In the offhand chance I need to mill or drill holes in material 3" thick for this project I am working on I am at a conundrum. I was going to use an mdf spoilboard with threaded inserts hammered into the bottom of the spoilboard at 2" increments in a grid pattern except around the left and bottom sides where I will have dowel pin holes every 1" for work alignment on repetitive milling operations on two sides of a workpiece.
Anyway, is it better to cut out a cavity in my OSB table top (I was going to glue three 0.44" OSB pieces and a 1/8" hardboard on top together) and place the spoilboard in that cavity or can I just adjust the Z-scale in Cura and mack the feet 3/4" taller?
I already printed out a copy of the original feet and the scaled up feet. The only noticeable affect on the z-scaled feet is the horizontal bolt to hold the conduit snug inside the feet is oval due to the adjustment to z-scale…
If you want a higher Z, take longer pipes. The recommendation is to build a drop table though, because the higher Z is, the less stable it gets.
You can also put the feet on strips of wood, that’s what I did for my first build.
I would have to increase the pipes with my foot heightening idea.
How would putting the feet on strips of wood be different than upscaling the z-axis of the prints of the feet? Is the plastic just too easy to deform compared to wood you mounted your feet on?
I can’t see how increasing the dimension of the plastic parts would be preferable to longer tubes or putting the feet up on blocks.
I like to try to think of things from first principles. The part that matters is the X/Y tubes and everything between that and the tool head. The Z tubes and feet are just how you raise that off the table and maintain squareness against some of the torques applied. Ultimately you want that to be as rigid as possible. Longer Z tubes are probably fine for most cases. The best is likely to be some kind of boxed in frame that barely clears the trucks. The worst would be something like making the legs out of pool noodles.
If you don’t think you’ll use this capability much and it’s only drilling (no side load), then longer Z tubes are a super easy approach that mean you may not need to do any work re-squaring your machine when you take it back to ‘normal’. If you just want something simple then some 4x2 blocks under the feet are likely to be more rigid, I’d think, than taller plastic pieces.
If you think you’ll be using it heaps, you could make a box-frame that sits on top of your table and raises the platform in a way that’s quite rigid/braced. That’s basically the same as making a table and then cutting a hole in it to mount taller workpieces lower, you’re just getting there from a different approach, logically thinking.
My logic is that if the plastic pieces were more rigid than tube, the Z legs would be entirely plastic. I don’t think that’s the case so I’d want to keep that transition from plastic to metal tube as quickly as possible. I think the metal tubes themselves would be less rigid than a framed structure, so if I wanted ultimate rigidity then I’d be trying to get the X/Y frame mounted to something that has a lot of rigidity in all directions (X/Y/Z, yaw, pitch, roll etc.) which is basically what your table should be.