I'm amazed at how a simple thing can baffle me. I need to repair one of the lines holding the ball in Newtons cradle. It looked like I was just going to pull out the line that was threaded through the top of the ball and replace it. Easy! When I had a closer look it seems the hole through the ball is sealed with something. Does anyone know how I should fix this? Once I clear the hole, do I need to reseal it so the ball won't slide along the line? Looks like it was originally attached with fishing line.
All I have used have little ring on top that you tie string to then the sides have to be the right length so that the ball stricks next ball right on centre vertically as well as longitutely (is that a word?) your one sounds good just get the hight right then apply some clear nail polish to string then centralise, also would be good idea to dab some polish over knots on the frame to stop little fingers tampering with it once you have fixed it
I need to repair one of the lines holding the ball in Newtons cradle. It looked like I was just going to pull out the line that was threaded through the top of the ball and replace it. Easy! When I had a closer look it seems the hole through the ball is sealed with something. Does anyone know how I should fix this? Once I clear the hole, do I need to reseal it so the ball won't slide along the line? Looks like it was originally attached with fishing line. 
When I get the hole cleared I'll certainly dob some on to stop any sliding around. 