Patented & Distinctive Bit Braces
A Research Study
by George Langford, Sc.D.
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Unpatented Spofford's Pat. brace

This well made brace is laid out exactly like the early malleable-iron frame Spofford braces made by John S. Fray, but the split-frame chuck is adjusted by a sleeve engaging a threaded member embedded in the frame instead of by the usual thumbscrew. This brace's maker's mark: John S. Fray & Co. mark: Nelson Spofford's March 23, 1880 patent covers the method of coring the split in the making of the original casting and would indeed apply to the present brace. In the bottom image on the left, this brace (on the top) is compared with a regular Spofford brace made by John S. Fray & Co. (below). The two wrist handles are nearly exactly the same size & shape, but with differing widths of their cast-in-place pewter rings (see another Fray brace here) but the present brace's casting shape is better integrated with the shape of the handle than are the Fray-made brace's frames. This brace's key concept is the combination of the paired inclined planes in the floating threaded block that engage ramps inside the rectangular-outline holes in the jaws, along with the conical surfaces on the outer ends of the jaws that are engaged by the conical interior of the threaded shell, that together squeeze the jaws flexibly against the tapered square tang of the bit. There is no corresponding patent by Nelson Spofford for the closing of a split-frame chuck with a sleeve like the present brace, and there is no such patent in Pearson's compendium of brace patents, but there are a number of patents involving the split-frame concept: 25,984 - Spofford 59,254 - Orbeton 204,416 - Backus 205,400 - Knowles 210,335 - Knowles 225,768 - Spofford 254,275 - Chantrell 270,072 - Ives 301,058 - Ives Spofford's #225,768 patent is the one that applies to the method of coring the frame split, and Knowles #210,335 patent comes close with two years earlier prior art with which the present brace might have interfered.