1) From the fourteenth century the custom of classifying nails according to the original price per hundred became increasingly common, so a fivepenny nail was a nail which cost 5d a hundred.
The accounts for the rebuilding of Trinity House in Hull, in 1470, record the purchase of ‘2C of four-penny nail 8d’, and even of ‘2C of three-halfpenny nail 3d’. After the prices changed, as they began to do in some places before 1500, the names persisted and were eventually used to designate the sizes of nails: 1538 pro v.c pennye nayll 2s 6d, York
1548 A m penny nayles, 5s, York. Examples of different sizes are frequent from this time: 1539 Item for sixpenny nalles and dubbyll spykyng, ijd, St Michael’s, York
1596 one hundred of tenpennye nayles & one hundred of sixpennye nayles for naylinge downe lead and sarking bords on the roufe of the churche, Howden
1704 for 7 Firrdeales and 100 12d. nayles, Camblesforth. Most references are from tradesmen’s accounts of one kind or another so the following extract from Henry Best’s Farming Book is of real interest: 1642 a barre ... goeth straight downe the middle of the spelles and is nayled to each spell with a single 8 or 10 pennie nayle … if the barres should bee cutte soe thinne till a 4 pennie nayle woulde nayle the swordes and spelles togeather, they woulde not bee halfe soe stronge, Elmswell.