IGUS Linear Slide KOP

[MrForbes]

not having one handy to look at, I'll have to guess as to what it is you're working with...but there does seem to be quite a bit of info on the igus web page, although it will take some effort to figure out just what you have.

http://www.igus.eu/iProsvc/Download....20NW-02-27.pdf

shows some of the carriage dimensions, including hole sizes and threads.

[Gdeaver]

The larger slides that were most common in the kit of parts are metric m4.