Newton's Cradle

This is a galery outlining the process of constructing a Newton's Cradle. This was built as part of a physics project and has been featured in an article on Makezine.com.

A video of it working can be watched below. This project was entered in AWC's student showcase event and the presentation document can be downloaded by clicking the Word docx below.

3D Modle

I first modeled the Newton's cradle in Autodesk inventor.

Steel ball bearings

I decided to use 1" steel ball bearings that I ordered off amazon. I then JB welded some metal beads to the top so I can run the string through.

Machining arms

I used 1/2" round stock for the two arms. I machined the 5 grooves on the lathe and did some polishing

Rods done

Grooves

Bending the arms

I used a hosfeld type bender to bend a ~4.5" radius in the bars to form the arms

Setting them up in the mill

After bending the rods, I indicated them in the mill so that I could mill a flat on what will be the bottom.

Flat milled

Both arms ready

After the flats were milled, I drilled some 1/8" holes in the bottom so that I could glue support pins into the bottom.

Base construction

I cut an 8 x 6 x .75" piece of oak to make the base.

Router

I used a router to make a nice looking edge.

Arms mocked up

I set up and measured out the arm positioning.

Indication pins

I made these small pins from 1/8" round tool steel to mark where I needed to drill holes in the wooden base.

Pins in

I just placed the pins in the arms and pressed them onto the base to make indents where the holes needed to be drilled.

Base drilled and stained

I just placed the pins in the arms and pressed them onto the base to make indents where the holes needed to be drilled.

Base and arms ready

Everything is ready to come together now!

Gluing together

I used JB weld to glue the arms onto the base with pins installed for extra support

Finished

I used fishing line to string up the balls. I just wrapped and super glued the fishing line to the arms and then super glued the balls to the line when they were all in line.