Plasma Table Build - Plasma Bot 4.0

[geezer]

The table is square, but one of the middle legs is out of line.

A minor hiccup on the base,,,it's the top rails that count as far as alignment goes,,, and they can/should be adjustable to run parrallel,,,the base can be out of square etc,,,and it will be once you load the slats and add weight to the table,,,,

[SeanMurphy265]

For the most part my table portion is finished. I still need to add two pieces of tubing across the top for support. I'll make a run to the supplier for another stick of 2x2 square tube. I had to straighten my center legs. I should have ran two long pieces for my lower rails. I guess I had a brain fart when I started building the table. I have a little bit of welding left. There is a lower cross brace on the bottom center section that is not in the picture. I had to take it out so I could square up the middle legs. I started to let the middle legs slide, one side was leaning out and the other was leaning in. The table is square and the outer legs are square, but the middle legs made the table look like crap. I might sell this table one day so I figured I better fix it, and it bothered me how bad it looked!





Power Arc 140st 7014 3/32 @ 93 amps - I absolutely love this welder! I use it more than all my other welders combined. It's handy, powerful, and easy to setup.

[SeanMurphy265]

I have to order my gear rack, concentric bushings, 1/4-28 bolts, and some type of sleeve for the bolts. The gear rack is the biggest expense I have left. Everything else I spend is more or less bonus stuff like torch height control and a z-axis. I have a linear actuator for a z axis I'm not sure if I will use it or not.

[sportbike]

Looks good Sean.

You may find it to be a bit more stable and remain square after use if you add in some light duty X-bracing to triangulate the table a bit. This could be some angle, small square tube, round tube, etc.

Nevermind, I see the corner gussets going in now. I think I's still add some more in, if nothing else, to increase the stiffness for future loading or moving the table.

I look forward to seeing your first cuts over the summer.

[SeanMurphy265]

Ok so I just ordered the rest of the parts I need for the table.
Concentric and Eccentric bushings from PBC linear -$45.65
Gear Rack, SS nuts and bolts, bronze bearing sleeves, double sided tape $191.09
I spent $7.00 at tractor Supply on some other fasteners that I need.

And.... as I am typing I realized that I did not or gear rack for my Y axis.... which will be $36.00 more $$$ On the positive side that is all the necessary expenses that I have left. I can get the table up and running. I do expect to spend $65.00 for another stick of tubing, but I may just go with angle iron.

Torch Height Control and Z axis ($250.00 touch and go) will come later, I figure I will add a touch and go before THC.

[geezer]

Glad to hear you are on budget,,didn't think that was possible,,,THC on a big table is almost a must, due to the flexing of the sheets etc...had to laugh at your use of the comealongs,,,been there done that myself,,,they are handy for that kinda stuff...hope to see more of your build,,,a 4 x 8 table is a big project,,,looks simple until you actually get into doing it,,,lots of alignment and measuring,,,then there is the distortion of the weld pulls on the parts,,,takes some doing,,,a real learning experience,,,,after this ,,you will be qualified to build anything..

[SeanMurphy265]

Glad to hear you are on budget,,didn't think that was possible,,,THC on a big table is almost a must, due to the flexing of the sheets etc...had to laugh at your use of the comealongs,,,been there done that myself,,,they are handy for that kinda stuff...hope to see more of your build,,,a 4 x 8 table is a big project,,,looks simple until you actually get into doing it,,,lots of alignment and measuring,,,then there is the distortion of the weld pulls on the parts,,,takes some doing,,,a real learning experience,,,,after this ,,you will be qualified to build anything..

Well, if I do this again I will go with 3 linear actuators! It will add to the cost, but cut the time in half.

[SeanMurphy265]

My gear rack arrived yesterday afternoon from McMaster 3-pcs 1/2" 20 tooth / 20 pitch (I think!) All my other fasteners arrived as well, and now I should have everything to at least get the table running.

[SeanMurphy265]

I'm not sure if you can tell by the picture, but the top piece of tubing (near side) bowed a little. How can I get it back straight? It has about a 3/8" bow. Where should I put heat to see if that would help?

[geezer]

Hi Sean,,,question ?? how do you plan on attaching the gear rack to the table,,,epoxy, machine screws or what ??

[SeanMurphy265]

I plan to either weld or bolt 4 12" pieces of 2x2x1/4 tubing on all four corners, and then bolt my rails to the corner tubes. The plans for the kit call for the gear rack to be double sided taped with this heavy duty tape from McMaster. I purchased the tape, but I am considering drilling and taping holes for set screws and loctite the set screws. From what I have read no one has not had an issue with the double sided tape, but I'm sure vibration over a long period of time will cause the rack to come loose. I have also considered welding some small 1/"2 tabs ever 6" or 12" and using machine screws to bolt the rack in place.

[geezer]

I plan to either weld or bolt 4 12" pieces of 2x2x1/4 tubing on all four corners, and then bolt my rails to the corner tubes. The plans for the kit call for the gear rack to be double sided taped with this heavy duty tape from McMaster. I purchased the tape, but I am considering drilling and taping holes for set screws and loctite the set screws. From what I have read no one has not had an issue with the double sided tape, but I'm sure vibration over a long period of time will cause the rack to come loose. I have also considered welding some small 1/"2 tabs ever 6" or 12" and using machine screws to bolt the rack in place.

The reason I asked is someday I might face the same problem,,,not sure if you can drill & tap,,,don't know the rack's RC value,,my self I can see me epoxying the rack to a wide piece of flat bar and drilling and tapping that to the rail

If you are going to try to take out that 3/8 bow,,you might consider a hacksaw cut at the bow middle and hammering or jacking it into position and rewelding and grinding,,,not a pleasant job,,,heat at this stage of the game won't do much,,,,,could position a timber along and/or above the rail to give you some thing to jack against....just a thought

[SeanMurphy265]

I saw on CNC Zone where someone tacked their gear rack.

[Rodsmachineshop]

I have seen a few cnc tables were there just pop riveted at the ends with aluminum rivets and a thin bead of glue underneath since all the pressure is pushing down on rack could use jb weld but never would be able to remove the rack if needed

[geezer]

I have seen a few cnc tables were there just pop riveted at the ends with aluminum rivets and a thin bead of glue underneath since all the pressure is pushing down on rack could use jb weld but never would be able to remove the rack if needed

I think you have nailed the issue,,,when you think about it ,,the stresses are forcing the rails from end to end ,,, a rivet at each end should take the strain and doublesided tapes function is just to hold the rack in position....I can see this more clearly now...thanks

[Rodsmachineshop]

this is the one i going to buy almost there with the funds its under 2000 and you get the computer and every thing just have to build the base i like the tracks facing down so you don't get spatter in the tracks and dirt this is the 4x4 but a couple of hundred more its a 4x8 like this to since all the cables are shielded computer lan cords with nice connections

[Rodsmachineshop]

is it bowed down or up

[sportbike]

this is the one i going to buy almost there with the funds its under 2000 and you get the computer and every thing just have to build the base i like the tracks facing down so you don't get spatter in the tracks and dirt this is the 4x4 but a couple of hundred more its a 4x8 like this to since all the cables are shielded computer lan cords with nice connections

Who sells that kit? It looks a little lightweight, but probably fine for a plasma.

[Rodsmachineshop]

http://shop.gearheadcnc.com/ not my fault they push longevity welders lol

[Rodsmachineshop]

i would rather have aluminum than steel since there's no real weight