read the texts in inches and turn them into mm

[taldeitagli]

Hello everyone: I have a large amount of drawings created with dwg units in inches to turn into mm.
everything works until I find myself changing the texts
I wonder if there is a lisp that reads the texts (excluding quotas) and when it finds an expressed value in inches it turns it into millimeters

 

[dieva]

How are the thumbs represented with " (virgolette) or '' (apostrophes).... can you post some texts containing the measure?