[s-cars] Turbonetics hose clamp specs (lock nuts)

[TM]

I'm hoping that others on the list are using these hose clamps
for their Samco hoses.

That said, what is the specification of the locknuts that are used
for these clamps?

One of my clamps is missing a locknut and when I got ambitious and
went to install the lower intercooler hose, I found that the locknuts
I bought were the wrong thread pitch. I bought 1/4"-20 stainless nylock
lock nuts. These appeared to be close in pitch, but they are wrong- only
one revolution and the threads don't work.

Are these some sort of metric pitch or something very unusual that
I can't get at the local hardware store? Forget about the autoparts
store,
they don't have anything remotely close.

Tom at Euro-Car is trying to find me a locknut, but I'd like the spec so
I know what I need to buy.

Thanks.

Is there such a thing as a thread pitch scale for a nut?

Taka