[Wolfesmetalfab]

I am preparing to build a smaller plasma table (approx 2.5ft x 3ft to 3 x 4) as an addition to a welding area workspace. It does not have to be super accurate, just to be around to quickly cut out parts that may be needed during fabrication. The cutter hooked to the table will be a Thermal Dynamics Cutmaster 51. Also Probably be using Mach 3 from all the reference I see to it, unless there are other suggestions. (I currently use Autocad) I am excited about this build, and looking forward to getting started.

Selecting the proper parts will probably be the hardest part for me. I want a decent machine, but it does not have to be super accurate, or super expensive either. I am going to start posting questions as the come, and hope for answers or tips, and when I am ready to build, I will post pics and descriptions.

Thanks In Advance.

First, I was thinking of using some ball screws that i have laying around, I believe double start, 6 tpi, I thought might work, but looking on here, you guys say no, go with racks. Correct?

From searching about gear racks, I come up with a 20 tooth, 20 pitch, 20 degree PA would be the best bet, and gearing it down with a short pulley belt sys.

Electronics
Following some more searching and links, I found these guys. (Probotix)
http://www.probotix.com/index.php?vi...&product_id=52
Would this do me well for what I am wanting, and is the price decent? Are the drivers/motors decent construction.

EDIT: another option http://www.xylotex.com/3AxSysKit-425.htm

Other suggestions about size/torque, etc?

Thanks again guys, and I look forward to being a part of this community. :wave:

[millman52]

Typically R & P resist the dust & grit better than the ball screws. For ths size table you are suggesting, If your screws are long enough for you to improvise some sort of telescoping or self storing covers for them they would be great. That is providing you do the math & see if you can get the speed required to use plasma.

For gear rack: the 20 tooth 20 pitch is fairly common.

Probotics, I have only heard of them & noticed them being used in 1 build of a plasma table. (Not being negative, Just my personal observation)

Xylotex, I haven't used their products personally. They seem to have a great reputation with service after the sale.

For the size of your proposed table the 425 oz in NEMA23 steppers should be adequate.

I'm not sure about using any part of a CNC operated table for a welding bench. Someone else here I'm sure can answer that question for you.

[plain ol Bill]

There is no way I would use a welding machine on the same table w/ a CNC plasma (or any type CNC machine). Welding sets up high frequencies that can burn up boards and inernals on this type equipment. Been there, done that, and I can tell you first hand that it can get really expensive! If I HAD (absolutely HAD) to weld something on a CNC table I would make sure everything connected to it was unplugged and the work ground was hooked to the part I was welding on without the electrical path going thru any other parts.

[Wolfesmetalfab]

LOL...misunderstanding, although I do appreciate the forwarnings!!

Im not planning on welding on it, what I meant, was that I am going to add this plasma table unit in the welding area, so that when fabing and welding up custom jobs, brackets and additional pieces can be made quickly in the same workspace as the welding is being done, and because of the welding area size, I am not making a large table. No welding, or grounds will be touching the plasma table.

The ballscrews alread have a protector around them, see pics I posted in other thread that was focused on using the ballscrews as a drive.

http://www.cnczone.com/forums/showth...800#post525800

I am mounting them so that the small uncovered surface is upside down below cutting height on the x, so dust and sparks shouldn't be able to get inside. And on the Y, maybe upside down, or sideways opposite of the torch. I think I will get a linear slide mechanism off of ebay or somewhere for around $30 with about 3 to 6 inches of travel, that would simplify and clean up the gantry, I will use skate bearings for the rest of the machine.

I think the xylotex sounds good then, is the 425 too much, or should I go with the 269s for speed wise, could I get by cheaper, or is $325 shipped real reasonable? Then the only thing that I would need electronic wise (already have a cpu) would be the THC, thinking of the thc300, right?