(If this subject has come up before, I'm sorry, but searching for "PCB" brought no results)

I want to build a small router to machine PCB material. Not just isolation routing, but actually machining 1/2 way and all the way through the material for model railroad trackwork bases. I have two BSA polymer-nut leadscrews and a supply of nice NOS 10mm Thomson profile linear rails and bearings (both ironically now part of Danaher) squirreled away for just this use.

I am worried about the abrasive dust generated in machining the FR4. My first inclination is go with a "tall wall" Momus-style gantry and keep all the works well above the cutting. But the arguments for the better stiffness of a moving-table bridge design are well-made. However, I have yet to see a well-enclosed (bellows cover or elsewise) moving table mechanism.

My working area does not need to be that large. 4" x 12-14" is all I need. I will be using a Proxxon IB/E (which I already have as my Tormach auxiliary spindle, retrofitted with semi-ceramic nose bearing) as the spindle, or maybe spring for one of Paul Jones' CNConabudget spindles. I will be specifically using a 1mm carbide cutter for the whole process. I do have a decent supply of surplus 1/2" and 1" aluminum tooling plate for the structure, as well as a nice piece of 2" square x 1/8" wall square aluminum tubing which may play well into the bridge or gantry cross-structure.

Do any of you have direct experience with machining PCB which would lead to useful advice?

Thank you,

Randy