Precision Plasma CNC table build

[Tech Tim]

I've been playing with this build for a few months now and figured it was time to start posting up pics.

Specs:
4x5 Home built table set-up
Precision Plasma LLC 3x4 gantry kit - www.precisionplasmallc.com
CandCNC Blade Runner 4 electronics package - www.candcnc.com
Mach3 software package - www.machsupport.com


We started with a Precision Plasma LLC gantry kit (www.precisionplasmallc.com). We didn't want a full 4x8 table, too big, didn't want a 2x2 table, too small, so Ron at Precision Plasma showed us plans for his 3x4 table.

The table actually comes out to 4’x 5’ in size and the gantry cuts out to about 50" wide and 40" in depth; that will allow us to easily run 4x4 sheets on the table, so we can order 4x8 sheets of plate and cut them in half for easy storage and easy handling.

This is what the table looks like:

[Tech Tim]

Here are the plans for the individual components:

[Todd W]

Looks good.

Are you done? Any test cuts?

[Tech Tim]

We do have it up and running, will post up pics of the cut later on in the build.

[Tech Tim]

List of materials:

2"x 2"x.120" Square tubing
Q 4 - 56"
Q 2 - 48"
Q 4 - 44"
Q 4 - 7.5"
Q 4 - 26"
90* cut both ends

2.5"x 2.5"x 3/16" Angle
Q 2 - 49"
Q 2 - 61"
45* at both ends measurement to tips

1.5"x 1.5: x .120" Square tubing
Q 1 - 36"
Q 1 - 20"
45* at one end- measured to long tip

2" x 1/8" Flat bar
Qty 10 - 48"
Cut at 90* both ends

1.5"x 1.5"x 1/8" Angle
Qty 2 - 48"
Cut at 90* both ends

[Tech Tim]

Edit: This is somewhat of a step-by-step build up and has some basic fab tips for the newbie fabricator. If it isn't hard-core enough for you feel free to move along and start your own build.

Clean the scale off your tubes at all weld locations.

You want to learn to weld better? Start with good metal prep and you'll be surprised at how much better your welds come out.

Make sure your welder is in good condition too, if you are running an older MIG, spend $50.00 and get a new liner for your whip and some new tips. We're running .030 wire through our Miller 211 Auto-set MIG machine on the 110 plug.

We used .120" wall for all our tubing, it's what we had on hand. Ron at Precision Plasma said we could go thinner if we wanted, but we like the idea of extra beef.

[Tech Tim]

We started out welding the side rails for the table top using a carpenter's square and a Speedi-square to make sure everything is perfect.

Once tacked together, we double checked for square and started welding. We welded the inside corners to lock the rail in place, we'll finish welding the rails after we build the other side.

[Tech Tim]

Once we had one side welded solid, we laid the other side out on top and clamped them all in place to keep both side exact.

[Tech Tim]

Once both side rails were welded at the inside joints it was time to weld the sides. So we pulled out the Miller Diversion 165 and TIG'd up the side joints. One benefit this gave us was a nice flat junction so when we add the cross rails we didn't need to grind down any welds, just a quick hit with a sanding disc to knock down any high spots.

[Tech Tim]

Of course Trapper Tom (85ToyotaTom) had to join in on the TIG'ing action. I think he wanted to show me up a little....

[Tech Tim]

We laid out some lengths of 4x4 tubing to act as a temp jig base and started laying out the side rails and cross beams.

Then a couple tacky-tackies to hold it together and check it once more. I can't stress how important it is to make sure everything is straight and true.

Once it was true, we started welding in all junctions. We took our time, jumped from corner to corner with each weld to keep the heat warpage to a minimum.

[Tech Tim]

With the table top welded up it was time to start assembling the gantry rails.

We set the Y-axis rails onto the side rails, leveled them up by eye and clamped them in place.

Here is the trick for making sure that your parts are square is to do a cross or X measurement. Start by measuring from the tip of the rails 45* caddy-corner across to the other tip, then caddy-corner to the other two tips so you have both directions and compare the measurements. We were off by about a 1/4", so it was a couple little taps with a hammer until we had those measurements identical.

[Tech Tim]

With the Y-axis gantry rails solidly located, it was time to transfer punch the holes through each rail into the 2x2 top rails.

We then drilled them out to a #7 drill bit and tapped them to 1/4" - 20 thread.

The pics doesn't show it, but we did just the end holes first, bolted in the rails, then transfer punched all the holes along the rail, then drilled and tapped them.

Last step was to run a sanding disc across the top rails to smooth out any raised burs.

[Tech Tim]

The Y-axis gantry rails are then placed back on the top of the table rails and tightened finger tight. Tommy then measures and remeasures as before to square up the Y-axis gantry rails and then tightens up the rails a bit tighter, still not torquing the bolts yet. We've also only installed 3 screws per side; one at each end and one in the middle.

Harrietta, our resident pest control officer, watches closely over Tommy; if he messes up, she will handle the situ.

[Tech Tim]

It was now time to assemble the X-axis gantry and align the Y-axis rails.

The end pieces are cut to slide down over each end of the X-axis gantry and is bolted up with the supplied hardware.

Check out the close up of the fit between the V-rails and the guide wheels. The guide wheels need to travel back and forth across the V-rails smoothly without binding.

Once we had the X-axis gantry on the Y-axis rails, we rolled it back and forth slowly checking for binding. If we did the cross-measure accurately we should be very close and we were. We found a little bit of binding and just tapped on the Y-axis gantry rails with a mallet a little until it was perfectly and we were able to smoothly roll the X-axis gantry from one end to the other of the Y-axis gantry rails.

Once it was rolling smoothly, we tightened the 6 bolts we had retaining the Y-axis rails tight, followed by adding the rest of the retaining bolts and tightening them down.

[Tech Tim]

With the Y-axis rails aligned and secured, we pulled off one of the end pieces and slide the Z-axis onto the X-axis gantry. The end piece was bolted back up to the X-axis gantry and then once more we rolled the X-axis gantry back and forth on the Y-axis rails to make sure everything was lined up.

[Tech Tim]

It was now time to assemble the base for the table. We again laid out a couple lengths of rectangle tubing to use as a temp jig to keep everything in line.

We then started laying out the pieces we had cut for the base, squared them up with our carpenter's square and the much used speedy-square and started tacking tubes together.

One little trick we use is to cut the 90* corner of our speedy-square so it will clear any weld beads on an inside corner.

[Tech Tim]

After we welded the left and right sides of the base we hit them with the grinder to flatten out any high spots.

We changed our jig up a little bit. We have two pieces of rect. tubing laid out and then laid two more across the first two, this gave us a very square surface to work off of when assembling (not as good as a dedicated jig table, but good enough).

We stood up one of the sides on our temp. jig, squared it up and tacked it in place on one of the jig tubes. Stood the other side up and tacked it to the other jig tube and then used a couple of welder's magnets to hang the cross-beams into place between the sides, square them up both vertically and horizontally and tack into place.

Once the base sub frame was tacked together we used a small ratchet strap to pull it square. After we know it was tacked square, we started laying down the beads, again moving our welds from corner to corner to keep any movement to a minimum.

[Tech Tim]

It was now time to assemble the 2.5" angle pieces to form the top of the base.

We set the angles down on our double stacked temp. jig, squared them up and tacked them together. We then double checked our square by measuring corner to corner like before and laid down beads at each of the outside corners.

[Tech Tim]

The top was flipped upside down on the temp. jig and we welded the bottom side. We gave the edges a bevel so we could sink our welds down into the material; first for strength, second for a flat surface.

After welding and a pass of the sanding wheel, we inverted the base and centered it by measuring the distance between the edges of the top and the vertical tubes of the base. We just kept moving the base structure around until we had even measurements at all 4 corners.

Then it was a simple job to weld the base structure to the bottom of the top made from the 2.5" angle.

[Tech Tim]

Next up was to cut a few rectangle pieces that matched the top of our casters. We got ours from Harbor Freight, but Ron at Precision Plasma will supply them with your kit if you want.

The table was set on the plates, the plates were welded and then the casters installed.

[Tech Tim]

The base was turned up on all fours and all our squaring, checking and re-squaring paid off... it sat on all four casters nice and square.

Just for the practice of welding tight areas, we fired up the Miller DV 165 and TIG'd the joints on the inside of the 2.5" angles.

[Tech Tim]

The gantry top was set into the top of the base structure and it was time for the slats.

We decided to change up the slats a little from what was shown. Ron at Precision Plasma has told us that we could build the real nice ones shown in his plans or we could do a more basic design and then cut the fancier ones out on the plasma table at a later date.

Being cheap (and lazy buggers) it was decided to do the latter and took the two 48" pieces of 1/8" angle, marked them out with lines every four inches. They were then set into place one in the front and rear cross-beams of the gantry table and we stood the 10 - 2"x 1/8" slats on end and welded them into place with 1/2" beads.

[Tech Tim]

Here is what the table looks like before we start getting into the electronics.

[Todd W]

Great thread, detail is amazing