A relative, another John Tyndall of Newcastle ran a forge, coachmaking and saddlery, in the middle of the 19th century, and his grandson, David P. Tyndall (1890–1970), from Chapelizod, became a prominent Irish businessman in the 20th century, who founded the firm D. Tyndall & Sons, as well as several other companies, and consolidated and modernised the wholesale trade sector, introducing the SPAR chain into Ireland.