This is a heavy duty cart that will be great for moving concrete, rocks, gravel, bags of material, buckets of drywall joint compound. At 24 inches wide it could even go through a doorway if needed.
2x4 lumber...I got some of mine from store once I ran out of leftovers from concrete forms.
either 4 or 6 Pnumatic wheels. Most of mine came from garbage or cheap at harbor freight
lots of good wood screws
At few 5/8 bolts and lock nuts and washers
A 4 inch long 1/2 bolt and some fender washers and a lock nut
A few nylon washers that o.d. Fit 1/2 bolt. 2 washers should be larger fender washers and one smaller. See step 3.
Step 1: Frame
I have always been a fan of semi trucks and dump trucks so I conceptually designed my hand cart thr same. This does allow more weight than a standard 4 wheel cart but does create sideways friction when turning, especially sharp turns.
The rear wheels are just 2x4 vertical towers and then blocking style bracing. There isn't any super complicated engineering. Just get the horizontal load vertical to the wheels. I didn't use any, but triangle bracing would probably be a good upgrade. This works fine. (see final step)
Step 2: Wheels
Step 3: Steering Mechanism
Ackerman steering uses a series of tie rods and control rods that makes for a lot of different moving parts. More parts equals more expense and I wanted cheap.
My imagination told me a bearing lime a lazy Susan or the swivel on a swivel caster would work fine but I couldn't find one that was going to fit on a 2x4.
Finally it came down to a simple king pin design. I used a half inch bolt that runs vertically through the front of the cart. Instead of ball bearings I opted for simple nylon washers lubricated with oil to keep friction down. I used three washers, a big one, a small one and a big one as a kind of sandwich. I figured the big ones at the top would hold tight to the wood and spin aginst the small one.
This does work well. I used it several times already and it spins great even with a lot of weight on it.
Honest review...Metal washers would probably work just as well. Wood on wood will create a ton of friction but metal on metal will probably be fine. Or a metal and nylon combo. Sandwich two big metal fender washers around one nylon washer. That would be a good and cheaper option.
Step 4: Attach Steering to Frame
The front axle frame is just some 2x4 boxing. L frames help to create 2 direction strength. To keep the axle from sliding I used some cheap hose clamps.
The pull handle is attached with a gate hinge to allow vertical swing. I originally used a pine 2x2 bit it cracked under heavy load so it will be replaced with steel. A good hickory shovel handle would probably work much better than what I used. I will be replacing it with 16 gauge square steel tubing bolted to the hinge. The pull handle is shorter than the entire frame so it can be stored under the frame.
Step 5: Load Test
So I got a crow bar under it to lift it about 2 inches. Insert 2x4. Use bar on another board to lift a couple more inches. Repeat until I can get my automotive jack under it. Jack it up and insert jack stand. Repeat until all 4 corners are supported by Jack stands.
Now is the fun part... Roll cart under slab. Jack up one side remove stands. Same for other side. Bam 700 pounds of concrete slab on my little cart. Will it move???
YES. It actually rolled well. The pnumatic wheels are rated at 300 pounds a peice. In theory I can put 1800 pounds on the cart but I doubt the wood frame will handle it or even the wheels are actually that tough.
Sorry I didn't stop to take many photos during the actual move. Between excitement and physical work I just kept rolling(pun intended). Trust me this wagon hauls lol. I am impressed.
I have also used it to move a couple large metal cabinets with stainless steel counters(salvaged from a restaurant remodel) around myb) back yard that are becoming a summer canning kitchen. They only weighed a couple hundred pounds and the wagon preformed flawlessly.
I only had a few difficulies. One the weak 2x2 I was using as a handle cracked. I used a heavy C clamp to hold it together to finish what I needed but this will probably be replaced with steel tubing.
Second two tires began leaking air and caused it to want to skew off direction and not roll well with flat tires. The used tires will need some fresh tubes. No big deal. I just used my air bubble keep filling up the flats.
I made it and got it off the same way it went on. Goes to show simple tools can move huge loads easily. No need for heavy equipment.