Dropping the Y-Axis Rails

I have just placed an order for a new machine which will be the 2nd X-Carve I have owned. My new machine will be a 1000mm x 1800mm. In the new machine configuration I am considering a modification to drop the top of the Y-axis rails to be just below the surface of my waste board. To achieve the rail drop mod, I want to fabricate taller gantry side plates to increase their height. I don’t want to sacrifice material clearance, so the gantry X-Axis rails would effectively stay at the elevation it is relative to the waste board. Just the Y-Axis steppers, V-Wheels and the Y-axis rails would drop. My new gantry side plates would likely want to be a fuzz wider to offset any structural torque caused by the taller gantry. Has anyone else performed a mod like this?

Why do I want to do this?

  1. As a space saving move, my new machine will be placed at the end of my miter station. The top of the waste board will be the same height as the miter station working surface. I want the extra run-out surface.
  2. I am also adding a downdraft system to the X-carve and want to be able to have the large X-carve surface double as a sanding station.
  3. Lastly, I always feel like I’m working over the rails… they get in the way on the longer machine.

Thanks for reading and providing constructive input!

After I built my 1000x1800 extruded aluminum torsion Box with MDF skins, I considered doing this same thing. However it would have required me to completely disassemble my machine. What a pain that would have been. If I was to rebuild another machine using the same set up, I would consider this especially with a functional CNC to cut the new plates.

Please share your progress

Interesting. I believe your the first person to lower the rails vs raising them. I believe the use of the cutting surface for multiple work stations is also unique. Please keep us updated on your progress. Along with problems/ solutions.

With the longer machine, I did/will work from the side more. Especially in the configuration of the work area in my garage. I’m essentially starting from scratch with a shop rebuild. I will post some imagery when I get time to wrap it up.

This is what I’m planning. I increased the height by 66mm and the width by 25mm. Still working with support structure under the waste board and how the downdraft system is going to be configured.

For the substructure you can just connect each Y makerslide with the same size extrusions. About 10 -1000mm extrusions that run parallel with the X axis should suffice and make for a sturdy structure. This would allow you to not need a separate substructure. You will just need to place a few feet underneath to raise it off of the table surface to allow for the clearance of the plates where they go below the surface of the Y makerslides if it’s sitting on a bench or table. Or instead of feet you can install a rolling cabinet system underneath that is narrower than the overall machine. In this cabinet you can enclose your shop vac for dust collection and even a second shop vac for a vacuum table. These cabinets will allow you to soundproof the shopvacs. (Just properly design the cabinet). The cabinet will also be great for additional storage

Check out this video for the Vacuum Table. It’s not the only method but good food for thought.

I am helping a friend build his CNC. I believe this will be the method we will be using. Very logical.

That’s an interesting vacuum table concept. I didn’t realize MDF was that porous!

Extremely porous.

If they were to surface each side with a skim cut to remove the hardened outer skin, it would be even more porous and allow for an even better vacuum. It’s possible the 6”x6” would hold tight if they had removed the outer surface.

Think of how hard it is to finish the edges of a MDF project. You can keep adding finish and it keeps soaking it in. The same concept works for the air when vacuum is used. The only difference is when the finish is allowed to dry, it hardens and starts to slowly seal the endgrain. That’s why it’s better to apply one coat to the end grain, allow to dry, and repeat until it is sealed.

You can but 20 coats of finish on while it’s wet and it will continue to soak in (swelling the MDF) and does not completely seal. Where as if you give it time to dry in between each coat, it will stop absorbing around 4-6 coats.

When it comes to vacuum fixtures, the porousness is an advantage unlike finishing.