
If you lose any bearing balls in one of these, consider it completely useless. 3/32" bearing balls are too large and will make the rails very hard to move. If you get a defective rail it will miraculously be even worse if you try disassembling it, cleaning and lubing it. Of the seven rails I have, one is so bad that it won't slide even if you hold the assembly by the carriage at a 90 degree angle.

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