SOLVED. Children's book read in 1978, probably written in the 1960's, about group of boys that build various inventions. [s]

[Whit]

Unfortunately I don't remember exact details, but used these inventions to thwart some rival gang or similar plot device. I recall that the inventions were very involved and were mechanical and electrical in nature.

[beichst]

This sounds like the Mad Scientists Club from 1965. A link is below along with an excerpt. There is also a sequel.

"A strange sea monster suddenly appears on Strawberry Lake, a fortune is unearthed from an old cannon and a valuable dinosaur egg is stolen. Who's responsible? Those seven junior geniuses -- and their wild ideas. Watch out as the Mad Scientists' Club turns the town of Mammoth Falls upside down! "

https://www.goodreads.com/book/show/2...

https://en.wikipedia.org/wiki/The_Mad...

[Whit]

That's it! Thank you!

[Rainbowheart]

The Mad Scientists' Club for the trackable link.