Hi Hilde;
First, the needle plate & throat plate are jus two different names for the same plate, which other screw do you need.I have nt measred the throat pate screw on the #8 so off hand do no kno is actual size, may??be a while before I am able to do so.. The Singer thread is not actually a #6-40 it is? 9/64-40. 9/64 = .1406" while a #6 screw = 0.138". They are so close they will often interchange, though depending upon tolerance the Singer screw will not always enter a #6-40 tapped hole.
Miller/TN
