archimedes screw
 

Hello

I am helping a FTC team with an archimedes screw design to lift a 3 inch diameter ball. Does anybody know how to design the spiral patter to cut it out of sheet metal.

Thanks

Re: archimedes screw
 

cut multiple doughnut shaped pieces and make a slit along its radius. connect the pieces together with fastener of your choice. Picture a slinky with a slit down one side. The resulting pieces are what you have to make

Re: archimedes screw
 

I would highly recommend starting with cardboard to get practice and test it out first - we took a serious look at it last year for Lunacy, before finally giving up on it as being way to intensive to build for the team.

Re: archimedes screw
 

+1

+1

Think about putting the doughnuts around a pipe with some simple angle brackets.

Re: archimedes screw
 

The disk method is the way to do it and prototyping with card stock so you understand the process is a must. Start with a few disks the diameter you need; the diameter of the balls X2 + the diameter of the support pole + 1/2 inch for a fudge factor. Assuming 3 inch balls and a 1/2 inch support pole, a series of 6 1/2 to 7 inch disks will just about do the job.

Make the holes in the centers of the disks the diameter of the support pole. When you cut the holes in the centers you might want to leave a little material to make attachment tabs. I recommend making a series of slits frin the center to the pole diameter size.

Make a cut from the center of the inner hole straight to the outer edge. This is where you'll attach the disks to one another.

Stack the disks with the slots aligned and take the left slot edge of the top one and tape it to the right slot edge of #2. Then the left of #2 to the right of #3 and so on.

Good luck!

Re: archimedes screw
 

One of my favorite methods for making a spiral was to bend two pipes into a spiral, and use them as tracks for the ball to roll on. You'll probably find that it's a bit easier to make than trying to find an approximation of a shape that can't actually be flattened.

Re: archimedes screw
 

Heres an example of the "donut" method, used in one of my architecture projects. I really think its the easiest spiral to make/understand.