Their hard work paid off yesterday, with the official launch of their product at the prisons Te Tirohanga Unit.
Getting to this point had not been easy. There were disagreements - over the designs, and where the boards should be sold - and some early worries about how the partnership would work out.
"I never thought we'd get along," an 18-year-old offender said. "But we got to mix and mingle with the St John's boys, and bring together our ideas."
With obvious physical barriers, working together required some "innovative thinking". The boys had been able to meet several times face to face, and other times looked for ways technology could help bridge the gap.
The Hastings St Johns pupils were able to carry out market research, and provide feedback to "our brothers in prison", who then made the boards with the help of corrections staff at the prisons on-site workshop. They could make up to five per day.
The leadership was shared between two CEO's - St Johns student Jake Gunn, and an 18 year old youth offender.
During the launch, the 18-year-old co-CEO said he was proud of what they had achieved.
"We see a different world where the reaching out between young people can make a real, and meaningful difference.
"Brutha's is different from other companies. We have an innovative model, we have identified our limitations, but have embraced our collective strengths."
As Jake was not able to attend the launch, deputy CEO Rhyva van Onselen explained the process behind their product - each set is made of recycled rimu, embossed with a "unique Maori design", with four pieces that interlock like a jigsaw, and can be used as a chopping block or serving platter.
Due to their size and quality, the sets retail higher than others on the market - but by the launch yesterday, 16 of the 20 sets made had already been snapped up through pre-sales.
Attending the launch yesterday were those who had helped co-ordinate the project - including staff from St Johns College, Corrections, the Young Enterprise Scheme, and Hawke's Bay Chamber of Commerce.
St Johns College principal Paul Melloy said he was "immensely proud" of his students and the inmates, who had all changed from the experience.
"They had to overcome a lot of barriers. There were some fears with the students, and their parents. When they first visited the prison they were shouted at from one of the units...the way they've blended, and joined together [with the inmates] is amazing.
"I've been in education for 30 years and I've never seen anything like this."
Prison director Nephi Hall said the partnership between the young men showed that "no matter where, and what walks of life we're from, we're all in the same community and we need to work together."
As well as learning about business, and joinery, Mr Hall said the project had shown the inmates that they had potential, and that there was a different path for them.
"The [St Johns students] are great role models for these boys. They're all the same ages; they've just taken different directions in life."
One of the team, an 18-year-old inmate said the programme had given him "heaps of business knowledge".
"It's something that can add into my life, and my future, so when I get out there I can use it."
The students idea was made possible through the work of their teacher, David Ivory, who thought this was a national first, with students and inmates doing all the same work, to the same standard.
YES Hawke's Bay regional coordinator Karla Lee said the process that Bruthas went through was the same as those from other schools. Some parts had to be altered to cater for the offenders - such as the "Dragons Den" competition, which was individually for the team at the prison.
"The only difference was we had to come to the mountain," Ms Lee said. "That's what it takes, is for everyone to come together to support it."
The success of the partnership had inspired Corrections to take the model elsewhere, such as working with hard-to-reach communities, and schools.
More "Just Boards" will be created for the team to sell at tomorrow's Farmers Market at the Hawke's Bay Showgrounds. They would also be stocked at two Napier locations - Hapi Café, and Fuse Café, which the team said had "taken a risk on our vision".
In keeping with the sustainable theme, the boards are sold inside an upcycled coffee sack with drawstring tie - made by a different group of prisoners.
The sets retail at $150 each, with profits going into a "community fund". It had not been decided what the fund would be used for yet.