Skip to content

Riddler, Riddling

Riddler, Riddling.  The sieve and the process for sorting out undersize and malformed blanks. Before coining, production run blanks from the blanking presses are dispersed over a vibrating mesh slightly smaller than the size of an acceptable planchet; clips and other debris fall through the mesh leaving correct size blanks above which flow to a separate hopper. Blanks with clips, both straight edge and crescent shape – formed from blanking near the edge of the strip or already blanked areas – are found in the rejects (which are later melted for reuse). Clean scrap from this source, scissel, is excellent for recycling because it is already the correct composition metal. Correct size planchets can then be annealed, cleaned, upset and fed into the coining presses. Mechanical riddling replaces expensive human visual inspection.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators


Roger W. Burdette, Editor

NNP is 100% non-profit and independent // Your feedback is essential and welcome. // Your feedback is essential and welcome.