These axle plates are the same ones that David Bird uses on his weld-on hardtails for Triumph oil-in-frame bikes (1971 & up). They are set up to use stock OIF Triumph axle (5/8") and axle adjusters. You can use them for that custom hardtail you want to build, they will work seamlessly with 1-1/4" tubing which matches up with your stock front frame section.