Bending metal is part of building a robot, a gripper/claw/clamp/hand arm, or general motor or servo control. Something has to hold the motor in place, and somehow you have to keep that servo from moving. Metal cut and bent to fit the job is what is needed. What about joints and levers? To get a clamp to function it needs to connect to a servo or motor. Formed metal is a great way to make a linkage.
In the bottom of the photo is a hand gripper. You squeeze the unseen handle which pulls a string which pulls the bottom of the gripper part, making the yellow lever pull against the nonmoving arm.. I made a servo version that has three joints so it can grip, move left/right and up/down.
Look at all the sheet metal I had to cut form and bend! So where did the metal come from? What did I need to fabricate it?
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Step 1: Raw Material and Tools
I used common (and cheap) formed metal. The skinny piece is a angle trim that holds ceiling tile to a wall It's about 3/4 inch per side. The piece above it is the coner molding for dry wall mudding. And the big piece is a metal wall stud. All these pieces of metal is formed already, so I had to cut the piece then hammer it flat on cement so it becomes a piece of sheet metal.
Tools needed is a marker, hammer, and sheet metal cutter or tin snips.
Cut the molding bigger than you need. Bend with plyers any rounded edges (like on the stud), then lay on cement and hammer flat. Make your marks of where you want to make your cut then cut. use a small square so your lines are true.
Step 2: Brackets and Holders for Servos and Motors
I can't tell you how to design your bracket or holder, this is for each of you. Everybody will do it as your project needs to be cut. Your needs will force you to cut the metal to shape, how and where to bend it, where to drill holes. and do whatever needs to be done to get your formed piece to work.
Your cuts and especilly your bends have to be square or your finished piece will be out of square. On most parts this isn't critical, but you will find out that on some pieces it has to line up with the previous piece or the next one. If you make a mistake, just unbend and hammer it flat again.
Here a bracket is being formed. Make your line, bend it by starting with the line on the edge of your table, hold with your fingers on top and your thumbs on the bottom and push.
Look at some finished pieces. It isn't that hard to make the cuts, it's knowing where to cut and where to bend.
Step 3: Views of Finished Remote Controlled Gripper
Look at these photos. See how many levers there are? To move the clamp I had to extend the servo arm, Comming off of it is a connecting linkage, comming off of it is another, then the gripper itself. The gripper as one moving part, the "L" shaped piece. Since all these parts pivot, the connecting bolts must be kinda loose so there is no binding. And the servo arm extension has to be level with the linkages and levers at the piece you want to move. You will figure this out for yourself as you construct your device.
Hinges and such will need long--two or three inches long-- skinny bolts. I call a bolt anything that needs a nut screwed to it. Your joints will need some. Look at the finished gripper. You will see the joints have a bolt holding it together and one side of the joint is firmly attached to another part.
Step 4: More....
You will have to make some bad pieces before you finnally get everything right. Metal is sharp so be careful. Take your time. Measure twice, verify, then cut. Make your marks, then bend. Sometimes I did it all on cardboard cut from a ceral box to see if I was doing it right. Start simple. Make servo brackets first then try something more complicated.
After cutting the first two cuts for a servo bracket you will scratch your head wondering how to get that inside cut done. I would bend the metal one way so I could get my snips in place, cut it, then bend the metal back and hammer if needed. This is a trial and error experience. Be easy on yourself. Mistakes will happen. In the end you will get the job done. It might look like crap but it works, right? Your next creation you make will be better than the first one because you now have some experience cutting, shaping, bending, drilling metal. Rebuild your device or start another. Each time it will function better and look better. It won't be long untill you have a working robot that can move like a machine is supposed to.