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They have these things called trucks. They ship things LTL all over the place for not much money. Pretty cool idea really.
I cannot fathom trying to make something to meet your needs for your nothing budget.
I have seen atleast 25 service truck type cranes for sale in my area for under $2K in the past 10 years and I haven't been looking for one. I have almost bought a couple different trucks for cheap with knuckle booms on them, but I resisted. If I could own and drive a class 8 without spending a ton of money on registration and insurance I would.
If you need it save your money and buy it. You cannot possibly build something that works and is safe for what you can buy a nice used one for.
If you can't afford a few thousand for a crane truck to pick gates and set trusses why are you doing such things?
Live within your means. Use truss jacks and make friends with guys with strong backs maybe.
Doesn't sound like a crane is in the cards for you unless the crane fairy drops one buy for you.
Ahh... The naysayers. If only I had spent a lifetime acquiring things to build things with and out of.
Are cranes really so complicated that they can't be built? Nobody bats an eye at lifting a thousand pounds with a POS harbor freight lift, but I can't put one together ( better no less ) with materials at hand? I'm pretty sure people, not magical crane fairies build cranes. Right? I build things, it's what I do.
You guys ever ask a fisherman why he doesn't just go to the store to buy his fish?
Still looking for knowledge on the building aspect of the base. Not so much a lecture on life.
In the statement: "If only I had spent a lifetime acquiring things to build things with and out of." You completely disregard the required skills to do such things as build a crane. I do not have an engineering degree, but I do design and build things and when the numbers get tough I call in the people with the paper that says they can calculate such things.
The disregard with you for how important safety is with a crane is hard to grasp. If it doesn't work property damage and death can occur.
I think your advice train has run out. You balk at the idea of spending pocket change on a real crane insisting you can build it cheaper. Sure.
"Cheap" and "Crane" don't mix.
I hope nobody is injured or killed because it's too hard for you to use the Craigslist search function.
Your asking for some conflicting information. You will have a very difficult time attempting this project if you want it safe, easy, cheap, and have the required capacity. There is a reason why cranes cost what they do.
Since you have admitted to not knowing how to do crane design calculations, then it is apparent you probably do not understand the forces and their magnitudes that is involved with this project. This is why you are receiving some of the "attitude" from some of the posters.
It is good to ask questions when you do not know how to do something but when you do ask, you also need to listen to what is being said, even when it is not what you want to hear. If you go back and read the replies, you will find that there are some good answers even if they are embedded with "attitude". You need to read up on moments and reactions. Then you will be ready to start to ask questions that are worthy of mathematical answers.
Designing a simple boom system for straight lifting objects can be very straight forward. In your project you are asking for a telescoping boom that pivots from a central base. Properly designing a slew bearing is a difficult and complex project and requires more than just stuff that is lying around. Your are asking to lift lbs at 15 ft. This is small carry deck crane capacity territory.
Your idea for using a truck axle hub bearing system has the a very difficult problem of how to mount the crane to a base. If you have been around, you will have noticed that the slew bearings on cranes and excavators are always major wear points and failure points. This happens for a reason and that is the slew bearing has all of the lifting forces concentrated at this pivot point. Proper metallurgy is a must and using components of unspecific origin and metal composition is not the way to do this safely.
To accomplish this project and have it actually usable and safe when you are done will be a challenge even if you have a significant budget. You have not mentioned, the outrigger system, the winch assembly and how you plan on being able to lock or rotate the boom system.
This project is doable if you are willing to forego some of the design features. A simple gin boom mounted on the front or back of a truck might accomplish what you need with materials on hand. This would not allow you to pivot the boom. You would have to move the vehicle to do that but you could lift there desired load.
Designing things is an art form in making compromises and still ending up with the minimum capabilities to function for the application. In your first post, you have asked for a lot with very limited resources. Go back to the drawing board and get your expectations in line with your available resources. Then you will be able to ask some very specific questions and can get appropriate answers.
Your asking for some conflicting information. You will have a very difficult time attempting this project if you want it safe, easy, cheap, and have the required capacity. There is a reason why cranes cost what they do.
Since you have admitted to not knowing how to do crane design calculations, then it is apparent you probably do not understand the forces and their magnitudes that is involved with this project. This is why you are receiving some of the "attitude" from some of the posters.
It is good to ask questions when you do not know how to do something but when you do ask, you also need to listen to what is being said, even when it is not what you want to hear. If you go back and read the replies, you will find that there are some good answers even if they are embedded with "attitude". You need to read up on moments and reactions. Then you will be ready to start to ask questions that are worthy of mathematical answers.
Designing a simple boom system for straight lifting objects can be very straight forward. In your project you are asking for a telescoping boom that pivots from a central base. Properly designing a slew bearing is a difficult and complex project and requires more than just stuff that is lying around. Your are asking to lift lbs at 15 ft. This is small carry deck crane capacity territory.
Your idea for using a truck axle hub bearing system has the a very difficult problem of how to mount the crane to a base. If you have been around, you will have noticed that the slew bearings on cranes and excavators are always major wear points and failure points. This happens for a reason and that is the slew bearing has all of the lifting forces concentrated at this pivot point. Proper metallurgy is a must and using components of unspecific origin and metal composition is not the way to do this safely.
To accomplish this project and have it actually usable and safe when you are done will be a challenge even if you have a significant budget. You have not mentioned, the outrigger system, the winch assembly and how you plan on being able to lock or rotate the boom system.
This project is doable if you are willing to forego some of the design features. A simple gin boom mounted on the front or back of a truck might accomplish what you need with materials on hand. This would not allow you to pivot the boom. You would have to move the vehicle to do that but you could lift there desired load.
Designing things is an art form in making compromises and still ending up with the minimum capabilities to function for the application. In your first post, you have asked for a lot with very limited resources. Go back to the drawing board and get your expectations in line with your available resources. Then you will be able to ask some very specific questions and can get appropriate answers.
Very well put. One little mistake; he spec'ed 1K lbs at 8' and max swing of 15'.
Tdmidget, I was sincere with the "please excuse my ignorance" I don't know, that's what brought me here. But to say I can't understand leverage because i don't know the name of a specific part is ridiculous. I'm not pretending to be an operator, or pretending I know what the actual amount of load will be at the base of the crane, but I get the principle.
Ziggy2, you have given me the most down to earth answer thus far, thank you!
But is it too far out of reach to build a bigger version of that piece of crap they sell at HF? I'm really only expecting about a 200 pound capacity at full reach. To me this seems extremely doable.. It will be used to load stuff onto my truck more than anything. Not lifting overhead with people all around. I understand that safety is an issue, another reason I signed on to this forum. For advice, not lectures and getting personaly attacked. (I'm not sure how wanting to build rather than buy makes me "lazy" or makes Craigslist "to complicated") To say I have a total disregard for safety is just not true. But I do honestly believe this is something I can build. I have to do a lot of projects by myself, and this is what drives my need for such a device. But my budget is very restricted for these kinds of projects. I'm sorry I can't consider $2- "pocket change" for something that will most likely sit for 300 days or more a year. That is just not a feasible option for me. Cutting up a 2-1/2 ton bob truck axel is.
Maybe I should have provided more info as to what I'm after and need. Measurements aren't set in stone, nor the design, or capacity, it doesn't even exist yet. I came here looking for help, clearly we are not on the same page and I am wasting everyone's time.
The design specifications you have given are pretty straight forward.
1k @ 8ft = lb-ft moment load
200lbs @ 15ft = lb-ft moment load
Therefore the design constraint is lb-ft
(going totally off the top of my head with no diagrams or calculator . . . therefore these numbers should be double checked)
What is the bearing spread on the hub you are planning on using? If we assume that it is on the order of 6 inches - and a best case scenario of equal and opposite loading of the bearings to react to the moment load, you will have lb-ft reacted at a radius of .25ft which means the static bearing load is 16,000 lbs.
Given the dynamic nature of lifting / hoisting you should plan on a minimum of a 3:1 factor of safety and more conservatively I would think in terms of a 5:1 factor of safety - so in order to prevent brinelling of the bearing races / rollers you would need bearings with a dynamic load rating of 48,000 lbs to 80,000 lbs in your hub and a stub shaft with a mounting fixture cable of supporting a 24,000 lb-ft
A typical 2-1/2 ton truck might have a rear axle rating of 18,000 lbs tops . . . and if the bearings were individually rated at 18,000 lbs that would be a reasonable guesstimate to see if this is in the realm of possibility . . . which for your 1k load at 8ft would fail in very short order unless you have perfect sinusoidal acceleration on your hoist and boom up/down hydraulic controls (which is unlikely), perfectly coordinated hoist and squirt functions, and a single wrap hoist with cable guides on the drum (which is unlikely given the budget constraints).
I have built a ton (many tons actually) of home brewed lifting / hoisting items in my lifetime - and moved some heavy loads ('s era Tacoma street car across a field and up onto a lowboy), all manner of disabled heavy equipment, etc. using stone age techniques . . .
If it were me, I'd save my pennies and spend the $ linked above plus a few hundred shipping LTL and have a truck mounted crane that will be safe and far exceed the specs you have outlined above.
I have a tendency to be a bit bullheaded and want to do everything myself. Currently I'm building a new shop 40' x 90' with 16' walls and a 24' peak. I spent a day building a skid steer 16' tall crane attachment for my tractor to set 6 25' tall 800# posts. Had a bunch of free materials on hand and maybe spent $100 in materials and about $ worth of my time. I got it done with a fair amount of effort and with the wife with her thumb on the speed dial for 911 and having to endure her lectures nightly. Thinking about some of the lifts, the forces were enormous on the pivot points and likely dangerous. I did it and was lucky. For the rest of my project I happened opon a Skyjack man lift that goes up 22 feet. It weighs # and works perfectly. I got it from Boeing surplus for $. It's 20 years old with 300 hours on it. Works perfectly and was obviously well maintained. New they are $. It has made the rest of my project much safer and efficient from sheathing walls to lifting walls and beams. What I am saying is sometimes you can stumble opon deals that will cost you less in materials and your time, that are well engineered, and will make the jobs much safer. Sometimes it pays to spend your time earning money doing what you are good at and spend your money earning time to do what you want.