On 3 Mar, 14:19, bob wrote:
I am having some trouble fitting a Screfix "Universal Semi Flexible
Disc 115 mm on (Quote No: 18886)" on to a "115mm M14*2.0 Nylon Backing
Pad 22mm Hole" (Quote No: 12966); the locking nut doesn't reach the
thread when the disc is placed between it and the pad. *Am i
assembling this right? *I can see how a thinner aluminium oxide disc
could be pressed down so that it is sandwiched between the two but the
semi flexible disc is not giving much.

Annoying isn't it? offering sympathy rather than advice. I found
exactly the same thing, it needed brute force to get the thread to
take. I think I tried grinding a bit off of the back of the pad to
give a bit more room to play with but don't remember it being a great
success.