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Hi Tiny, I agree with Nat, your hanger spacing is wrong. Look on Dexter website thru there lit section and they will have the spec's for the spacing for different axle/spring combinations. The drawing will show the correct weld placement for the hangers. A few thoughts; You welds appear to be thin on the leg of the weld. The leg should be as wide as the thinnest member. Example: A joint 1/4" x 4" x 6" with a butt weld 3/16" 3" x 5" intersectng tube, then the weld leg would be 3/16". You don't show any frame support gussets at the 90º corners (out of the picture ?). Although a tube butt joint is a strong design, over time this joint will become weak. A 45º gusset will add great strength to the joint. Gusset leg length would be equal to member flange width. Example: Using 3" x 6" x 1/4" tube then the gusset leg should equal 3" x 3" x 45º. I like to notch the 90º cornner off about 1/2" as this lets the gusset fit around the fillet weld. A frame should be a box around the axle area. This is a very high stress point of the frame as it takes the load weight as well as road loading forces. Most DOT inspections will require multiple member thickness at the spring hangers. I haven't looked up the code but normally they want to see a piece of angle iron equal to the frame flange width with a continous span thru the spring hangers. Example: A frame made 3" x 6" tube with a spring hanger span of 80" from front hanger to back hanger, would require a piece of angle iron 3" x 3" x 1/4" by 86" long to be skip welded along the length to the frame then the spring hangers would be attached to the bottom of the 3" angle iron. Most structual joints require a bearing plate (the 3" angle iron) for joints tranfering load weight as this greatly reduces joint stress of the hanger mount by distributing that stress over a larger area (helps keep the frame from cracking). Typical skip welding design is the weld leg equal to the thinnest member, minimum 1-1/2" long and spaced at twice the members width. Example; 3" x 3" x 1/4" angle would be skip welded with a 1/4" leg, 1-1/2" long, every 6". Why 1-1/2 long"? We allow for 2 rod diameters of cold lapp weld for each end so our effective weld length is 1" long for stick electrodes. Mig we allow for 3/8" cold lapp. T_Bone
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