Plasma table + 4th axis

Hi guys, 
First of all I want to thank all the people who have posted here over the years to make this place such an amazing wealth of knowledge. Then I want to thank all the people who have put in the time on the software to make linuxcnc and qtplasmac so great. Thank you guys so much. I will attempt to stand on the shoulders of giants with my build. 


I am looking to build a plasma table with a 4th axis off the side for cutting and marking tube. Ive been lurking in this forum for over a decade and built my first cnc router back in 2011. Now its time for a new cnc and I'm planning on using servos, stmbl drives, ball screws (perhapse rotating ballnut), 5x5 water table, powermax 45xp, and build it for high acceleration. 

I plan on documenting my progress here to hopefully inspire others. 

As of right now I am planning my z stage to have a sharpie, a scribe, an alignment laser, and a torch with hypersensing and collision sensing.


In my reading this forum I have observed people strongly encourage a floating torch design. Is this still advised when using the hypersensing method with the thcad? 

You definitely need the floating head with hypersensing becasue you need some overtravel to allow the torch to come to a rest. I generally run a fast probe speed so its required.

I've got a feeling my float switch sensor is broken so never miss it but need the overtravel.

I don't think roating nut designs are that hard if you have a lathe.  A wheel bearing would be perfect.

Wow thanks for the quick responses guys. I'm sold. Rodw, do you have any idea how much overtravel you use? 
Im trying to minimize parts and lengths for lightweight. I've always enjoyed the gram weenie game. 

I understand the power ic is gone. Such a bummer amd i hope the brilliant guys behind the project find a way to get around that. I am lucky enough to have a friend who has some drives i can buy. I understand from him that they work great and interface with linuxcnc via smartserial really well. Im excited to try them.

I am plugging away on the design of this machine. Funny how much i underestimated the hours needed for the design.

Another question for the forum, i have seen mention of cutting parts fully submerged but not much info on why. Do any of you fill the water table high enough to do this or is it rare. If so whats the main reason?

Interesting. That is even deeper than I thought. I originally had the water level stop at the bottom of the material. I will add another inch or so. Thanks for the reply.