The Shelton Plane and Tool Manufacturing was a division of a company that had existed as a maker of picnic baskets under one name or another since 1865, and as the Shelton Basket Company since 1911. Cornelius McAller persuaded Abraham Lavietes, president of the basket company, to finance the manufacture of this plane. This version was the commonly encountered thumblever-on-a-long-screw type adjuster normally associated with Shelton. MacAller died in 1940 but Shelton persevered under Lavietes and later came up with the single-piece enclosed lever cap design. The Stanley knock-offs with Bailey-type adjustments are considered on par with their Stanley-Bailey counterparts. Shelton sold all their plane stuff to Stanley in 1954.
Here the position of the locking screw is turned to the unlock position and the cap can be removed.
Here the locking screw is in the locked position and the cap can be tightened. By turning this screw in and out you can adjust the lever cap.