Millermatic 252 exo cart

[kb0thn]

I got a shiny new Millermatic 252. It comes with two dinky handles on the front and nothing to hang your cords on. The 252 is replacing a Millermatic 180 that I had a on a cart with lots of drawers...which I really liked. So my plan for this machine is to get some storage. Anything beyond that is bonus.

After much beard scratching and staring at the machine, I decided to replace the tank bracket and mount to it and the running gear axle. I designed a replacement tank bracket with recessed for square tubing. The bracket is laser cut 10 ga stainless 304 which I had laser cut and then I formed on my CNC press brake.


The vertical members are 1-1/2" x 11 ga square stainless 304. I had to notch one leg to clear the power and gas inputs. And the other leg a hole so I could replace a short factory screw with a longer screw through the tube.


Because the machine has a massive side cover that flips up, I had to make the shelf support clear that. It's quite a ways up there. But with the big diagonal gussets, the thing is pretty solid.

[kb0thn]

The top shelf has plenty of room to put my Hypertherm plasma cutter on it. I like long power cords so I can drag the machine around the shop. Normally I replace the factory power cord on the machine with a 30' cord made from 6 AWG SOOW cord. I this case I decided to make double outlets on the cart and then just plug in both unmodified machines. So I designed another formed stainless piece that tucks into the vertical tubes and has cutouts to accommodated raised industrial covers as normally used on 4" square boxes. Splitting the 6 AWG power to both outlets stumped me for a bit. I don't like wire nuts, so I was heading towards expensive Polaris connectors. But then I remembered c-taps and I even had them on hand and the proper crimper for them. They are a copper c that splices a 6 AWG tap wire on to a 6 AWG run wire. I used three of them. You can see the c-tap on the green ground wire. The two hot leads have the same thing, just insulated with some heat shrink. After the photo was taken, I re-identified the white wire as red to indicate that it isn't a neutral.


Below the outlet block there is a wire mesh cord grip to provide extra pull out protection for the long power cord. And there is a spot to keep a wrench handy for changing bottles.


And the result is two rock solid NEMA 6-50 receptacles with 30 feet of cord.

[kb0thn]

To make room for the cover to open, I put drawer slides for a side opening drawer. I haven't finished designing that drawer yet. I am thinking that it will actually be two or three drawers. The whole stack will slide out sideways and then maybe from there drawers can slide out the front. I have more parts going to the laser cutter in a few days, so will do this pretty soon. Drawer is 24" wide and 12" deep. Drawer slides are rated for 270 lbs.


Front view:


Back view:


Besides the drawers, I need to cut the top for the plasma to sit on. And add some tie down straps for the plasma. Then I need to actually weld it up. Right now it is just tacked. The big gussets make it really strong. I can sit on the top front end. But none-the-less I will probably completely overweld it and then get mad at myself for crummy looking out of position TIG welds. But that's how I am.

Right now it seems nice and stable. We'll see how it is with another 150 lbs of drawer and plasma and what-not on it.

[Deadsquiggles]

Nice cart mods. I like the idea of the outlets on the cart with just the single 30ft power cord to plug in. Are there any worries of drawing too many amps and tripping a breaker with that setup if you have your plasma cutter and 252 on at the same time?

[kb0thn]

Nice cart mods. I like the idea of the outlets on the cart with just the single 30ft power cord to plug in. Are there any worries of drawing too many amps and tripping a breaker with that setup if you have your plasma cutter and 252 on at the same time?

No. The 6 AWG cord is rated for 50 amps and the wall outlets have 50 amp circuit breakers on them. So no matter if it comes from one machine or two, the most the wiring will ever have to carry is 50 amps. You are right though, with both machines running I could trip the circuit breaker. This is at my home shop and it isn't likely that I'll be welding and running the plasma cutter at the same time. Although I do have a guy that works for me who will weld with two MIG guns at the same time. The hand eye coordination on that guy is something else.

[kb0thn]

The post disappeared, but somebody asked for a press brake video:


This isn't a part for this cart. And it is one of my employees, not me. But here is my press brake bending 1/4" stainless 304. We are working off the end of the brake so we can form a tricky little part. It is an Accurpress 7606. 6ft bed and 60 tons. It's got Accurpress' basic CNC control so we can control back gauge location and bend depth. Basically to set the machine we load the dies and figure out how far down the punch goes to make the desired angle. Get it dialed in and you can make very precise and repeatable bends. It is relatively easy to make very closely fitting parts. I design everything in Solidworks on the computer and have my flat parts laser cut. By carefully bending them I have almost no gaps to fill.

[billwood437]

Great shot of the plug wiring. I was looking to do the same thing for my Mig/ Tig cart. I was unsure of how to do the wiring for the boxes. I too will only be running 1 machine at a time but switching those plugs is a pia.
Thanks.

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[kb0thn]

Great shot of the plug wiring. I was looking to do the same thing for my Mig/ Tig cart. I was unsure of how to do the wiring for the boxes. I too will only be running 1 machine at a time but switching those plugs is a pia.

The manufacturer and part number for the crimp is Panduit CTAP4-6-L. You can get them from Digi-Key in single piece quantities with their part number 298-14350-ND. You do need a 5/8" die or BG designated crimper to properly crimp them. Electricians probably have a 5/8" fixed die on their manual crimpers they use for overhead service wiring. This is the sort of crimper I have:
https://www.ebay.com/itm/Kearney-5-8...EAAOSw8G1d5C0j

I think there are wire nuts that can do three 6 AWG wires as well. But like I said, I dislike wire nuts. If I can't go with a compression fitting like this or a lug, I'll typically go right to big power distribution terminal blocks.

[kb0thn]

Got some drawers designed and cut. To make room for the side hood on the welder to open, the drawer stack slides out the side. I have a drawer on top that has really tall front and back, which make up the sides for two drawers that slide out the front.


I always forget that forming pans on a press brake is a little tricky. Ended up scrapping one of the two bottom drawers by bending it wrong. So will try again next week. Hopefully this weekend I can sneak out to the shop and get the front opening drawer slides and one of the drawers installed.

[PDXsparky]

Nice looking cart.

I think there are wire nuts that can do three 6 AWG wires as well. But like I said, I dislike wire nuts. If I can't go with a compression fitting like this or a lug, I'll typically go right to big power distribution terminal blocks.

Having 30+ years of experience as a journeyman electrician, I agree. Wire nuts are fine for 10 AWG and smaller. Even then, a mechanically crimped on lug is better there too.

[kb0thn]

After a very busy summer at work, I am trying to get some personal projects clogging my home shop out of the way. Yesterday morning and this morning before work, I "finished" the cart. I've have the formed drawers sitting for months. Just needed to weld them, add drawer slides, and assemble the whole thing.

Welding the drawers. Just little welds along the seams. Don't need to over weld it.


Welding cheap Amazon drawer slides onto the side panels. Using the 123 blocks for spacing them 1" from bottom edge and 3" inside to inside spacing between.


Slides to drawers. No preparation. Just melt the zinc plated steel drawer slide into the 304SS drawer. Good enough. Had a fan blowing at my head to keep the nasty zinc smell of death away.

[kb0thn]

Plenty of weld. We aren't building a rocket ship here.


Attached into cross slides.


Drawers installed.

[kb0thn]

Front opening drawers for frequently accessed stuff.


Whole chest of drawers slides to the right so the panel on the welder can be opened.


Drawer on top sized to fit two rolls of wire.


On to the next project!

[Munkul]

That's very cool and very nicely done. I think I will copy the start of your idea - the tube frame loop at high level with the cable holders. I'm sick of wrapping up MIG cables and that way I'd get away with 2 loose loops for the gun, and keep it away from the rest of the machine (currently I drape the cables around the front of the machine and it really annoys me)

[acourtjester]

Great looking cart, on mine I have both Mig and Tig wired into a box with one cable going to the wall plug. I would have put the welder on the top, mine the Tig is on top easier to see and adjust setting. Different strokes thing.

[N2 Welding]

Looks good. I’m sure it is nice having a break to bend the drawers. Did you CNC plasma cut out the sheets?

[Lis2323]

(currently I drape the cables around the front of the machine and it really annoys me)

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[Louie1961]

Not to be negative, but that is starting to look top heavy/tippy?

[Lis2323]

Not to be negative, but that is starting to look top heavy/tippy?

Judging by the quality of work and the OP’s excellent attention to detail I have no doubt it would be indeed stable.. Especially based on a relatively heavy machine

However the design itself leads to the illusion of instability and imbalance. JMHO tho….

Very nice work none the less.


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[kb0thn]

Looks good. I’m sure it is nice having a break to bend the drawers. Did you CNC plasma cut out the sheets?

The CNC press brake is awesome. It's not quite as simple as it looks to both setup the machine or design the parts to be formable. But once you have those things figured out, making lots of something is really easy.

The 16 gauge stainless is laser cut by an outside vendor. We make a lot of products from 16 gauge stainless, so I can "sneak in" a few shop projects.

Not to be negative, but that is starting to look top heavy/tippy?

It's quite stable. Machine weighs 205 lbs according to Miller. Tank adds more weight down low. 30 lb spool of wire adds more. I just walked out and tried tipping it over on its side. 215 lb me would struggle to do it. Getting it up on one side of wheels is about equivalent to tilting a refrigerator back on a hand truck. Possible, but pretty hard. The shop I use the machine in has perfectly smooth concrete with no expansion joints. No concerns. But I wouldn't be concerned about it on a crappy concrete floor or even a dirt floor. It's solid.

[kb0thn]

Great looking cart, on mine I have both Mig and Tig wired into a box with one cable going to the wall plug. I would have put the welder on the top, mine the Tig is on top easier to see and adjust setting. Different strokes thing.

The "cart" is really just the upper frame added to an off the shelf machine. So it already was welder on bottom and had the wheels and everything. This welder is a beast at a couple hundred pounds weight, too.