Bodkins are quite frequently mis-labeled as Fids on eBay.  Here are definitive differences.

Fids are usually 5-inches to 12-inches long, conical in shape from a sharp point to a 1-inch to 1.5-inch wide, rounded end, hand-carved or lathe-turned hardwood or whalebone. Decorative fids of assembled ivory sections or mixed wood & ivory, are also to be found. Fids are used by sailors of all ship types, to loosen tight knots and to splay the end of hemp or nylon lines (rope) prior to splicing two lengths together to make a single, longer line. Whalebone is distinguished by dense weight & vascular grain.

Image #1 is a whalebone fid of 13-inches & 12.4-ounces.  Image #2 is a 7-inch, 3-section decorative bone fid with a carved fist top section, with the mid section lathe-turned in the style of a Narwhal tusk.  Image #3 is a 5-inch fid with a point of bone and a handle of ivory.  Image #4 is a bone fid of unknown matrix.  Image #5 is knob-topped whalebone fid.

Bodkins are usually 2.5- to 3.5-inches long, conical in shape, hand-carved or lathe-turned whalebone or ivory implements, used specifically for tatting lace doilies. Making & selling doilies was a very important income source for Nantucket womenfolk while their men were on whaling cruises that lasted up to four years. Whalers only made bodkins for their mothers, wives, sweethearts, and daughters. Whalers never sold bodkins, as this would contribute to potential competition for the Nantucket women. Authentic bodkins were made with no eyes; the multi-twist lacing thread was tied to the narrow waist of each bodkin. Eight bodkins were needed to make an eight-sided doilie (also doily); six were needed for six-sided. Bodkins were made in several sets of matched pairs, set opposite each other to keep distinction between the matching wedge patterns of the doilie. A knitter may work on several different doilies simultaneously, requiring scores of bodkin pairs. If a knitter lost or broke a bodkin, she was left with the proverbial "odd bodkin".

Image #6 is a group of 10 mixed matrix tatting bodkins.  Image #7 compares an ivory bodkin (upper) to a whalebone bodkin (lower).  Image #8 shows one ivory bodkin (blue ribbon), two whalebone bodkins, and a whalebone knitting hook.

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