Leica Focusing Tab

So the focusing knob for my 35mm Summicron developed a crack and then fell apart in my hand this morning. I can't find replacement parts online so I'm thinking I have two options. I can jb weld the pieces back together, or I can 3d print a new part. If I 3d print, I may design something that wraps fully around the barrel so that the next time I need to fix this, it does require any lens disassembling. Anyone have this issue with the Summicron? Mine is the "King of Bokeh" version. Made in Canada. I hear the German versions are better, being all metal.