The Summa First 20 was a mechanical adding machine manual writer built by Olivetti from 1960, designed by Claus Capellaro for the mechanical part and 24 Mar 2015 2 Nov 2017 Olivetti was stablished in Argentina in 1932 and during decades Logic comments: Memory organization: The Olivetti Summa Prima 20 . Accesories: Dust cover, user manual in Italian and quick reference guide in Spanish. 24 Apr 2018 Summa Prima 20 Sterling) Olivetti Summa PRIMA 20, S/N 5453931. Manual, 10/11 digits, Sterling currency. Dimensions: 190W x 285D x 130H22 Jun 2010 10/11 Model: OLIVETTI SUMMA PRIMA 20 Serial Number: 550027 Dimensions: (ca.) Width = 9 " / 23 cm Depth = 14 " / 36 cm Height = 5 Vintage 1960s Olivetti Underwood Summa Prima 20 Manual Adding Machine Calculator | eBay. This vintage Olivetti adding machine is in excellent condition. It is in full working order with all original parts. Plugged this in and it works great. I tested the print 14 May 2017 Mechanical calculators: Olivetti Summa Prima 20. * Back to Offline Hours There are still many Summa Prima 20s around, some made in Brazil. I obtained the Olivetti Summa Prima 20 User's Manual, in Italian. 16 Aug 2015 MTE's purchase history for new Prima 20s stretched from 1962 to 1966, and the Rare Vintage Olivetti Summa Prima 20-7/8T Manual Adding