Plasma CNC Table Weld-up

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Here are the front and back sections of the table tacked together. I plan to tack on the side rails and then make a square/level check before final welding. Any suggestions on the final order of welding? I was thinking of doing all of the top welds 1st (looking down from directly above the table). Then from the bottom up and then from the inside out. Maybe with a few minutes in between each pass. Attached ImagesMIG and Plasma
Reply:Weld the but joint sides first. And the fillet last. Run them in opposite directions so the side face us in the pic weld them vertical up and the other side vert down. (or flip it over and eith it upside down weld it vertical up. This will lock it together, and the welds going opposite one another will cool and pull it to help keep it square. A fillet weld will pull more as it cools than the butt weld. So by welding the butt welds first it will lock it in place and the fillet won't be able to pull the joint out of square. This is how I did my Cnc plasma table, and it's square to within a 1/32 of an inch across a 12 foot span. I'm sure others may chime in and say different, as I'm sure there are tons of ways to build it. This is just how I built mine. And it worked for me. I currently have aprox 2500 pounds of steel on the shelf under my table, and it has about 1000 pounds of water in it. The frame and gantry is probably close to 800-900 pounds by it's self. And I have even bumped the table with my truck (backing up to it to unload a sheet of 1/4 inch) and it's one solid structure. Btw who's table are you building?Offering CNC Plasma cutting and welding projects.Follow me on facebook https://www.facebook.com/nobigdeal.fabSupport those that support WW.
Reply:Originally Posted by NoBigDeal FabWeld the but joint sides first. And the fillet last. Run them in opposite directions so the side face us in the pic weld them vertical up and the other side vert down. (or flip it over and eith it upside down weld it vertical up. This will lock it together, and the welds going opposite one another will cool and pull it to help keep it square. A fillet weld will pull more as it cools than the butt weld. So by welding the butt welds first it will lock it in place and the fillet won't be able to pull the joint out of square. This is how I did my Cnc plasma table, and it's square to within a 1/32 of an inch across a 12 foot span. I'm sure others may chime in and say different, as I'm sure there are tons of ways to build it. This is just how I built mine. And it worked for me. I currently have aprox 2500 pounds of steel on the shelf under my table, and it has about 1000 pounds of water in it. The frame and gantry is probably close to 800-900 pounds by it's self. And I have even bumped the table with my truck (backing up to it to unload a sheet of 1/4 inch) and it's one solid structure. Btw who's table are you building?
Reply:Keep in mind, I an not a structural welder. So it may not be the "correct" way but it works.Offering CNC Plasma cutting and welding projects.Follow me on facebook https://www.facebook.com/nobigdeal.fabSupport those that support WW.
Reply:What does the entire table look like? It's hard to tell what's going to happen without the whole design in mind.Ian TannerKawasaki KX450 and many other fine tools
Reply:Originally Posted by fortyonethirtyWhat does the entire table look like? It's hard to tell what's going to happen without the whole design in mind.
Reply:Originally Posted by fortyonethirtyWhat does the entire table look like? It's hard to tell what's going to happen without the whole design in mind.
Reply:Below is the base table less the top rails which I am not going to attach until I have the gantry put together. Attached ImagesMIG and Plasma
Reply:Here are some close-ups of the welds. I think that I did Ok with the filet welds. I struggled with the butt welds a bit, I am just not uniform enough yet when running a pattern. Please feel free to chime in with your thoughts/suggestions. This is the largest project that I have done so far and I felt like I improved from the 1st to the last weld. I wish I had a few more projects under my belt before taking it on, but I really want to get a CNC going. Attached ImagesMIG and Plasma
Reply:good job. think of it this way its only steel and a bit of time. you could always make another one someday. also, you will not know how you ever lived without a cnc plasma once you have one. its probably the coolest toy on my street. and there are some killer racecars on my street........Offering CNC Plasma cutting and welding projects.Follow me on facebook https://www.facebook.com/nobigdeal.fabSupport those that support WW.
Reply:Well, now that you've done some similar joints. You should be able to predict what will happen when you attach the top. I'd go through all the joints with a square and a straight edge, to see exactly how each joint warped. It's usually the T joints that cause the most trouble. A bolted connection will usually avoid the warping.Ian TannerKawasaki KX450 and many other fine tools
Reply:Originally Posted by ★ NoBigDeal Fab ★good job. think of it this way its only steel and a bit of time. you could always make another one someday. also, you will not know how you ever lived without a cnc plasma once you have one. its probably the coolest toy on my street. and there are some killer racecars on my street........
Reply:Originally Posted by fortyonethirtyWell, now that you've done some similar joints. You should be able to predict what will happen when you attach the top. I'd go through all the joints with a square and a straight edge, to see exactly how each joint warped. It's usually the T joints that cause the most trouble. A bolted connection will usually avoid the warping.
Reply:Originally Posted by MoJo1917Thanks, I am really excited about getting it going. I suspect it will be a while before I even receive all of the parts. What table did you build? What do you use it for primarily?
Reply:Originally Posted by MoJo1917What do you mean by "a bolted connection"?
Reply:Originally Posted by ★ NoBigDeal Fab ★My table is a precision plasma HBL gantry with candcnc electronics. It's a 5X10 I cut just about anything on it. I have done artwork, automotive parts, brackets, you name it.
Reply:Originally Posted by fortyonethirtyOn items that need to remain perfectly straight, like the tubes that will support the guide rails, use screws or bolts to fasten them to the table. Also good for items that might need adjustment. To avoid warping these critical parts, don't weld on them at all. You can use angle brackets, or weld base plates to the non critical side of the joint.
Reply:Originally Posted by MoJo1917I found the HDL on their site, not sure if it is the same. Looks like it cuts really cleanly, I hope that I can get close to that.
Reply:I finished fabricating my height adjustment system. I cut out 3/16 inch square pads and then cut holes in the center. Then I welded nuts onto the pads. I am using casters for now, but plan on using a "fixed" system when I start cutting. The 3/16" pads are welded to 1/8" square tubes. I went with .030, 75/25 argon/CO2 at 15 cfh, 20 volts and 235 ipm. Penetration appeared to be good, but the weld profile seems high. I think that 20 volts should be hot enough, should I have gone with less wire speed? The sound/feel seemed pretty good when I was welding them. Attached ImagesMIG and Plasma
Reply:Here are the brackets that I cut out for the y-axis rails. They will allow some adjustability since the holes have a larger diameter than the bolts that will attach the rails. Once I have everything adjusted/working properly I may end up welding the rails on. I used a straight edge and a washer as guides. Attached ImagesMIG and Plasma
Reply:The top y-axis rails are 2"x1/8" and I need to drill and tap quite a few holes for 7/16" bolts. They won't need much torque, but I am a little worried that 1/8" is sort of thin for tapping. Should I go with 2"x3/16"s?MIG and Plasma
Reply:I came across this thread which answers my question:http://weldingweb.com/vbb/showthread.php...%2F8+drill+tapIt has me questioning if 3/16th is thick enough. Since that is what the original plan called for, I may go that route and adjust as needed.MIG and Plasma
Reply:Here is another good thread:http://www.pirate4x4.com/forum/gener...-strength.htmlIan TannerKawasaki KX450 and many other fine tools