3D Corner Jig (Adjustable)

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This is my latest project. A 3D Adjustable corner jig.I made it on to a sheet of 3/8 plate with the corner cut off for access to weld. The jig is set at exactly 90 degree.The upright brackets are for clamping the vertical pieces (legs for coffee table in my case) to the bottom piece.I made the upright bracket adjustable so that if I want to set the leg of the coffee table back 5mm or so, I can. (Or just use a smaller diameter square tube for the legs)I can get about 15mm adjustment if needed.Ignore the quality of my welds, as I am still learning, but it was also covered in so many clamps in the making stage that I could hardly get my MIG gun in there, which made the welds very 'So So'. (anyway, it it holding together even if the welds are not pretty)The pieces of steel in there are just for the photo shoot. Normally I would mitre at 45 these pieces. The whole rig works a treat. First I mitre my two base pieces and clamp in position in the jig. I tack weld all around as I have full access. Then I do a bit more solid weld on the top of the mitre, underneath where the upright piece sits. Then I position the upright, clamp tight before tack welding in place.Because I adjust all the fences and lock in position before I start the job, there is NO need to check measurements after clamping to the jig.Once the whole thing is tacked, then I can complete with a full weld around the entire joint on all sides, as there is 100% access.I made this jig up as I intend to make coffee tables and sell on weekend markets, so I anticipate I will be making quite a few, and did not want to spend all my time measuring, adjusting, re-measuring, clamping ETC.....It works well for me.
Reply:Another good idea. Keep 'em coming. 9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:The welds will get better if you want them to get better.  You know what I mean.  I faced the same thing when I started.Main thing is, you're doing, and not just talking.Ya caught the bug!!!  No gettin' rid of it now"Any day above ground is a good day"http://www.farmersamm.com/
Reply:A good time saving device, well worth taking the trouble to construct.
Reply:Good looking jig.I'd think about having the open tube on the top of the leg (if it gets covered with a top of some sort).  If you intend to weld on "end caps" using your current setup,  shorten the tube length so the cap doesn't protrude beyond the opposite tube.At any rate, I'd definitely close up the tubes, tiny hands get in there and an injury could occur.Good Luck
Reply:Originally Posted by eyspyThe pieces of steel in there are just for the photo shoot. Normally I would mitre at 45 these pieces.
Reply:Great Idea, now just make three more so you can " jig up " your whole table and just weld away.
Reply:Originally Posted by partagasGreat Idea, now just make three more so you can " jig up " your whole table and just weld away.
Reply:Originally Posted by eyspyI thought of that.  Then I thought, 'man OH man' it would like like some futuristic monster from space ! My table sizes will be varying sizes, so that idea won't work.
Reply:Originally Posted by partagasThe jig you have now is just a what 6X6 piece.  So four of those are not going to limit the size or shape of your table.  Since they are all movable.  I did not mean to make them fixed as if part of your welding table.
Reply:I apologize up front for this but I can't help my self.First cool idea.Second way too Rube Goldberg.  The device you spent many hours and some money building, can be replaces with 2 pieces of angle or flat stock and 4 vice grip model 11r's. total investment $70.00 if you have no clamps on hand. I have traveled down the road you are on and it leads to a fixture that is cumbersome to use. Is hard to keep true and yields a lesser finished product. I have built many thousands of tube frame structures. And the one absolute constant, no mater how well you design the fixture, the welding of the tube is going to pull it out of square. Be the welding finished in the fixture and allowed to cool to ambient or only used for tacking the weldment is going to need to be trued, and a compromise will have to accepted as to what side of the cube will not be true. All welds shrink as they cool, that shrinking pulls the adjacent metal with it. As thin walled tubing has little mass to resist the pull it moves the most. Easy way to show your self this pulling is to make up a simple inverted "T" joint with your tube, using no clamps make a fillet weld while holding onto the vertical member.   I would bet that I could use my way and you or any one use their fixture, my way will at lease equal if not beat their time and quality.   No mater how well the material is cut or fixtured the weld shrinking will have an effect. The best thing to learn is what direction to weld and where to start.  Good Luck and please know I am not bashing you just passing along information Attached Images
Reply:Fat Bastard.I take all advice on board, I am learning and if I didn't listen like a stubborn mule I would never learn, so no offence taken.It only took me about 3 - 4 hours to make out of scrap which cost me no money, so no loss there.I hear what you are saying about the heat as well. If I clamp the tube in my jig really tight, and leave clamped till it is completely cooled, will this stop the movement caused by heat ??
Reply:Eyspy:No it won't. The order of your tacks, welds and weld direction are more important. And I have no idea what that order is.  All welds shrink, and I hate it. I still think it's a useful corner jig. Fat Bastard:Those facts took me forever to figure out, as a hobbiest. Thanks for the jig pics.Last edited by Craig in Denver; 03-25-2009 at 12:46 AM.9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Originally Posted by eyspyFat Bastard.I take all advice on board, I am learning and if I didn't listen like a stubborn mule I would never learn, so no offence taken.It only took me about 3 - 4 hours to make out of scrap which cost me no money, so no loss there.I hear what you are saying about the heat as well. If I clamp the tube in my jig really tight, and leave clamped till it is completely cooled, will this stop the movement caused by heat ??
Reply:Eyespy, He's right........It's all about the heat and how it affects the metal"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Hmmmmm....... I must have just fluked upon the right sequence, because since my last post I went out and made a coffee table frame using this jig (will post up pics soon).I made it out of 40 mm box tube 1200mm long x 600 mm wide with 420 mm legs.I used my jig and clamped in place tightly. I then proceeded to tack weld each corner, and then completed the welds on each corner before cooling and un clamping and proceeding to the next corner.Once the top was  made I put each corner back in the clamp and repeated the procedure for each leg.My approach was to weld one side of the tube, then weld the opposite side.When the whole thing was assembled, I placed it on the floor and measure the distance between the legs just underneath the top, then right down at floor level. A blind man would be hard pressed to pick the difference, it was that close to being perfect.This may have been pure luck, my jig, my method of attack on the welds, or a combination of all the above ???  I don't really care to much as I am happy as a 'Pig in Poo' with my results. I will keep my fingers crossed that all the rest turn out the same. I hope so, because this one is spot on !
Reply:Originally Posted by Craig in DenverPaweldor: you missed this.
Reply:Congratulations Eyspy