There's an easier way to experiment with kettlebell swings for only $11. You may have read about the T-handle in the Timothy Ferriss Four-Hour Body book, or maybe you learned about it from a frugal strongman at your local gym. Either way, putting together a T-handle is quick and easy and customizable for your weight-training needs.
I know that Instructables has some great guides for building kettlebells from concrete and inexpensive rubber balls ($10 DIY Kettle Bell and DIY Kettlebells for under $10, two alternatives to this project with two different techniques for putting a handle on some weight.) But I am not going to mix concrete, bake some PVC, learn to weld, or sacrifice my balls just to make a kettlebell that I might not use more than a few times. But I have $11 and access to some rusty old mismatched weights in the basement of my apartment building. So let's start the swinging party.
Step 1: Parts List
The main vertical bar
One 3/4" by 12" steel nipple
Two 3/4" by 5" steel nipples
One 3/4" steel T-joint
Tape (so your hands don't get destroyed by the threading on the pipes) OR
Gloves (so your hands don't get destroyed by the threading on the pipes)
One 3/4" steel floor flange
You can use galvanized steel if you're fancy, but I went for inexpensively hardcore with black steel. All told, $11. For me, the floor flange was the most expensive component at $4.50 from Ace hardware. The T-joint and the five-inch nipples each cost about $2. (Compare that to buying several different-sized kettlebells at around $60 a pop.)
I already had some tape on hand, but if I were to do this again I'd throw on some of that rubber handle-coating stuff that they sell to restore damaged tools. Plastidip. I would also use something to keep the bottom from flying off. Not that it did, but after doing some swings in a room filled with giant mirrors and a sliding glass door and cabinets full of fine china*, I got to thinking that maybe I should do this someplace with cinderblock walls rather than inside of my apartment.
Given how this device is to be used (repeatedly heaving it into the air), I recommend using a wrench to really tighten that floor flange. Seriously. Maybe use some Loctite or JB Weld. Something that will keep your weights from flying off the handle. Also, use it someplace where nobody is standing directly in front of you. And where the floor is sturdy. If you're a member at a grimy boxing gym with brick walls and a plywood-covered concrete floor, that'd be perfect. I make no promises that you won't get kicked out of a 24 Hour Fitness for using this.
*I don't actually have any fine china. But I do have a television that I quite like, so no more kettlebell swings in the house.
Step 2: The Assembly
Screw the T-joint onto the other end of the 12" nipple. Then screw in your 5" nipples to either side of the T-joint. DO NOT OVER-TIGHTEN this part. I know you got pretty into the tightening process in the previous step, but ease up this time. You will be removing the handle in order to add weights to your T-handle.
Wrap your handles with tape. You could use athletic tape, electrical tape, duct tape, bicycle handlebar tape, even packing tape. Scotch tape and masking tape are not recommended, as they come off with moisture. And you will be sweating all over these handles in no time at all. Use something waterproof.
To keep the weights from banging into one another and making a godawful racket, have a clip on hand to hold the weights in place. (If anyone knows of a good, round, small-diameter clamp to hold this in place more securely, link to it in the comments. I spent a while searching online for a pipe fitting that would close over the weights to hold them in place, but I came up empty.)
Step 3: Add Some Weights
When you get good, you can add more weight. I like to adjust mine to the point where I can just barely manage 50 repetitions. (I learned the hard way to use several smaller weights rather than one large-diameter weight. Your knees will appreciate not having large iron discs crashing into them.)