Also known as 'hackling pins'. In older times there were several trades associated with their manufacture. Hackling pin forgers, grinders, cutters - there was even a hackling pin makers trade union. The steel pins could be about 7'' to 9'' long and were taper ground to a very fine, sharp, point. The pins were then mounted close together, sticking up, and covering the surface of a piece of board, so that It looked like a bed of nails, but with the pins more tightly packed. In operation, scroll down to 'Hackling' here...
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