Here are some factory Frame drawings for Pre Unit Rigid and Swinging Arm Frame models, Tiger Cub models as well as Ariel Single, Twin and the Square Four. Don't think these have ever been published in any manuals unlike the Unit models which can be found in the factory Workshop Manuals. Click on the images for a full size view.
First up is the Tiger Cub T20 and Terrier T15 1954-1956.
Tiger Cub T20 and T20C 1957-1959.
Triumph Swinging Arm Twins 1954-1959 (Do not include 21 and 5T/A models).
Triumph 21 and 5T/A 1958-1960.
1960 Triumph 6T Thunderbird, T110 Tiger, TR6 Trophy and Bonneville TR7 Duplex Frame.
Rigid Ariel Single and Twins 1947-1953.
Spring Frame Ariel Single and Twins 1947-1953.
1954-1959 Ariel Single and Twin Swinging Arm Frame.
Ariel Square Four 1947-1959.
Hope this information is useful to fellow Triumph and Ariel enthusiasts. Originally published in Johnson Motors Triumph/Ariel Dealers Meeting Notes, January 1960.