Mitre joins sound simple enough, however there are many ways to get them wrong.
Using a maple architrave make a border around the MDF sheet. Later were
going to add a mirror.
To cut the first mitre we use a mitre box from
To ensure the correct fit use this mitre as a template for the rest of the
cuts. Measure the other mitres face to face or back to back checking for
Repeat the process for a matching pair- tidy up the joins and glue together.