What year and where was your grandfather born? Do you know his mother's name?
Public records/ census data only goes to the year 1940. This might be Hubert G through 1930?
US Census, 1900 ED 540 Borough of Manhattan, Election District 22-23 New York City Ward 21
https://familysearch.org/pal:/MM9.1.1/MSK9-HMR
head Frederick Norton M 49 ENG
wife Dorathy Norton F 39 CAN Eng
dau Dorathy Norton F 11 CAN Eng
son Cecil Norton M 9 CAN Eng
son Frederick Norton M 7 CAN Eng
son Vincent Norton M 6 FL
son Charles Norton M 1 NY
son Hubert Norton M 0 NY
United States Census, 1920 Westchester, NY
https://familysearch.org/pal:/MM9.1.1/MV3N-MYY
self Dorothea Norton F 59y CAN
dau Dorothea G Norton F 29y CAN
son Cecil Norton M 28y CAN
son Frederick Norton M 26y CAN
son Vincent Norton M 25y FL
son Hubert G Norton M 19y NY
U S Census, 1930 Danbury, Fairfield, CT
https://familysearch.org/pal:/MM9.1.1/XMPS-RKK
head Andrew Olsen M 61 SWE
wife Hulda Olsen F 63 SWE
dau Esther C Olsen F 34 Connecticut
dau Hulda A Olsen F 24 Connecticut
son-in-law Herbert G Norton M 29 NY/ENG/CAN
dau Edith A Norton F 28 CT