Widening portable gantry advice

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A good customer of mine has this portable gantry they need widened.  Their current lift table took a crap and they are getting a new one which is 8" wider.  What are your thought on cutting and welding in an 8" section to the top tube?  The top piece is 2"x2"x.25".  I was thinking of making the cut to the right of the hoist and then having room to weld reinforcing flat bar along both sides of the addition stopping before their "hoist mounts".  This thing usually lifts engines into riding lawn mowers and that sort of thing.  Not used for super heavy lifting but I'd still like to make sure the modification is at least as strong as the original configuration.  And also if they were to have some knucklehead use it for more than it was intended I'd like for something other than my modification to break first.  From the looks of the cheese-ball hoist and mount I'd say that's the week point now.   I mig weld often and don't question my welds but rather if the technique of cutting in a section here is sound.  It seems lately I have less trust in my abilities to factor in wall thickness, bracing, etc. rather than actually laying down a solid bead.  I'm sure this question is below what most of you guys do on a daily basis but my shop usually deals with things of a different nature so your advice would be greatly appreciated.
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Reply:2nd on adding new top just as fast and a lot safer, less liability
Reply:6 inches is not going to change the rating on that- what ever it is. The straps holding that motor winch on will fail long before the top tube does.
Reply:Originally Posted by kize6 inches is not going to change the rating on that- what ever it is. The straps holding that motor winch on will fail long before the top tube does.
Reply:You could cut top tube where gusset meets tube, lay longer tube on top and weld.Why not make it two foot longer so you have some "wiggle room".
Reply:Replace the WHOLE TOP TUBE.........That's the way a professional would do it....... Replacing a little top section (6") is a sign of a hack artist, not a professional.......
Reply:My first gut response to the shop guys was to cut the top off and replace.  I guess I should have trusted my gut.  It's just the light duty nature of this unit made me think adding in 6" of material would be sufficient.  I guess sufficient versus recommended are two different things and I should always error on the side of recommended.------------------------------Miller 211 (transformer)Miller Maxstar 150STLLincoln Precision Tig 225Hobart Handler 135Miller 375 X-treme plasma
Reply:IF, if I didn't want to put my "jiffy" in "park", and wanted to do it in a jiffy, I would cut the top tubing at a 45 degree angle, right at the end of the 45 degree braces. Your cut line on the top tubing would follow the line of the angle brace. Weld your longer tubing across the top. Then, make unto thee some VEEERY nice corner gussets, (two required, and they will be bent to match the angle between the new top tube and the existing tubing with the open ends), and use them to both gusset and cap the affair at the same time. If you do it neatly, people will think you built it that way from the beginning, and will admire your engineering abilities, and will build theirs the same way!!
Reply:Originally Posted by villageblacksmithIF, if I didn't want to put my "jiffy" in "park", and wanted to do it in a jiffy, I would cut the top tubing at a 45 degree angle, right at the end of the 45 degree braces. Your cut line on the top tubing would follow the line of the angle brace. Weld your longer tubing across the top. Then, make unto thee some VEEERY nice corner gussets, (two required, and they will be bent to match the angle between the new top tube and the existing tubing with the open ends), and use them to both gusset and cap the affair at the same time. If you do it neatly, people will think you built it that way from the beginning, and will admire your engineering abilities, and will build theirs the same way!!
Reply:Yep, you got it!! Good for you! Of course, you won't want to leave the ends of the gussets square. Either gently round them, or put a small 45 on each corner.
Reply:And you will wish to extend the gusset, as shown in your drawing, at least an inch down past the horizontal weld seam of the original tubing.
Reply:What thickness would you go with on the gusset?  1/8"? 3/16"?------------------------------Miller 211 (transformer)Miller Maxstar 150STLLincoln Precision Tig 225Hobart Handler 135Miller 375 X-treme plasma
Reply:Originally Posted by JiffyParkWhat thickness would you go with on the gusset?  1/8"? 3/16"?
Reply:Probably 3/16 or even 1/4 depending on what I had in the short steel rack.
Reply:Replace the top with an "I" beam and run it out past the legs 1 1/2'  Put your kick braces out there.  Then put a trolly on the beam and enjoy the usable travel.Dan D.Manipulator Of Metal
Reply:Dan D makes a valid point. I did that to mine a few years back. All one would have to do in this case is to cut top tubing like was mentioned, then flip the resulting frames inside out, and you would end up with the kick braces to the outside. Then set i-beam on top and proceed as outlined above.
Reply:I'd cut it in half and weld a new top piece the full width on top. Put a bit of RHS in the gap left as filler if you need it to to mount the winch.
Reply:Originally Posted by DanD78Replace the top with an "I" beam and run it out past the legs 1 1/2'  Put your kick braces out there.  Then put a trolly on the beam and enjoy the usable travel.Dan D.