I have shortened a glass scale, but not a chronos one so you may need to adapt the method.
On the end that you are going to chop off, remove the end piece. Slide the read head to the other end. Fill the scale with cotton wool or tissue to try and stop grinding dust into the read head. Slide this packing upto the read head making sure that it's past the cut point. Mark the cut point on the outside case of the scale. I used an angle grinder with a 1mm thick cutting disc. Cut it so that the glass is supported by the metal in the direction that you are going to cut. Then go for it. Take it easy and do not force it though.
Just stick the end piece back on with sealer.
Best of luck.
Cheers
John
Edit , I see some has typed faster than me and posted a better desciption with pics.
Edited By elanman on 19/09/2021 08:45:15