I won a used 12" Starrett #258 Digi-Chek on ebay for $200. I've never used on of these, but it looks like it's for doing comparativemeasurements with an indicator. It has what appears to be a stack of 11 gauge blocks fastened to a carrier on a ball slide. The carrier moves up and down with a large diameter micrometer. Can I pull the stack apart to insert a longer gauge block, ie one that sticks out to the front? I'd like to use the 258 with my surface plate to calibrate a dial bore gauge. Starrett shows it being used in this manner on their website, but I don't really want to spend $150 for the special gauge block they show being used.