Hello and welcome....
We greatly advise NOT to build wooden karts.... YA its been done... and people have lived, and other people have darn near been killed....
A member from Chile, a number of years ago made a wooden kart, out of some local hardwood.
He was almost ridden off the road and bailed harshly, broke his kart.. he had a brake setup from a motorcycle and was pretty reinforced... he did live however... but could have rode off a cliff.....and aparentlly was pretty close to...
Point being... Find something and fix that up, bolt together and wooden karts ar not as strong as welded and braced designs....