Why Was The Stepped Reckoner Unreliable?

Why Was The Stepped Reckoner Unreliable? Its intricate precision gearwork, however, was somewhat beyond the fabrication technology of the time; mechanical problems, in addition to a design flaw in the carry mechanism, prevented the machines from working reliably. Was the stepped reckoner successful? Conceptually, the Stepped Reckoner was a remarkable machine whose operating principles eventually