I made ones similar to those for my own eq use. I would not make them for someone else.
I took some automobile front disc brake pads that still had lots of the pad still on the metal backing and used a metal cutter and cut off the size I needed from the auto brake pads and then drilled a hole through the pad and metal backing, then drilled the pad side larger in diameter so as a pan head brass screw of about 8/32 size would be countersunk in the pad and bradded the back side screw threads to hold the nut in place. I was not restricted in the amount of retraction and en-gauge space for the thickness of the pad and it's backing.
These pads were old ones from my junk pile salvage, but you can buy a front set new front disc auto brank pads for around $10-15 if you go back to vec's in the 80's or maybe 90's.
If you know a mechanic or brake place you can probably find good discarded ones. their is no core charge for such so they junk throw them in the scrap pile.
Be aware that you need to wear a good respirator and gloves when cutting the metal and pads due to the dust involved.
I made several at once, just as easy to make half dozen as to make one.
I could have used pop rivets but already had several of the pan head brass screws.
I did this couple years ago when I seen those inflated prices and prices of mower OEM replacement pads has gone up more lately.