Given that the cutters in the O.P. were marked U.S.Prop .I got wondering if they might have been used on special machinery for machining aircraft propellers .
This modern creation uses a narrow saw to profile a relatively small propeller .
This older machine looks like it may have a wider cutter on it but it's hard to tell for sure.
progress-is-fine.blogspot.com
This type of machine has been around for a long time so perhaps some used wider cutters on larger props for roughing operations .
Title varies: 1905-June 1960, Canadian machinery and manufacturing news
archive.org
I didn't find any of these machines on Vintage machinery but you can see some of the other similar type machines built by Mattison here ,
and the tooling they made here
Wisconsin Knife is one company I am familiar with that still supply this type of corrugated knife stock in high speed steel and still have some similar brazed carbide knives , see Page 40 for the Carbide knives and Page 57 for the cutter heads .
Most cutter heads have more than 2 blades
The wider cutters in the OP might also have been used on a wood shaper of some kind that when stacked together may have been used to clean up the outside of the propeller hubs .
Perhaps there will be more information on prop making in other volumes of Areal Age or similar magazines
I'm not sure if U.S. Prop made similar forged aluminum props or how they were machined .
Butterfield / Union Twist Drill in Derby Line VT/ Rock Island Quebec also made the inserted tooth milling cutters similar to the G&G ones shown in John Oder's post.
Jim
P.S. I've added some pictures from my Butterfield Catalogue #29 that dates from 1959