Yet another new build

[jjellingson]

I managed to catch this with the first tack weld burning through. Managed to get everything lined up again and tacked. All this is done in about four hours time.

This morning I got after welding this thing up. I do have a little welding time in. I think to myself, this thing is really true. Maybe one of my better jobs for laying out a project. Thinking to myself what the hell am I gonna do with it if it warps to much. Pickup bed dump box=? trash trailer? have to salvage something...

Carefully, I welded here, I welded there, and checked, and welded some more. I had the frame work all welded up and I could lay a straight edge down the top rails and thing looked great. Not even a hint of warping.

Mistake one, keep in mind I only have one top rail. I skip welded the inside tank up. Stopping half way and checking my top rails for warping. Things are really good. Completed the inside welds on the tank and Stuck the straight edge up, I lost .050 in 12 feet, actually the last 36 inches on the extended end.

The final welds are in place on the frame and the tank, a couple of mistakes made, not happy but they are do able. Time to test for leaks.

[jjellingson]

I clean things up a bit and decide to fill the tank up with water and check for leaks. A few moments of rigging, and wa la turn on the water. Actually I was reluctant to do this. Not for fear of leaks. I second guessed myself and thought I had better do this in case of a leak behind one of the uprights. (maybe hard to fix). So I did it. If I can manage to get the pics up for you all to see, you may notice a few things. The tank seems to be leak free. I did install one pick of a (galvanized fitting) that appears to be damp...Damp I say. Why the hell is it so hard to find black pipe these days.
This is as far as I made it this weekend. This post may be longer that normal, I thought I had better produce or someone would start thinking I was talking out my ass. Granted the little woman occasionally asks if she needs to stand behind me to hear better.

Millman, Plain ol Bill, and any one else, lets hear from you.

Millman, I know I can compensate with slotted guide rails for the errors in my ways, what are your thoughts on milling the top of the entire table? Probably more grief than its worth. Just a thought...

[jjellingson]

You all may be wondering what is up with this. I really wanted to weld in the top of the bladder but my sixth sense said wait. Why? I am still thinking on that one. I guess if I need to try and straighten out the top rails, it would be easier if I don't have the extra sheet fighting my attempts at this. My thoughts are that If I had (NOT) welded the side sheets in, this could have been fairly simple. Maybe still is. I could slit the sides and just deal with the top rail. I can weld vertical... okay we are open for discussion hear. I have a 4 by 8 one inch thick table, (smaller than this folks) but I could use this to correct this error. What if I took out the ole plasma bob and slit the sides and heat shrink the top rail? (if I fail) I can surely bend it. I have an ole farmers jack out back. Trick is, control.... something I am not all that use too. Your thoughts will be appreciated.

[Kipper]

Ahhh you're doing great....can I play with your truck?

[millman52]

I wouldn't fool with milling the top of the table. You can most likely shrink the top of the box tube (assuming it's the open end that's down). If all else fails you can shim your rail(s) underneath. Especially that being the non business end of the table.

I'm sure you have straightened I beams etc. that way before & know to let cool completely before shrinking a second spot. Somewhere in my build I have a couple pics of heating some spots on 2 X 6 box tube to counter spot welds along the top.

With plasma, a little vertical rise & fall isn't that bad. Your THC will still keep the torch at the proper distance from material being cut. Parallel with the length on the horizontal is critical.


At any rate being out .050 isn't that bad & I'm sure you can straighten that up when aligning the precision rail(s).

[plain ol Bill]

John that is a really good looking start. I would not worry or fret about any dimensions, dips, warps at this point. Put you bladder top in and weld it up. Back step your welds and move around some in the process. When you need to start getting picky is when you start installing rails. You can always shim where needed. Get one rail straight and that is your work point for the other rail. They need to be parallel. If there is a slight dip don't fret too much. Like Millman said that is what a THC is all about. When you go to put slat holders in pay attention at that point so they are all level.
I see the drain point - do you have the air inlet and outlet in yet? If not put them in right at the bottom of the bladder top. I can fill the top of my table in about 45 seconds using full air pressure. I can also create a gigantic mess of water on my floor if not paying attention (don't ask - OK)

[plain ol Bill]

I see you went with square tubing for your frame. Wow - they don't give that stuff away do they! I considered tubing but the 4" channel iron was a lot cheaper so I went with it. The channel worked out fine really. I made the saddles up in a jig so they were all the same. Nice parking area on the one end.
How are you going to handle sheets? I have overhead beams in my shop and put electric hoists in to handle the sheets using a spreader configuration. It has really worked well for me. Getting too darn old to try to wrestle with heavy sheets anymore.

[jjellingson]

Thanks for the response Bill and Neil, I was just caught off guard with this distortion. I had skip welded the bottom of the tank and thought I had covered all my bases. I should have had the tank bottom and sides bent. Saving a few bucks and a trip to another shop actually will cost me in the long run. I have a couple of ideas on what to do. I am concerned with welding in the bladder, this may compound my problem. I will be keeping an eye on that.

Bill, I will use the service truck crane to load sheets onto the table, maybe later pick up a little used forklift. I am rapidly running out of room inside. I need to rearrange the shop inside to be more user friendly. Yes the square tubing is highly priced, should have followed your lead.

I did get the gearing order in yesterday, costs add up quick. I have yet to order X or Y slides, still open for discussion on this. Seems these are spendy also. In the second part of this post I will be firing a few questions to MIllman about his design.

[jjellingson]

This post is for all the home builders of X and Y rails and slides. If you had to do it over would you use your method again? Please understand I have not read every thread, but several have caught my attention. I may just need to nut up and absorb the cost of linear rails and get over it.

Keeping in mind 5'x10' with and additional 2' for staging the gantry when loading is my problem. If I had built a smaller table I would use the methods I have seen on smaller tables.

Not meaning to single out Millman, but his method seems practical for my application. Seems to have solved some of the problems I know I will be facing.

I seem to be at the point of having to make a decision on this. The good part is, I can design around the problem I have with distortion. I am just trying to limit the amount of re-designing I will need to do.

Open for input folks?

[plain ol Bill]

John I have been VERY happy with my V rail system. As you know I used it on X and Y axis runs and a linear slide for the Z. If I had it all to do over I would do it the same way.

[Dustin407]

John,

I would go with the v rails if i were you. Precision rails is just overkill, there is no cut force on a plasma to the material so you dont need that. You just need something that tracks back and forth for that v-rails are perfect plus alot cheaper than precision. Build looks good so far though, i wouldnt get to critical over the minor things yet. Worry when the motors and rails are bolting on.... Hope all goes well...

Dustin

[millman52]

Since I've been singled out!! The Cold Rolled round/Cold Rolled flat bar rail as a guide has worked without a problem for well over 2 years now. The CRR is held in with 2 rows of 4-40 set screws (apx. 60 of them). This was so I could change easily or rotate to a new surface. Neither have been needed at this point. I would use V rail in place of the CRR if I were doing it again. Not that there is any problem with the CRR, V rail would save several hours of build time. The process I used (A bit of overkill on quantity of set screws in hind sight) to install the round bar is pretty detailed in my build log.

On the flat bar side I'd consider dropping it down the side or on the bottom to help protect it a bit more. It hasn't been damaged on the top as it is, but I do have to take care not to thrash it. I always keep a bench broom handy to dust it off between sheets of material.