Balls won't load. Please help.

[takethecastle57]

and biscuits

[Kbarrow]

Just wanted to ask one more time before I cut the plastic.

Does anyone know why the "bubble" piece is blocking the other plastic piece that I need to screw down? I've tried every which way to try and force it in there but I'm scared to break a piece of almost 50 year old plastic.

Thank you.

I have a picture in post #20 showing where the problem is.

[sparky kilowatt]

Just wanted to ask one more time before I cut the plastic.

Does anyone know why the "bubble" piece is blocking the other plastic piece that I need to screw down? I've tried every which way to try and force it in there but I'm scared to break a piece of almost 50 year old plastic.

Thank you.

I have a picture in post #20 showing where the problem is.

No idea why it's not clearing the ball feed mechanism, I've checked two of my machines, can't see anything that would cause the clear window to cause interference.