Black Friday Deal got me :)

   

this is what i went with and the cheapest is what drove this decision. Since i have never done a plasma machine before top-of-the-line stuff is is not something i want to do on a first-time build for plasma., these drives are rated for 42V so 36v is safe and should do what i need them to do. i plan on keeping the gantry very light, plasma should not need anything to rigid. my thought is 11-gauge square tube should do fine, i honestly don't think you need much more than 1 linear rail on the gantry maybe 2 on the Z but 1 there too would probably be enough.

i will be doing my planning in fusion 360 to work out a final game plan, i might try to design things so i can add a rotary later down the road if i want to get into than later. This straight torch is pretty long so a z with lots of travel is probably something i will factor into a design. Z height is something i would avoid in a milling application but with plasma it should not matter much.

I have those drives, they are good, they have issues, and for sure will die at 42V!
Those use the TB67S109 chip (IIRC) that has the absolute max rating of 40V or 42V, and a working rating of 24V, i have them running at 27V without issues for years, but i would not go any further than 32V.
They have good microstepping, have some protections, and do not die like TB6600, also less sensitive to EMI than TB6600.
Also cheaper than TB6600.
Max current is 3.5A, should be plenty.

listing said 4A max and said it was an upgraded version i have not picked up any power supplies yet. usually China ratings are exaggerated so i never go to the max. i think the motors are rated at 3 A. I will keep that in mind regardless. maybe i will get some sort of manual with them when they get here? I will have to wait and see. but if i smoke a $7 drive it won't hurt to bad

I've been gathering and planning quite a bit. My motors and drives came in yesterday and another batch of goodies should be here in the next few days.

I'm still working on my finished plan but have a much better idea of how thing will look coming together.

But with a floating head with a magnetic breakaway and about 5 inches of Z travel i came up with this so far.

 

I started to actually do some work but it was short lived but when Christmas and new years gets here i will have a lot more time to build things. But as of now i have a gantry beam and 1500mm rail to mount on it and all the bits to build the Z axis so it a start my lead screw for my Z needs to be cut down to fit the build. 4 start screws are limited in choices for some reason.

but everything is built around 3 inch square aluminum tubing. came across a drop of this for the gantry beam as well. i'm using 12 mm round rails for my Z. also decided to change some things on my floating head concept. after looking at it for a while i seen a better and easier way to do it  

   

So I picked up a self-centering 4 jaw chuck. it's not very big but will hold 4 inch square tubing from the inside. i was looking at several ways to make a steady rest for longer tube but the draw back is you have to have around a 6" bore to pass 4" square tube through. bearings beyond 90mm ID's are very expensive. i might have found a work around but i have to test a small design and scale it up if it works. A steady rest for round tube is pretty easy but the square tube gets a lot more involved unfortunately. it would be nice if a cheap self-centering programable clamping system could be don cheaply but that solution is yet to be found
i have an idea for that too but until you build and test it out all it is an idea but if that would work the little chuck would get phased out