There is a top view pic of the OPs slide that looks unusual. It has holes in the top that none of my slides have. If the slide was purchased from a member of the engineering dept, it could be the first try, of what we called "proof of concept". My eng. dept. had all its own machinery and parts.
If the slide had some screws/pins sticking out of it but it worked. You
proved your concept was viable and clean up was the next stage.
The first go around did not have to be production ready. Just saying.

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Mike 2796
SoFo Bunch member