The Juha Kustaa Kangas family that settled in Ironwood is not the same family as Juha Kustaa Hermaninpoika Kangas born 1881 in Alaharma.
According to a Family Tree posted on ancestry.com, Juha Kustaa Hermaninpoika Kangas married Selma Erki Hirvikoski. Selma was born in Toholampi. They married April 9, 1904 in USA and had 10 children. This family may have lived in the Fitchburg MA area and returned to Finland. I cannot find them on a census here.
Juha Kustaa Hermanin Kangas (Korkiakangas) was born in Alaharma March 10, 1881. He had brothers Nikolai, born 1887 Alaharma, Kaarle born 1890 Alaharma and sister Lisa born 1884.
Church records state Kaarle and Nikolai came to the USA in 1906. I found Nikolai on a Boston ship manifest in 1906 going to Fitchburg to his brother Johan Kangas.
Their father was Herman Korkiakangas born November 1, 1857 Alaharma, died 5. 1892 in Canada. Their mother was Sanna Maria Isak's daughter s. Lauri born May 21, 1857 in Kauhava, died 8.1936.
The children of Juha and Selma Kangas are Veera Inkeri, Sylvi Maria, Leimo Johannes, Selma Johanna, Väinö Vilpas, Martti Nikolai, Tyyne Elisabet, Aune Ihanelma, Aarne Olavi, Lauri Veikko.