So after years of using various garage sale planes in as-found conditions (not very well, I have to admit) I finally have some time to improve their condition, and perhaps my success in planing. One of the planes is a #4 Stanley.

After a fairly large number of hours spent lapping the bottom to a reasonable semblance of flatness I decided to clean up the sides a bit as well when I found a crack, which you might be able to see in these photos.
IMG_0044.jpg IMG_0043.jpg

Do I pitch it and start over with a new plane? I have no skills or equipment in welding, brazing or silver soldering. It took a long time to get it flat and I still don't want to accept the concept of sunk cost ;-). (To make matters worse, because the blade was badly pitted I ordered a new blade and chipbreaker for it, which is now on the way.) I suppose a #4 is about the easiest plane to find.

I'm assuming that this crack is a Bad Thing that will have some bad outcome when I use the plane, presumably flexibility between heel and toe that will keep me from getting a flat surface. Is that correct?