This step and the previous one list the mandatory tools you need to build the Bear frame.

Having a quality square will help you to build the Bear precisely. We recommend a 200mm long machinist precision square, ideally with standard DIN 875 / BS 939 (any grade).

If you don't have such a square or want to use a lower quality one, check these videos on how to test and fix your square:

How to Square a Square by Wesley Treat: https://youtu.be/FNpAQHrNpNU

How to Square a Square and Make it True by Wood By Wright: https://youtu.be/enEYzTXg2Jg

Caliper, 150mm long minimum. If you don't have a caliper you can use a steel ruler. (A vernier caliper is generally more accurate than a digital caliper, at the same price point.)