Insunder

And herein also her forebeam to which her bowsprit was fastened, cracked clean insunder; and some of her timbers likeways in the hold we found defective.

Source: wiktionary

For as in a watch, or some such small engine, the matter, figure and motion of the wheels cannot be well known, except it be taken insunder and viewed in its parts; so as to make a more curious search into the rights of states and duties of subjects, it is necessary, I say, not to take them insunder, but yet that they be so cosidered as if they were dissolved;

Source: wiktionary

Secondly. Spiders thus hanging, when they have shot out such a thread as we mention'd, seem to have power at their pleasure to snap insunder the thread they hang by, and sail away with the other.

Source: wiktionary