NOTE: No middle name appears in any record, except for middle initial "W" in 1940 census.
His World War II registration card states middle name "none".
(See sources below.)
Carol Weisenborn did not include a middle name for Frank on her tree.
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In June 1880 W. F. [Wilhelm Ferdinand] Weisenborn (50), wife Susan (40), children; Lena (14), Henry (12), Natty (10?), Charley (7), George (5), *Frank (3) and Albert (5/12) lived on State St. in the city of Waupaca, Waupaca County, Wisconsin.
NOTE: No middle name for Frank.
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Wisconsin, U.S., Marriage Index, 1820-1907
Name: *Frank Weisenborn
Marriage Date: 19 Dec. 1898
Marriage Place: Waupaca, Wisconsin, USA
Volume: 4
Page: 49
NOTE: No middle name shown.
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On 14 June 1900 *Frank Weisenborn (b. July 1878), wife (b. July 1873) and son Hebner (b. Mar. 1898) lived in the city of Waupaca, Waupaca County, Wisconsin. Frank and Lena had been married 1 year. He was a teamster. Information as it appears on original image of this census.
NOTE: No middle name for Frank.

On 1 June 1905 *Frank Weisenborn (27), wife Lena (30), children; Wallace (4), Winnifred (4), Susanna (1), Louis D. Larson (51), Ferdinand J. Zuehlke (40), Walter C. Nelson (27), Chris Hansen (36) and Louis Christensen (46) lived in Waupaca County, Wisconsin. Frank and Mr. Hansen were teamsters. Ferdinand was a wood worker. Walter was a cigar maker. Chris was a saloon keeper. Mr. Christensen was a day laborer.
NOTE: No middle name for Frank.

On 21 April 1910 *Frank Weisenborn (33), wife Lena (35), children; Wallace (9), Minnie (9), Susan (6), cousin-in-law Alvina Stillman (17), father William Weisenborn (80), mother Susan (70), lodgers; Louis Larson (56), Chris Peterson (43), Chris Hansen (40) and Carl Nelson (29) lived in the city of Waupaca, Waupaca County, Wisconsin. Frank and Lena had been married 11 years, having 4 children, 3 living. William and Susan had been married 53 years, having 16 children, 10 living. Frank was a driver for the fire department. Alvina was a saleswoman at a dry goods store. Louis was a teamster, railway dray [flatbed wagon]. Mr. Peterson was a laborer, on cemetery walks [sidewalks]. Mr. Hansen was a proprietor of a saloon. Carl was an automobile machinist.
NOTE: No middle name for Frank.
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U.S., World War I Draft Registration Cards, 1917-1918
Name: *Frank Weisenborn
Race: White
Birth Date: 18 Jul 1877
Residence Date: 1917-1918
Residence Place: Waupaca County, Wisconsin, USA
Physical Build: Medium
Height: Tall
Hair Color: Dark
Eye Color: Blue
Spouse: Lena Weisenborn
NOTE: No middle name given.
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On 9 January 1920 *Frank Weisenborn (42), wife Lena (45), children; Winnefred (18), Wallace (18) and Suzanne (16) and Louis D. Larson (66) lived on Granite Street at the city hall in Waupaca, Waupaca Township, Waupaca County, Wisconsin. Frank was a teamster. Wallace was an electrician. Louis was a fireman.
NOTE: No middle name for Frank.

On 5 April 1940 Richard Peterson (39), wife Suzanne G. (36), their son Frank R. (10), father-in-law, *Frank W. Weisenborn (64) and his wife, Lena W. (65) lived at 32 Wisconsin St. in city of Waupaca, Waupaca County, Wisconsin. Richard was a lineman for the public utility. Frank was a tavern manager.
NOTE: This is the only record showing a middle initial for Frank.
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U.S., World War II Draft Registration Cards, 1942
Name: *Frank Weisenborn
Race: White
Birth Date: 18 Jul 1877
Birth Place: Waupaca, Wisconsin, USA
Residence Place: Waupaca, Wisconsin, USA
Military Draft Date: 1942
NOTE: World War II registration states middle name "none".
Relationship to Draftee: Head