All of our handles ship with the appropriate replacement hardware. But we do sell quite a few hardware sets separately, which customers use to replace older hardware that no longer works. A common issue with the older hardware is that the slotted screw heads strip.
With regard to determining which size hardware set was required, a customer recently asked:
When I remove the existing one and screw it together and measure the length I get 1/2 inch. Will this be the right size or too long?
We sell two hardware sets, the one for small handles, and the one for all the rest (medium, large, x-large). The small handles fit very very few Revere Ware pieces, so the likelihood of needing the small hardware set, which is made specifically for those small handles, is slim. So, a default choice would be the M/L/XL hardware set.
But, if you need the measurements, here they are.
The hardware set comes with two different length barrel nuts. The short of the two, with the screw all the way down, measures about .46 in between the inside of the barrel nut head, and the head of the screw. The longer one .61. The washer makes them a little bit smaller. Typically, the front and back of the Revere Ware handles will need different nuts; the front a shorter one, the back a longer one.