And it won't... The Yor-Lok is an adapter. It goes from 1/2" steel tube to a female 3/8th in. NPT. The -8 aluminum fitting is an adapter also with a male 3/8th NPT that threads into the Yor-Lok.
The Yor_lok adapter I am using is this one.
McMaster-Carr

The -8 aluminum adapter I am using is this one:
Earl's AT981608 Earl's Ano-Tuff Adapter Fittings

Mark