Well here goes... Aluminium frame router design

[Boyan Silyavski]

Maybe i am being thick but i cant see how flipping the rails will introduce vibration, looking at the conventional method then the spindle is mounted away/lower from the bearing blocks whereas my design is a constant length of zero from the base of the spindle clamp to the bottom of the bearing block. Is it the spindle clamp causing the issue or is the spindle too low in the clamp? How low can the spindle be in its holder?
Cheers

Whatever you do if you dont:

-use long size 20 bearing blocks
-space the bearings that the front plate slides on at least 260mm from outside ends/each long block is 90mm long/
-fix the rails on the front plate back

you will finish with a machine incapable of working Aluminum and maybe not so precise on hard woods.

There not so much to understand, the rails +the bars they rest form ribs that prevent long axis bend. That simple.

Front plate must be 12mm steel backed with steel bars below the rails, or at least or 20mm aluminum backed with aluminum bars. Using 2 spindle brackets would make things even better as the spindle will add stiffness.

Linear rails are cheap, so that will add very small amount to the build. See 200mm travel axis made same way as we speak that reaps/i can not help say it / fully extended , through aluminum without any chatter . here post #109 and how looks finished from 12mm steel plate a bit up at the same page