DPH Hardware did make ball bearings at one time; maybe roller skates (mostly sheet-metal parts) too.
There is a picture of their large factory on this site, (somewhere).
Not sure if they had (or needed) capability to forge or stamp chain rings from steel (e.g., boiler plate).
The Nostalgic.net website shows a 1936 "Rollfast" product line catalog with the 5+1 "H" chain ring on "Rollfast" badged bikes and the "star" chain ring on "Peerless" badged bikes. An old "Rollfast" ad from 1939 shows similar, with the words "low price" - so the chain ring was part of the greater "Rollfast" product line, but sometimes
not placed on the top-of-the-line "Rollfast" models, with the ball-bearings badge.
An old ad from the Van Camp hardware stores, described the star chain ring as "fancy pattern" on their "Ben Hur" badged Harris bikes.
Don't mean to split hairs, but sometimes, "Rollfast" may mean different things to different people, in different contexts, (e.g., MW Hawthorne).
It may be kind of like the 1st year Ford Mustangs, yes they were Ford cars, but Ford did not put there name
on them that year, using "Mustang" instead.
DPH may have also been a "
wholesaler".