holes for the axle. This caused the front axles to be crooked and misalligned.
3) The rotation point was weak being PVC pipe and was already looking like it was going to break.
4) Pulling the cart causes the front two wheels to rotate in reaction so steering is slow. It kind of "wig wags" side to side behind you on cement. Because of the drag of sand, this is not a problem on the beach.
5) It's still a little hard to pull on the beach. I have to grab the pull handle behind me and lean forward on the sand.
1) wheel to lock up (I just simply installed a nylon lock nut to the left wheel).
Nylock nut solves the wheel lock up problem
0dccfe70-e0af-4e37-9d95-80ff687643b4.png (29.88 KiB) Viewed 803 times
2) The other rotation point (PVC pipe) was drilled on a drill press. I could not drill the two holes with perfect 90 degrees orientation. (I used a wooden block which by the nature of it's shape, allowed me to use a drill press for perfectly alligned 90 degree holes for the rotation point and the axle.)
Stronger that pipe I used in v2.0 Also the axle is 1" behind the rotation point so the wheel turns like a castor when the cart is pulled.
b8924d33-482e-4392-8157-bf820fedd3cb.png (32.6 KiB) Viewed 803 times
3) The rotation point was weak (wood block seems much stronger than the PVC pipe.)
Wood block to mount the 5/8" threaded axle to the rotation point which are a perfect 90 degree angle to each other.
93b9ec99-ce1c-4db5-a002-bfdfe0a625ec.png (39.41 KiB) Viewed 803 times
4) Pulling the cart causes "wig wag". (I don't know of a solution.)
I used this simple steering set up from V1.0. I used the same 3/4" pipe and drilled a horizontal 1/2" hole. Then put that into a 90 degree 1 1/4" elbow. Then drill the elbow with 1/2" hole on one side for the handle and a 5/8" hole on the other side for the threaded bar (rotation point)
4d89b986-3eb7-4f55-9375-88b685ca5bcc.png (39.39 KiB) Viewed 803 times
5) It's still a little hard to pull on the beach. (DUALLY WHEELS!)
The simplest mod was to add the inside dually wheels. Just drill a hole in the axles and throw in a couple of washers for the new wheel and a cotter pin secures it. EASY!
c0636117-d6ee-4ee8-9ead-c736480a74fc.png (29.68 KiB) Viewed 803 times
One side of the dually. Be sure to put washers on both sides of each wheel
217b8ae5-f96d-45bb-9e5f-559a02ad02a4.png (34.64 KiB) Viewed 803 times
Rear view of the dually wheels.
dd825d7c-5f0b-4f04-b876-80b29fac3edd.png (39.98 KiB) Viewed 803 times
After about 10 trips to HD, I'm done! (for now)
39237569-89a2-4185-a6a6-4b8b8d71556e.png (37.04 KiB) Viewed 803 times
Loaded up. 2 kites, 2 boards and gear bag.
9783ec6f-d475-48db-94c3-882b5cf418e4.png (40.93 KiB) Viewed 803 times