Pedestal Stand for HF Pickup Truck Crane

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This is a project for myself to help me lift things in and out of my pickup truck bed as well as lift things off the driveway up over a wood retaining wall and onto the adjacent front lawn (driveway slopes down below grade).I bought a Harbor Freight pickup truck jib crane with the cable winch.  I designed and built and a 5ft tall pedestal for the jib crane to mount on top of.  This way I don't have to mount it to the truck for 80% of the jobs I need it for and so that I can lift things higher in order to get over the retaining wall (8ft total at point of lift).Here are the machine settings and pictures of the pedestal welds.Miller Millermatic 210Voltage Knob: 3Wire Speed % Knob: 4075% Ar / 25% CO2 25cfh.035 ER70S-6All steel is hot rolled with mill scale ground off where welds were to be made.  Dimensions are in inches.  Diagonal legs are 4x4x.12 (11ga) A500 square tube.  What I call the Wall Plate (isosceles trapezoid shaped plate parallel to plane of legs, perpendicular to the ground) is 1/4" thick A36 plate.  What I call the Top Plate (12" x 12" square plate with bolt holes to match HF truck crane on top, parallel to the ground) is 1/2" thick A36 plate.  Simple plates to cap the bottom of the legs and serve as feet are 1/4" thick A36 plate.I finished the welding yesterday.  I still have to drill four holes in the wall plate to be clearance holes for 1/2" lag bolts.  The 1/2" lag bolts will secure the wall plate to the wood retaining wall (6x6 pressure treated lumber with rebar that was put in during construction in 1990/1991).  I have future plans to make female threaded anchors in the retaining wall so the pedestal is more easily installed and removed (the crane is meant to be setup and torn down for each job - it won't get used frequently).I need to wipe it down, clean it up and primer the areas where mill scale was removed and rust wants to form.  I would like to just use a clear coat primer (something I have used in the recent past for protecting freshly ground steel from humidity for an inside the house furniture project).  Would that be a mistake?  I'm undecided on painting it or not beyond spraying the bare areas with the clear coat primer.  If the whole thing was to be painted one color, would I need to remove all the mill scale off everything?I'm posting these pictures before final clean up and primer in case you guys spot something that I overlooked in the build on the welding side.  I'm planning to load test everything in safe controlled conditions (i.e. lift a known load 1" off the ground) before considering it good to go for its intended use.  If I made a big mistake in how I welded the 1/2" thick Top Plate to the 11ga square tube, I woud like to know so I can fix it now before doing anything further.  Thanks for looking.(pictures on next post)
Reply:1st - solidworks model (stand was load tested in simulation and passed with large margin - but the simulation assumes perfect welding)2nd - front of 1/4" wall plate to side of 4x4x.12 square tube fillet3rd - bottom of 1/2" top plate to side of 4x4x.12 square tube fillet4th - bottom of 1/2" top plate to back side of 4x4x.12 square tube fillet Attached Images
Reply:1st - back of 1/4" wall plate to side of 4x4x.12 square tube bevel2nd - bottom of 4x4x.12 square tube to 1/4" thk foot plates 3rd - rear quarter overall view (if the front of the pedestal is 12 o'lock, perspective for this shot is 4:30) Attached Images
Reply:I would add a 3rd leg so the crane doesnt pull on the retaining wall with full load....Of all the things I lost I miss my mind the most...I know just enough about everything to be dangerous......You cant cure stupid..only kill it...
Reply:I second the third leg idea. because your driveway is below grade I understand that it can't stick out far, but even just a little will help tramendiously. with the boom out far enough to 1 get stuff out of the truck, and 2 get it up high enough to get onto the raised lawn, you're going to have a lot of lateral force on those lag bolts.I would also add wall plates to the bottom of the two legs you had, for the same reason. when you're lifting over the lawn the weight and leverage will be pulling the legs away from the wall.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:Wall plates at the bottom of the legs is a good idea and good catch.  I should have caught that during design.  I focused in too much on just the first part of the lift operation.  Thank you ThorsHammer.I hear you on the third leg.  I spent most of my time in this area.  The 1/2 lags are conservatively rated for a large amount of tensile force even in soft wood.  I don't the numbers I did on hand, but I did run them with a safety margin and used the most  conservative pull out strength numbers.  On paper it should be fine with plenty of margin.  This assumes the retaining wall 6x6s are in perfect health and are not rotten at all.  I mentioned the construction date because their state of good/bad/rotten is something I don't know yet.  I'm planning to drill, check and test this.  All of this applies to the lifting off the driveway case.  As you guys said, it needs wall plates at the bottom to do the same job when the load is raised and swung over the retaining wall and above the lawn.With no third leg, I can back the pickup truck up closer to the crane (driveway is shaped such that the truck will be perpendicular to the front of the pedestandal stand - the driver's side of the truck will be parallel and facing the pedestal stand's wall plate), keep the jib arm extension shortest and minimize the tipping/overturning moment caused by the load.  If I can't do this safely, then it's moot and I have to do a third leg or redesign.  If I can do it with no third leg and good use of lags, it will make this crane much more useful to me.There were two other reasons for no third leg I considered.  One was to keep the structure "flat" in design/shape so I could store it more easily and the other was to keep the weight down so that I could still pick the pedestal base up and move it myself for one man operation.
Reply:I'd use a folding/colapsing third leg. pivot point at the top and telescopic foot to make it easier to store. If the pivot point was a quick release pin it would keep weight down still. and can be added or removed when needed, load dependent.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger