Announcement

Collapse
No announcement yet.

cranes

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • cranes

    Getting on in years... I would like to add a hoist in my garage. Not looking at tons of capacity but one of the small electric rigs (200-400 lbs). My garage roof is supported by prefab trusses (2x4 construction). What sort of ideas are out there for mounting the hoist? In general, is the more joists I span the better the load distribution? If there is no easy answer, how would I do some relevant calculations? Evidently, I am not an engineer; I can fabricate wood or metal support structures but "what do I build?"

  • #2
    Get an engine hoist.

    The 2 x 4 trusses are really not made to support point loads.

    As I recall, those are usually a Fink or Howe truss. If so, and you really have to, then put a 2 x 10 across several, and locate it right at one of the diagonals/verticals joining the crossbar to the rafter.

    But, really, just get an engine hoist.
    2730

    Keep eye on ball.
    Hashim Khan

    Everything not impossible is compulsory

    Comment


    • #3
      Those 440 pound harbor Fright hoists work very well and at $90 they're an absolute bargain. For our occasional use they'll outlast us.
      *But, they move pretty fast so you have to use the snatch block .
      https://www.harborfreight.com/440-lb...rol-60346.html
      Attached Files

      Comment


      • #4
        Find a used electric over hydraulic Hoyer patient lift. Working load 350-450lbs, so plenty strong enough and smaller in footprint that a Horrible Fright product. Check your local Craigslist.
        Buy American.

        Comment


        • #5
          Originally posted by Dunc View Post
          Getting on in years... I would like to add a hoist in my garage. Not looking at tons of capacity but one of the small electric rigs (200-400 lbs). My garage roof is supported by prefab trusses (2x4 construction). What sort of ideas are out there for mounting the hoist? In general, is the more joists I span the better the load distribution? If there is no easy answer, how would I do some relevant calculations? Evidently, I am not an engineer; I can fabricate wood or metal support structures but "what do I build?"
          Without pertinent information such as what you would like to lift and how high, from the ground or from a bench, if you plan on moving it and where if you are, etc, etc...all answers are going to be just guesses and quite frankly a waste of a lot of folks time.
          Location: Saskatoon, Saskatchewan, Canada

          Comment


          • #6
            Unistrut ( the slotted channel) do catenary roller skates well within the desired load, use several, the heavy duty channeling comes in 20 foot lengths, they have clamps for support, even curved bits ( not cheap but quick) I’ve lifted a very large anvil AND stand and moved it on one, I don’t think I’d try moving a Cincinnati No6 on it though!, ain’t age wonderful!
            mark

            Comment


            • #7
              This dustless door rail works great for light hoists and the load rating is no joke. We have a 900lb door at work hanging off two trucks and it rolls almost too easy.
              https://www.mcmaster.com/door-tracks...ack-for-doors/

              A better hoist for your application would be these hook to hook units-
              https://www.amazon.com/Electric-Cont...3&sr=8-58&th=1

              Yes, the more joists you can connect to the better, I have also seen people skin those trusses with 1/2 plywood 2 feet up, which greatly increases thier strength.
              I just need one more tool,just one!

              Comment


              • #8
                If you dead set on hanging something from the rafters I would suggest sistering them up on each side with 2 x 6's. At least the ones that will be carrying the load.
                The best option would be a portable gantry crane if you have the room.

                JL.........

                Comment


                • #9
                  Originally posted by I make chips View Post
                  Those 440 pound harbor Fright hoists work very well and at $90 they're an absolute bargain. For our occasional use they'll outlast us.
                  *But, they move pretty fast so you have to use the snatch block .
                  https://www.harborfreight.com/440-lb...rol-60346.html
                  What company in their right mind would design something like that with no variable control ?? Did the idiots that designed it ever try using it ???

                  I worked at a shop that had one of those, it wasn't a cheap HF one but it was hit the button and cringe. I remember watching the maintenance guys lifting big injection molds from a cart and trying to gently set them down on a steel bench. The guys would rapidly peck away at the button trying to gently lift it and set it down. didn't work well.
                  After lifting the probably 500 Lb. mold and moving it to the table they would rapidly bump the down button to try and gently set the mold down. One inch above the table and the next bump of the button the thing would drop shaking the floor.

                  If you could adapt a variable speed control to the motor it would be OK but being an AC motor it's full throttle or nothing.
                  I have seen these that do have that feature.

                  JL...................

                  Comment


                  • #10
                    I’m no engineer but 200-400lbs isn’t really that much weight. I would suspect a lot of members here are in that range.

                    What are the shop dimensions and how long of a run do you want for the hoist? I wouldn’t be afraid to put one attached to the ceiling but depending exactly what is going on you may need some additional supports.

                    Comment


                    • #11
                      Snow load ratings are 40-50 psf, across the entire truss that might end up being a 2' width x 24' long per truss, total of maybe 2000-2400 lb for the entire truss, loaded evenly. Loading the bottom cross-member at a point is not the same thing.

                      Remember, a truss is designed to take all loads as tension or compression loads. The bending loads are nonexistent except on the rafter, and those are distributed, not point loads. Hanging a lift from the bottom stringer is entirely different, and is not planned for in the design.

                      If you do it, putting the lift near a diagonal/vertical truss member will make the load distribute on the truss as "normally" as possible. Distributing across several will help also.

                      The snow has no transient load such as when you lower the load and stop suddenly, or start lifting it, and also does not swing or provide any side-load. A lift can. Transient loads are larger than the static weight, and need to be accounted for.

                      The trusses are put together with cheap nail-plates, having half inch long "stabbers" punched out of the plate which are all that penetrate the wood and act as "nails". They are fine for normal loads, but a swinging load may "work" the plates outward, taking apart the joint. Those plates are not intended for any sort of side load at all.

                      Is it a guarantee of failure? Nope.

                      But I would not do it unless I had to.
                      Last edited by J Tiers; 11-16-2021, 09:09 PM.
                      2730

                      Keep eye on ball.
                      Hashim Khan

                      Everything not impossible is compulsory

                      Comment


                      • #12
                        Originally posted by J Tiers
                        Snow load ratings are 40-50 psf, across the entire truss that might end up being a 2' width x 24' long per truss, total of maybe 2000-2400 lb for the entire truss, loaded evenly. Loading the bottom cross-member at a point is not the same thing.

                        Remember, a truss is designed to take all loads as tension or compression loads. The bending loads are nonexistent except on the rafter, and those are distributed, not point loads. Hanging a lift from the bottom stringer is entirely different, and is not planned for in the design.

                        If you do it, putting the lift near a diagonal/vertical truss member will make the load distribute on the truss as "normally" as possible. Distributing across several will help also.

                        The snow has no transient load such as when you lower the load and stop suddenly, or start lifting it, and also does not swing or provide any side-load. A lift can. Transient loads are larger than the static weight, and need to be accounted for.

                        The trusses are put together with cheap nail-plates, having half inch long "stabbers" punched out of the plate which are all that penetrate the wood and act as "nails". They are fine for normal loads, but a swinging load may "work" the plates outward, taking apart the joint. Those plates are not intended for any sort of side load at all.

                        Is it a guarantee of failure? Nope.

                        But I would not do it unless I had to.
                        How did you end up with a duplicate post ??

                        JL.............

                        Comment


                        • #13
                          The OP didn't state if he needs mobility or not, the budget he has, or how much headroom he has.

                          There are a few options available at good 'ol Harbor Freight. The pickup cranes can be adapted to many applications for cheap. The rolling gantry is probably over kill for him, but an option if if he'll ever have the capacity needs, and has the headroom.

                          Do a search on Youtube for "DIY cranes and gantries", or even on the pages of this forum. You'll find hundreds of ideas.

                          Comment


                          • #14
                            Loads would be less than 400 lbs (likely 150 -200 lbs) but I intended to use the doubled cable to slow it down. I like the idea (vs an engine crane) since it takes little floor space and is mostly "up there." Otoh, given the relative fragility of the joists to point loads, I am more interested in not having the whole thing around my ears. On second thought... an engine crane looks like a great idea! Thanks all for educating me!
                            Last edited by Dunc; 11-16-2021, 06:36 PM. Reason: spell checking

                            Comment


                            • #15
                              The engine hoist is the obvious solution but presupposes that you have the floor space to maneuver the thing. Same deal with the medical style lifts though they do require less. My shop is not tiny (not huge either) but it does have a lot of stuff in it. There is no way I could move anything around with either of those style lifts.

                              Comment

                              Working...
                              X