Intro: Wooden Robotic Hexapod
Answering the question that probably came to your mind when you first saw this instructable: yes, this robot is completely made of wood, glue, and a motor (I ran out of time to add the motor, but I will add it). When I first thought of this idea, I thought there was little hope of bringing it about. Then after a little while I sat down and designed it (the link to the initial design is down below), and realized that building a six legged robot to life could very easily be brought about. The resulting robot simply walks in a straight line, but it has six legs and showing this baby off to friends will make you feel really cool. This robot utilizes a number of mechanisms that could be very useful on other builds, and is a learning experience that teaches how to use simple applied mathematics, mechanics, and woodworking in a standard small project. This little robot is probably the coolest thing I have ever made, and I hope everyone else finds it just as fun as I did. Also, i will say what most things are for, so if you have an idea f how to do it better, feel free to leave a comment.
As I mentioned in my last instructable, I have access to a fairly nice wood shop which is what I used for this project, but do not be afraid, you can still build this robot with hand tools. Just be a little more careful, or you could end up with some very non-precise pieces.
3d model: http://www.123dapp.com/AssetManager/Publisher?stgAction=getProduct&intProductId=665285
WARNING: there are some dangerous tools used in this project such as a drill press(particularly with the ¾” bit) and the saws. Have caution with these as they are dangerous when misused.
Drill- I used a drill press, but you can use a hand drill, you just have to be very careful with the ¾”.
Drill bits- 3/8”, 1/2", ¾”, 1"
Saw- I use a combination of power saw and hand saw.
Vices- many clamps, and one anchored vice
-125 inches of ½” dowel (not necessarily in one piece)
-48 inches of 3/8” dowel
-Some 3/16” plywood or other thin-ish wood
-some wood about 1/2" thick
Motor- preferably with some good torque
4 sprockets- link here https://www.instructables.com/id/simple-wooden-sprocket-without-cnc-machines/
Step 1: Basic Hinge Modules
First, note that this instructable has a number of things repeated 6-12 times, this being one of those steps.
Start by cutting strips of the thin wood so that one strip is ½” wide and the other is ½ + 2W(width of the wood). These strips will form hinge casings for later steps. Once the strips are cut out, you can cut the skinny strips to 12 one inch long strips, and the fat ones to 12 two inch long strips. After they are cut, you can assemble and glue together the modules. Refer to the above pictures to do so. Remember the goal is to get the inner dimensions to ½”x ½”.
Step 2: Hinge Module (cont.)
Now cut 6 pieces slightly under 2” from the ½” dowel. Glue these pieces in the back end of the hinge module as shown, as to leave one inch sticking out. Drill a hole with the 3/16”, in the center and 3/8” back from the edge. Then drill a hole 3/8 “ from the back end of the dowel, in the center. You will need to cut off the corners of the original hinge module as shown above, so that the leg module will run smoothly.
Step 3: Hinge Module Holder
Take your thinner wood, and cut out six 5" squares. Then drill a hole in the center, and in one corner, 3/4" from both sides. these will spin holding the part from the last two steps.
Step 4: Middle Hinge
Cut a 1.5" length of 1/2" dowel. Then drill, using the 3/16" bit, 3/8" from either side, but make sure the holes are as close to 90 degrees different from each other so that the hinge works properly. This is the piece that will connect two hinges so that in the end, they will have 2 dimensional freedom.
Step 5: Hinge to Leg Modules
From the 1/2" dowel, cut twelve 8" long pieces, then drill a hole in each one, 3/8" from the end. Now, from the 3/16" dowel, cut six 7/8"
pieces and six 1.5" pieces. Glue the 8"x1/2" dowel pieces on either side of the module from the last step, glue to the 1.5" dowel, not to the actual module. The small piece should move independently of the others.
Step 6: Finishing Leg Hinge Module
Use the 7/8" small dowels made in the last step to glue in the module from the second step to the part made in the last step. This part must be free spinning so be careful with the glue. Now cut six 1" pieces from the 3/8 "dowel, insert the large hinge module into the module holder, and glue the dowel into the hole in the back of the hinge.
Step 7: Axles
Now cut three 7" long 1/2" dowels and drill with the 3/8" bit 2" from each end. Cut 6 more 1" pieces of the 3/16" dowel. Stick the sprockets(don't glue) on, and glue in the small dowels into the holes in the larger dowel. These two small dowels will keep the axel from dislodging or catching on the back of the leg module.
Step 8: Chassis
Now you will need to make two pairs of boards. The first, with 4 1/2" holes spaced 6", and the second with one half inch hole then every 6 inches, space out 1/2" and drill two 1" holes, and repeat this until you have seven holes on this board as shown above. This board will act as the fulcrum for lifting the robot.
Step 9: Spacers
Now cut four pieces of wood that are 3.5" long and glue them on as shown, after inserting the axles. these will space out the chassis.
Step 10: Leg Module Hookup
Glue the leg modules onto the axles 3/8" from the end, but make sure that the two on each axle are exactly opposite each other in orientation as shown. In this way, when one leg is up, its counterpart on the other side is down. this is what will facilitate the walking motion.
Step 11: More Spacers
Cut thinner pieces of wood 3.5" long. these will end up spacing the fulcrum(board with seven holes from step 8) from the rest of the robot. check to make sure that these don't get in the way.
Step 12: Legs
These don't have to be incredibly precise, so i just cut some wood that looked right, and drilled two 1/2" holes spaced 1" center to center, and 1" from the top.
Step 13: Finished (not Quite)
now just assemble the last few parts by sliding on the board with 7 holes from step 8 lining up the leg modules and gluing in the second spacers. then glue on the legs, and you have a finished product. This still needs a drive belt and motor, and i will get those to you shortly.
Hope you had fun!