On 1/6/21 4:29 AM, Gene Heskett wrote: > how does one maintain access to the bed slots for hold down clamps?
That's the problem with the slotted aluminum table top. Very handy... until you realize it's not flat and/or level. For a small slotted aluminum bed that was flat, I'd probably try to shim it level. If it's not quite flat and the top thickness allowed it, I might machine the top of the T slot bed flat and level, just like a spoil board. If you had convenient access to the edges of the T slots, you could always use countersunk screws to install a UHMW (cutting board) as a spoil board and machine it level. Fly cutters are problematic with a low torque and possibly out of tram spindle that would cause cupping so I use a 1" or 1.5" diameter router bit on my 2' X 4' CNC router. You could use an even smaller diameter cutter on your smaller CNC router. Then drill a series of spaced holes coinciding with the slots and push in T slot nuts from the side to the location you want when mounting your workpiece. It's not that fiddly. Push the machine screws down to stop the nut, lift the screw, and push the nut another 3/8" until the screw drops into the tapped hole in the nut. You lose the continuous 1D adjustment range of the entire slot, but there is already a course spacing between the slots on the other axis. Or you could mount the UHMW bed upside down and machine clearance holes and hexagonal nut pockets an inch apart along the slots, press in an array of nuts, flip the UHMW over, screw it down and machine the top level. If you really want to impress the chicks, mount an aluminum plate with countersunk screws, machine the top flat and level, drill or mill an array of holes and use a thread mill to tap them. Be sure to use anti-seize in those holes and use black oxide screws instead of stainless because aluminum is galling and aluminum and stainless is bad juju. Don't use a cordless impact driver to fixture your work. Probably twenty eleven other ways to get a flat level bed on your CNC router... and we haven't even discussed vacuum hold down tables. :-) _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
