[routalot]

Don't get too hung up on getting the collet to the table-its a simple thing to add a slab of MDF, skim it and use the new surface for working.The rendering doesn't show any kind of structure I would choose to make from composites with all those tiny webs at the bottom of the gantry side plates.I think a more fundamental problem is likely to be gantry skew with a single central ballscrew.I think you should also be a little cautious about mixing glass and carbon in the structure as they have different coefficients of thermal expansion,it may not be too significant if your working environment has a stable temperature.

[MachineRising]

Don't get too hung up on getting the collet to the table-its a simple thing to add a slab of MDF, skim it and use the new surface for working.The rendering doesn't show any kind of structure I would choose to make from composites with all those tiny webs at the bottom of the gantry side plates.I think a more fundamental problem is likely to be gantry skew with a single central ballscrew.I think you should also be a little cautious about mixing glass and carbon in the structure as they have different coefficients of thermal expansion,it may not be too significant if your working environment has a stable temperature.

I've built several structures using both carbon and glass. Carbon is mostly useful in high load areas. The webs would not be laminated. They could just be plywood with colloidal silica filled fillets . The loading on the webs will mostly be linear. If they did require additional strength the way to do it would be to pre-laminate them and then use epoxy to attach them.


I had originally though to build it with 2 X axis, but thought maybe such a short gantry span it would be ok with the center screw. I've since change back to 2 screws and have ordered 2 new ones. The reason 2 is that the length will now be 1500mm instead of just 1000.

Making the collet touch the bed was fairly straight forward. It requires either a way machined into the Z plate face, or a series of mounting holes for the spindle bracket combined with utilizing the built in adjustment of the bracket to the spindle connection. This router needs to be able to have a wide range of bit lengths from very small engraving bits to 5" ling spiral router bits for shaping corbels.


I think a large problem that will go away in the next round of changes is the flex in the aluminum plates in the Z axis. I can bend the 1/2" 6061 T651 plate I have by hand. Aluminum is strong in point loading, but for weight, fiberglass sandwiches are stiffer.

Anyway, next is a major change in the design of this router.

1. (2) X axis motors
2. EGR25 rails
3. Sandwiched aluminum plates to wood, plywood, or Advantech subflooring. More on Advantech in the next few post. This stuff is unbelievably strong, and stiff, and flat.
4. maybe get rid of the beam underneath although is does add stiffness while transferring mass closer to the center of force.

Thanks for your input. Several times the decision to go one way of the other has been influenced by feed back from you guys.