Improved plunger spring somewhat by cutting the low-gauge (thick) spring, and using it along with some high-gauge (thin) spring. We can’t put two thin springs together because the thin ones do not have well-finished flats.
To cut the heavy-gauge spring, I mounted our vise and used the Dremel.
The plunger spring situation is still not quite right.
Replaced temporary plunger screws with original ones.
Status changed: Broken → Good
Replaced plunger spring with one made from thicker wire that has the same compression distance. The machine launches balls now, but not quite properly , a slightly longer spring is needed.
Ordered a stronger spring from McMaster-Carr
Plunger spring needs to compress entirely into socket, which has about 3/4 inch of depth. I will look for stronger springs that conform to that
Old spring appears to be 23/64 inches in outer diameter. We need a thicker or maybe longer spring
Washer solution failed. The compressed spring must fit INSIDE the plunger frame.
Attempted constructing a smaller washer by filing down and heating a plastic washer but it merely got stuck. We need to order real springs. I looked this up and will make parts requests for a couple possibilities