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Official Q&A: VEX U Robotics Competition 2025-2026: Push Back
2777: Legality of commercial linear guides with integrated rails under VUR15
According to VUR4, Fabricated Parts must be made from legal Raw Stock, and only the profiles listed there are permitted.
VUR5 specifies that extrusions that do not fall under one of the categories in VUR4 are not considered Raw Stock, and are therefore not permitted.
On the other hand, VUR15 allows the use of commercially available bearings, explicitly including both rotational (e.g., radial bearings, bushings, etc.) and linear (e.g., linear bearings, linear slides, drawer slides).
I also reviewed Q&A 1724 from the 2023–2024 season, where the GDC confirmed that drawer slides and telescoping slides are permitted forms of linear slides, and that thrust bearings are considered legal.
My question is about commercial linear guide assemblies (such as MGN-type), which include:
- A special-profile metal rail, and
- A ball-bearing carriage that slides along this rail.
In our intended application for competition, these guides would only be used to connect two otherwise legal structures in a linear “sandwich” configuration, providing smooth linear motion as described in VUR15.
- Question: Since the rail itself is a specialized extrusion that would not normally qualify as Raw Stock under VUR4/VUR5, but it is sold and used exclusively as part of the bearing assembly, is our interpretation correct that the entire rail + carriage system is considered a legal linear bearing/linear slide under VUR15?
This interpretation is correct.
However, the part must be used as intended. The Team cannot take apart the bearing / drawer slide / assembly and use a piece of it in a way that was not originally intended (i.e., as something other than a bearing/linear slide).