Will Cat 320 manual thumb fit a Cat 235B excavator? Thank you for your help!
Depends what you mean by fit. A 235 is almost twice the size of a 320, so not really if you want it to be usable.
I have a 235C. Looks like you need a thumb wide enough to fit the bucket and needs to "mesh" with the bucket teeth. Since the 235 is twice as big (~40 ton vs. 20), even if the thumb "fits" it might take the force of the bucket curl.