I wanted a rowing machine but didn't want to pay the $1000 or more or for a gym membership so I built one. There are homemade rowing machines on the internet and here on Instructables but I decided to create my own version because, well, I don't follow instructions very well...
Oh, and it sort of folds.
This involves welding but you could probably do it in wood if you are creative and most of the measurements aren't set in stone. You could alter them to suit you.
Total cost for this project? $0, since I already had the materials. I have no idea what it would cost to buy the materials but it would still be very cheap.
Time for the project? Probably about twenty hours but at least half of that was trying to figure out how to build it.
Materials: Wood, angle iron, rollerblade wheels, bolts, screws, bike chain, handlebars, 26" (56cm) bike wheel, material for vanes, vegetable oil, rear bike dérailleurs, bungee cords or inner tube, bike axle, miscellaneous hardware.
I didn't take any pictures while building it but hopefully you'll get the idea from the pictures that there are.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: The Frame
The wood I used for this are some 2x3's (finished 1.5" x 2.5" - 3.75 cm x 6.25 cm) I had laying around. You could use 2x4's or whatever you like but make sure it is strong enough. You don't want the wheel to break off and smash you in the face because you didn't make it strong enough!
The main horizontal wooden supports the metal rails sit on are about 50" (112 cm) long and there four 8.5" (21.5 cm) spacers. Two spacers sit at each end, the centre of the third spacer is 18" (45.7 cm) from the front (so the metal rail can be screwed to it) and the centre of the other spacer is 16" (40.5 cm) from the back. The spacers separate the horizontal supports and strengthen it.
Four feet 12" (30.5 cm) are attached to the bottom at either end of the horizontal supports. These raise the frame up enough so the drive mechanism doesn't hit the floor and can also get around the spacers. Since I didn't have screws long enough to go through the the feet directly into the frame they are attached by screwing the feet into another piece of wood and that wood is screwed onto the frame.
There are two uprights (12.5" - 32cm at the longest point and cut at a 45 degree angle) at one end at the front on either side. They hold the wheel frame up and are braced against the frame. The braces are about 9" (23 cm) long at the longest point and have 45 degree cuts on each end.
Step 2: The Wheel Frame
The wheel frame folds down reducing the size of the rowing machine so it can be stored a little easier.
The main wheel frame supports are 24" (61 cm) long and is attached to the main frame by two hinges. I used door hinges because that is what I had but you could use other types as long as they are strong.
There are two wheel frame spacers 5.5" (13.5 cm) long. One is placed at the base of the wheel frame and the hinges are attached to it. The centre of the other spacer is placed about 12" (30.5 cm) up (which is the middle) but if you want to put a tire on the wheel then it will have to be placed lower, probably around 10" (25.25 cm). I'm thinking of doing this so I can attach a blender, generator, or washing machine at some point in the future.
Two holes are drilled through the uprights and the wheel frame to slide bolts through at will hold the wheel frame up while in use. The bolts are 5.5" (13.5 cm) long since they are what I had but you could use shorter ones.
Step 3: Metal Rails
The metal rails are angle iron about 35" (80 cm) long and there are tabs welded on to them so that they sit in a vee configuration. This is so that only four wheels instead of six are needed to guide the seat.
The rails are screwed into the frame at the back end and into the frame and frame spacer at the front. The placement of the frame spacer depends on where the rails screw into.
The centre of the rails are 7.5" (19 cm) apart and the wheels ride in these.
The ends of the rails have stops so the seat doesn't leave the tracks.
Step 4: Seat
The seat is just some scrap pieces I threw together and most likely you can do a better job. After these pictures were taken I added foam to the seat because I have a delicate bum.
The angle iron brackets are 2" (5 cm) long and on one side are two hole for screws. The other side has a hole for the rollerblade axle and it is 1" (2.5 cm) from the ends and .75" (2cm) down from the narrow edge. The spacing between the brackets is 4.75" (12 cm) but you could make it a longer longer if you want it a little more stable. Just make sure you still have full range of motion for your legs.
There are washers as spacers between the rollerblade wheels and the brackets because without them the wheels would rub.
Step 5: Wheel
The wheel is a rear 26" (56 cm) bike wheel and the vanes are some flexible plastic pipe I had. They're cut to fit in the spokes and zip tied in. The vanes add resistance and blow air at you when you're working out. That is definitely a bonus!
Step 6: Handle
The handle is just bike handlebars with a tab welded on to hold a hook and the chain. There is a holder to place the handles screwed into the middle wheel frame spacer.
Step 7: Foot Straps
If you had noticed in the video that I didn't have any straps for my feet. I added them later and they're just nylon straps and buckles (like what you would find on backpacks) and I nailed them into the frame.
My feet sit on the main frame and the wheel frame so it helps the wheel frame from being stressed so much, not that I'm afraid it will break.
Step 8: Drive Mechanism
The chain is about 105" (277 cm) long. You may have to join more than one chain together to get the required length. One end of the chain is attached to the hook by the handlebars and the other end is screwed to the back of the front frame spacer.
The chains I had were rusted so I soaked them in vegetable oil. The oil doesn't harm the environment which is awesome. and I also used vegetable oil when drilling the holes in metal.
To run the chain around the front I welded a derailleur to a piece of angle iron and attached it to the front spacer. Make sure you have enough space between the ground and the bottom of the frame.
The second derailleur only has one wheel and the other end is attached to bungee cords. If you watch the video you can see the derailleur moving back and forth under the frame.
The bungee cords move around an axle attached to the back frame spacer and hook into a bracket in one of the middle spacers. To get full movement the bungees should move around an axle and a middle wheel is needed for the chain. If you don't have these then your chain will be too long and it won't work properly unless you make the frame much longer.
If the chain and middle derailleur hit the spacers then just cut out a notch wherever needed and it should be good.
Step 9: Enjoy!
It's quite the workout using this machine. You can change the difficulty by adding or taking away bungee cords.
You can also change the design of the machine if you like! I'm sure you could make a better one. Just search the internet for homemade rowing machines. There are a lot out there.
Have fun and enjoy!