The Stovebolt Site Forums The Shop Area The Tool Chest Built a Gantry crane

I am almost finished with my homemade Gantry crane that I will use to pull the engine, lift cab off frame, etc. I purchased a 1 ton chain host from HF that I will chain to cross beam. Braces on uprights not yet installed, but will be 3/4" EMT similiar to upper braces.

...with the added upright braces that is a pretty nice rig. Thanks for showing us.

Looks good. For safety reasons, I would suggest you bring the work to the crane and not the other way around.

Gantry Crane is finished. Very sturdy. The base is attached to the post with singel 7" lag bolts. I will probably add a plywood gusset to keep the base form being able to pivot around the uprights, not much of problem now, but with use may loosen up and become a problem. First order of business is to pull the engine.

Looks familiar.
Heres mine, no motor pulling, just to get the cab off and back on.
http://rides.webshots.com/photo/2195119120083734483uHWizr

I have since updated the winch to something more appropriate.
Hope to get to use it soon as I really want to set the 860 cab back on.

I wouldn't be comfortable putting wood in shear loads like that, but if it works...I wouldn't put any body parts under anything you pick up. I wold be OK with using wood as uprights, but not the horizontals.

Shear?
I see compression and bending.

With more bracing on the uprights it looks suitable to me. Obviously it still has it's limits before stuff breaks.

I agree as with any lifting device you ought to stay out from under the load...

Grigg

Don't they have cherry pickers on craigslist where you guys live? You can probably pick one up for the price of the wood you used.

When you say cherry picker, I assume you mean an engine lift. At least in my case, an engine lift wouldn't have worked to lift the cab off of my 860, not even close. To clear the cab support in the rear, the very lowest part of the cab needed to be 55" off the ground. Also, I bartered for the 6x6s. Hauled some stuff on my gooseneck trailer for a guy and he filled my tank and gave me the lumber. I would never trust my crane to lift a lot of weight but my cab has an aluminum roof and rear panels. When I set it back on there won't be anything in it. No floor pans, no dash, wires etc so feel pretty confident that what I built is strong enough to lift my cab that couldn't weight more than 300 or 400 pounds tops.
Oh and when the cab is back on, those 6x6's have another job waiting for them.

The wood/steel gantry that I built will easily handle the maximum load of 1500 lbs that I plan to never exceed. I lifted an engine off my engine stand yesterday and the gantry performed flawless with no unwanted flex or movement. Rolling the gantry with the engine load was a breeze and the crane remained very rigid.

Grigg...I immediately picked up on that word "shear" as well that R-Bo used. Another instance of anyone who ever built anything not understanding the basic laws of physics and engineering. The moment arm X the weight of the load = the ft lbs required to lift. Example: a 600 lb engine to be lifted at 4' from ctr = 2400 ft lbs needed to lift. There should always be a 50% safety factor added. And that does not even consider the tipping moment of the base. So in this example the crane needs to be able to withstand 3600 ft lbs at the point of failure.

Since I don't know the materials or dimensions used in the Gantry I can't consider it further except to say that the columns appear adequate but the horizontal connecting piece appears (?) light. Might be steel or painted wood? Looks nice however.

No criticisms here, just please always be sure all of you understand what is involved so you can come back and tell us how it all went because we don't have an obituary column.

Not sure which crane is being discussed above, but the craned I built performed flawlessly in pulling the engine. The main cross beam is 2"x3"x1/8" tube steel and spans 6'-10". The base spans 4'-6".

Incidentally, I have an engineering degree (but not a practicing engineer) and I am struggling to understand where there are moment forces (other than insignificant) in my design. Sure, the braces are there to handle the insignificant moment forces at the otherwise pinned connections. But, the forces are balanced.

Sorry for the misinformation. Apparently the correct term is "bending" rather than shear. I was referring to the weight placed on the horizontal beams of the gantry cranes pictured earlier. It is the weight of the object suspended from the top beam as well as the load it places on the "legs" by the two columns (verticals) when the legs are on casters. Wood is not particularly strong as a beam (when bent), but does much better in compression (as a column). That was my concern.

Some texts I have reviewed seem to indicate that bending may be a special case of shear, but I am not sure and will leave that to the engineers to clarify. I know that a shock bolt that goes through one support and the shock is called in "single shear" and if it goes through two supports on each side of the shock (or end link) it is called in "double shear". I am not sure why the beams in question are not in "double shear". Again, anyone shedding any light on this would be most welcome.

Thank you for the clarifications.

Man am I glad I have a forklift.LOL

+1 on that!

Bill

make that +2!

And for longer reach I added 3 point hitch to it and use the boom pole off the tractor. One day I'd like to find one of the fancy forklift booms....

http://rides.webshots.com/photo/2379212210080251109SxrygZ

Grigg

Aw Man!! Don't get me started on improper use of fork lifts and failure from over loading!!!! C'mon, right tool for the job and all that!!