The horizontal cross bar is a rectangular tubing piece, 1/8" thick,
2x4 in cross section. I can, obviously, change the hooks as the situation requires, and I do not believe that the hook that I have pictured, would be good for 5,000 lbs.
Now I began to have some doubts, maybe just being overly cautious.
The question I have concerns the integrity of the weldment. Would you say that the above design, could be used to lift 5,000 lbs. Yes, no, or maybe? What about the likelihood of the rectangular tubing buckling under load?
The welds connecting the lifting eye, to the rectangular tubing, are triple welds with 7018. They go almost to the edge of the 2x4.
Add a pair of right triangles (points @fork , short edge butt welded to your lug) to that unit and be sure . As you have it the sidewalls of the tube are in compression and it's possible for them to buckle . The triangles will be in tension ... hmm , cut the points off so the verticle edge of the fork pieces will meet a verticle end the same height . I suck at ascii art ... or I'd try to illustrate what I mean .
It's probably good. I like the ultra simple plate style lifting hook adapters where it's just a piece of say 1/2" plate with openings cut for the forks, a lifting handle hole and a keyhole opening to put the lifting chain through. No welds involved to worry about at all.
I would not trust 1/8" to hold 5K, you have disability and life insurance right. The 1/2" steel plate another poster mentioned is a much better solution. How about a short piece of wide flange I beam for the cross member.
Thanks guys. SOmeone else also told me the same thing. I think that whatever I may be lifting, will be worth more than what a proper adaptor costs, and also, the life and health is worth even more. I will redo it, with some sadness.
Unless the lift is VERY rugged I doubt the forks will handle a 5K lift with the hook anywhere but at the butt of the fork.
As for the connector, Since most forks can be slid for adjustment I would narrow the cross bar down so only the hook attachment separates the forks. I would also put a better hook on there.
Everything about it looks way undersized to me. The tubing is much too light as is the hook and swivel. All lifting items are designed with a safety factor of x5.
On the MSC site, item number 30116016 is a 6000# rated forklift hook plate for $197. Not cheap, but not terrible either and if there is an issue you have a manufacturer with product liability insurance to blame.
Is it completely safe? There is no maybe. Normally everything seems good until suddenly it isn't.
(In most jurisdictions) ALL lifting equipment (including ALL rigging) MUST be CERTIFIED by the manufacturer and/or a Registered Professional Engineer, and must be clearly marked with SWL, most also require manufacturer and date of last certified inspection. Has your forklift EVER had a certified inspection? Most engineers will require a certified weldor to perform all work and may also require post fabrication NDT. The engineering expense alone is usually greater than the cost of a new manufactured and certified attachment which also has product liability coverage. You may still end up in court but at least you will not be alone at the defence table. It is probably worth assuming that the prosecution/plaintiff will have done an Internet search and will be asking you why you continued to use a 'homemade' attachment after receiving contrary warning advice.
Your hook does not appear to be a proper lifting hook and I doubt that it is marked for manufacturer and SWL. It is also lacking a safety gate.
It appears that you are using a very very light chain to secure the attachment to the forks. I suspect that you are using an open hook on the chain. I doubt that the chain is certified or approved for welding. I have often written here about my opinion of both chain and those who insist on lifting with it. On most of the jobs I work on, it is grounds for a quick 'free ride to the gate'.
I would not trust any weld made to 1/8" wall HSS to hold any significant or high consequence loading.
Will it work? Probably. Always ask yourself how it (and you) will look in the accident report, and later in the courtroom.
Back yard small business and hobby tradesman do not have the support or guidance of a safety management team or experienced oversight, this is why so many are injured and killed by the failure of both lifting and jacking/blocking systems.
The most we can ever do is to postpone gravity, it always wins in the end.
It is easy to cheat Death. Death's advantage is that it only has to win once.
$200 + T&S will get him a commercial 6,000# rated forklift lift plate with appropriately certified hardware swivel hook with gate, etc. A small price to pay for the extra safety margin and the manufacturer's certification should a failure occur.
McMaster has a 10,000 lbs rated forklift adaptor. Item 3380T33. I will not buy one, yet, but I will keep looking for one cheaply, and if I need one sooner, I will just buy it. McMaster is two miles away from my place of business. I will relegate my current hook to lifting welders and other light items.
Oooh, two miles? You owe it to yourself if you haven't already done so to go to their location and watch material flow developed to a high art. It's probably easier to order online and have it delivered, but the warehouse operation is fun to watch.
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