The desinger states below..
"Tony_G - in reply to DanTexasMan
The part was designed in empirical (inches), but most of the time, people have the import setting set to millimeters in Repetier.
Go to the "Config" pull down and then "Units of imported Object", and set it to "Objects are in Inches". Just remember to set it back, or the next metric model you import will be really big :)
Or you could scale it up by 25.4"
Always good to read the entire comments, odds are your Q is there is one form or another, my one was there too