One does not wish to have one's servants tire from hand carrying a filled multi-gallon garden sprayer to tend the many acres of roses on one's estate. Build a cart that will roll the sprayer, and the servants will still be fresh at the end of the day so you can work them well into the night. Most parts can be found in scrap bin. To see my related Instructables, click on "unclesam" just below the title above or in the INFO box to the right. On the new page that appears, repeatedly click "NEXT" to see all of them.
Unclesam

Step 1: Bottle Removed

Main chassis is 2X4 12" long. Upper wood adapter is 1-1/2" by 1-1/2" by 9-1/2" long, corners rounded. Wooden towing rod is 3/4" dia by 15" long, chosen because crutch tip just happened to fit tightly onto it. Metal uprights are electrical conduit that measures about 5/8" outside diameter, 24" long each. Foot is the same material, 9" long. Rubber tape is wrapped around the end of the foot to make it big enough to grip crutch tip. Two 10" lengths of water pipe insulation are taped around the metal uprights.

Step 2: Bend Metal Uprights and Foot

Metal uprights are bent beginning 16" from their lower ends using tubing bender common in electrical work. Foot needs to be given bend before it is cut from longer stock.

Step 3: Drill Wood Parts

Using flat-blade bits, drill holes in wood parts to receive metal uprights, towing handle and lag bolts that hold wheels. A much neater result is achieved if the shallow holes are not drilled all the way through the wood, but drilling holes all the way through using common drill bits will still make a usable caddy.
The spacing between the centers of the holes for the metal uprights is 7" and their centers are 1-1/4" from the edge of the 2X4. The centers of the holes for the wheel axles (lag bolts) are 1" from the opposite edge of the 2X4. The hole for the foot is centered both ways on the edge of the 2X4 nearest the holes for the wheel axles.

Step 4: Wheels and Axles

I chose 8" dia plastic lawnmower wheels, a washer on each side of each wheel. Axles are lag bolts that have an unthreaded portion near their heads that fits the wheels (typically 1/2" diameter), and long enough so that the wheel does not run on the threads. The bolts' threaded part runs several inches into the wood. Since the bolts are run into endgrain, holes for the lag bolt threads should be drilled as deep as the entire length of the threads to prevent splitting, and if any of the unthreaded bolt will enter the wood, the holes should be enlarged just to the depth that the unthreaded portion will penetrate.
Note in this photo that once metal or wood rods are in their holes in the wood parts, a hole is cross-drilled into the wood and into the rod, then the hole countersunk for the head of a locking drywall or decking screw.

Step 5: Wood Adapter

Tops of metal uprights and end of wood tow rod fastened with screws.
Add crutch tips and pipe insulation, attach sprayer bottle using bungee cord. The bungee cords available from my local purveyers were either too long or too short. I had my man have a custom one overnighted from my usual supplier of custom cut cordage (whenever I need a specific length of a particular string or ribbon) located in Berlin, a company named Ich Bien Ein Bungee.
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