Question

how do the iron blade in tools is fixed to the wooden handle​

Answer 1

iron blade is as large as wooden handle and it's half is under the wooden handle

that's why it is fixed.

Answer 2

First, the ring in the iron blade of spade is heated. Heating of the blade leads to its expansion and thus the ring gets bigger. This happens because metals always expand on heating.The metal bladw is then fitted easily into the wooden handle. After this, cold water is usually poured on the iron blade which leads to the contraction of the expanded iron blade. The spade can also be left to cool down, undisturbed so that it is firmly fixed. The blade is attached firmly to the wooden handle of a spade in this process.