# Building a Gantry Crane



## Glenn Brooks (Jul 17, 2017)

iam planning on building a 2 ton gantry crane for my RR shop, similar to the one in the photos below.  It won't be real tall, maybe 8'-9' to the top of the beam.

My big question is how long should the cross beams be, at the bottom, where the casters mount??  Is there an optimum formula for the length of the cross beams - for stability?? If no rule of thumb, what length of footing do you recommend?  

I wish I had taken some measurements when I visited this roundhouse, but didn't think about it at the time, Of course..!






Thanks 
Glenn


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## rrjohnso2000 (Jul 17, 2017)

You can just grab the ratio of height to width of the base from your pics. Of course it's a guestamation but should be good enough


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## GoceKU (Jul 17, 2017)

Gantry crane is a back saver, i've made 3 till now and for the cross beams at the bottom, where the casters mount i've used from 80 to 120 centimeters depending on the hight, and how top heavy it is, the secret to a good gantry crane is its wheels, bigger they are easier to roll on uneven floor, forget about plastic wheels they break no matter the weight rating, i've made my own steel wheels on the lathe, simply cut, face, drill and you done, 100-140 mm diameter.


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## Uglydog (Jul 17, 2017)

An I or H is the traditional build.
I didn't have a trolley for my first gantry build. However, I had multiple rugidized solid rubber wheels. They came out of industry somewhere. 
I chose to use thick wall box tube for the construction, grade 8 bolts as wheel axles, a large extra shackle from which to hang the chain fall, and hot rolled plates for the sides.

Daryl
MN


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## tq60 (Jul 17, 2017)

Something not often seen but could be helpful is a cable system linked to a crank on the side that controls where the hoist trolly is.

Turn crank and trolly moves

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## 4GSR (Jul 17, 2017)

Glen, that is one heck of a diesel electric train engine you have there.  What is it, quarter scale of the real size one?

Back at the old family homestead, we had a gantry crane dad built that had two uprights made of 3" square tubing with .250" wall.  Base was also the same square tubing.  On top was a piece of  8"H beam, don't remember the weight of the beam.  He found some steel rollers about 8-10" in diameter welded to the bottom of the 3" square tubing.  We had a 2 ton chain fall we used on it.  I will say, we picked up two 3200 lb milling machines with it over the years and not once have any issues with it.  I wished I kept it too!


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## benmychree (Jul 17, 2017)

I built one using a design that one of my friends who is a mechanical engineer did while working for a shop that did fabrication.  It used 5" channel leg down with plates welded on the downward side  to mount the casters, it did not use support columns directly under the upper beam that the trolley runs on, but 2" pipe forming an "A" shape from the end and welded onto a plate on the top that was in turn bolted to the "I" beam and were welded onto the 5" channel at the bottom. for lateral stability, a small channel was bolted onto and crossways to the "I" beam  about 24" inward from each end; to these, another pair of 2" pipes were welded to the small channel and to the larger bottom channel, just inboard of the first two pipes mentioned; An advantage to this construction is that it leaves the side open for access, and also the whole thing can be disassembled to be moved, if necessary.  We used casters about 4 or 5" diameter with cast iron wheels.  I have a D size blueprint of it, and could get it reproduced and sent at nominal cost if anyone is interested in the details.


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## woodchucker (Jul 17, 2017)

4gsr said:


> Glen, that is one heck of a diesel electric train engine you have there.  What is it, quarter scale of the real size one?
> 
> Back at the old family homestead, we had a gantry crane dad built that had two uprights made of 3" square tubing with .250" wall.  Base was also the same square tubing.  On top was a piece of  8"H beam, don't remember the weight of the beam.  He found some steel rollers about 8-10" in diameter welded to the bottom of the 3" square tubing.  We had a 2 ton chain fall we used on it.  I will say, we picked up two 3200 lb milling machines with it over the years and not once have any issues with it.  I wished I kept it too!



I don't think that's Glen's engine. I have seen in pics his steamers.  I think that's just where he took some measurements, but yea, it's impressive.

Glen scale the upright, if it's a 6" upright, figure out the scale, then measure the base, and apply the scale to figure out it's real length.. it should be close.


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## Silverbullet (Jul 17, 2017)

The most usefull indoor gantry crane I've ever seen is the one Keith Fenner built for his crowded shop. He's able to steer it all around and over his machines. The uprights swivel at the top . Get the trolley with the roller option not much more to by but so much easier then yanking the thing around. Some of his YouTube's he shows his crane.


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## 4GSR (Jul 17, 2017)

woochucker said:


> I don't think that's Glen's engine. I have seen in pics his steamers.  I think that's just where he took some measurements, but yea, it's impressive....................................


Yeah, I realized that after I posted.  Still impressive!  Thanks.


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## Tom Howland (Jul 17, 2017)

Glen, I would say a 1 to 3 ratio. 3 on the tall leg.  1 on 1/2 of the total bottom leg.


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## whitmore (Jul 17, 2017)

Glenn Brooks said:


> iam planning on building a 2 ton gantry crane for my RR shop, similar to the one in the photos below.  It won't be real tall, maybe 8'-9' to the top of the beam.
> 
> My big question is how long should the cross beams be, at the bottom, where the casters mount?



There's recommendations for straight ladders, that the rise:run should be 4:1 .  
That would suggest a 4 foot base (two ft from center) for an 8' hoist, but shorter would work
too (because you have nonrotating joints, which the ladder doesn't).   It would be useful, too, to know
exactly which doors the crane has to potentially navigate, and which pickup or flatbed trucks,
might have a heavy item in the bed, before defining the full sizes of the project.    
With the right design, a short-topbeam gantry can slide one leg under the truck bed, so needn't
straddle the full width.

I can tell you from experience that a bookcase taller than 75" and/or wider than 24" will sometimes
have problems getting through a door, or up a stair, or down one.   Also, pallets and lifting points are your
friends.


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## Glenn Brooks (Jul 17, 2017)

Just came back from picking up a couple of lengths of 6" x 6"x 5/16" A 992 structural  I beam. More like H beam.  No doubt waaay oversize for what I really need.  However, with Craigslist you work with with you can get I guess.

Yep, the loco in the picture is an 18" gauge, 1/3rd scale  true diesel at the non- profit Swanton Pacific Railroad, north of Santa Cruz, Ca.  Way bigger than my small 12" ga stuff.  The S&P RR is the permanent home now for the ex- Overfair steam locomotives that operated as people movers during the SF Exposition in 1914.  Visited last spring to take some pics of the diesel for another train guy in Texas who wants to build in that scale.  The Swanton Pacific is operated by a group of volunteers, funded by a perpetual trust set up by Al Smith of Orchard Supply fame back in the 70's.  They have a mile of track and some nice shops on Mr. smiths old ranch, donated and operated by the University of California regents.  The land trust says if the Regents don't maintain and operate the RR in good repair,  they loose the 3000 acre ranch!  Al was a Smart guy!!   Here's a photo of two of their steam loco's.  The bottom one just had a new boiler made up and installed.  Stills needs the outer shell put back on. Lots of fun and very impressive if you like hobby railroading.  Also, one reason their gantry and backshop equipment is so massive.







So regarding the gantry, It looks like the height to length of base ratio for these things is generally in the range of 2:1 to 4:1 depending on manufacture.  So in line with what several have advised above. With the weight of these beams I just bought, Iam now also thinking weight aloft could easily affect this  base measurement.  These babies are heavy.   I don't want to deal with an unnecessarily top heavy assembly.  Anyway, it's off to the shop now to take some more measurements of equipment, then decide if I want to keep these monster beams or look for something smaller. I think I really need to stop jumping on these killer deals on Craigslist.

Thanks much for your suggestions and advice. Very helpful!

Glenn


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## woodchucker (Jul 17, 2017)

Glen, if you have the room, the heavier beam just gives you some extra comfort knowing it won't be the cause of a buckle.  So maybe you need to go a little wider  on the supports to control the top heavieness, but better to have too much than not enough on a gantry.. Just my opinion.


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## rock_breaker (Jul 18, 2017)

Hopefully some steel design/fabricators will offer some advise here . Could not find the same measurements of your beams but did find a six inch high by 4 inch wide beam in my 6th edition Steel  handbook and the uniform load published for that size on a 10 foot span is: Beam size 15#/foot =16.2 Kips; Beam size 12#/foot =11.6 Kips and Beam size 8.5#/foot = 7.4 kips with a Kip being 1000 pounds. If memory serves me right a point load should be 1/2 the uniform load. No doubt you are aware that a deeper web will yield greater strength for example a 10 X 4 beam with the following data: Beam size 15#/foot will hold 22.1 kips or 11000 pounds for concentrated load. Loss of 4 inches in height but gained 3000 pounds lifting capacity.  
Lots of good advise given here, +1 on larger wheels.
Have a good day
Ray


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## 4GSR (Jul 18, 2017)

A wide flange beam like this, 6 x 6 x 5/16, is not designed to for a trolley as used with a hoist.  The angle of the wheels will not match up.  Not to say you couldn't make a new set of rollers to match the flange angle which is probably less than one degree.  As for loading, this will take a bit of calculating to get the results needed.  Here's a link to one set of calculations that can be used.  It's been a while since I've used any of these calcs since my line of work now doesn't involve beams.

http://www.engineeringtoolbox.com/beams-support-forces-d_1311.html

Also, the normal safety factor to use here is at least 4 or greater.  This is based on material yield .5% offset, not ultimate yield.

Ken

Edit: There are a few things that can be done to a beam to strengthen it up a little if needed.  Rather than do this, I would suggest getting a proper size beam instead.


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## Glenn Brooks (Jul 18, 2017)

Ray and Ken, thanks for the follow up and suggestions.  The 6x6 beams (there are two pieces) are grade A992, rated at 65 kpi- so 65,000 lbs.  it's often used in girders for bridge construction. Probably not mentioned in your book as it's a recent high strength material release meant to replace older structural steel compositions.

 Ken, I've been looking into trolleys.  A couple of 2 ton trolley manufacturers say their units will accommodate either flat flange or tapered.  However, I plan on exploring farther to verify.  Thanks for the heads up. Worst case these could be used as footers to add counterbalancing weight at the casters.

Last night, measured the equipment footprints for the four or five things I likely will need to lift. Now leaning toward a beam span of 7' or 8' rather than the more narrow 3' I first proposed.  6 1/2' clears the bed of my pickup. Also 6' clears the width of my old Farmal Cub tractor.  I need to split the case on the old cub at some point and replace the rear main seal. So supporting both ends of the cub with two lifting points, positioned end to end would be a good solution. 

However, a 3' to 4' beam span is ideal for all the rest of the equipment. The 4' extra feet width will sure make a difference storing this thing in my shop. The uprights for an 8' wide gantry soaks up a lot of high value space right around the edge of my work tables. Still debating. I need to get a sign that says "More thinking needed!"

Glenn


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## 4GSR (Jul 18, 2017)

Glenn,

That's good that the beam has a rating of 65K psi, that's literally double that of A36 steel beams most of us use.  What do you think would be maximum load you will be picking up with  your gantry?  
I'm not a license engineer, but I'll be glad to run some numbers for you if you like, if you don't want to mess with it yourself.  

I didn't think about it, I believe there are a couple of guys that hang out here that are more qualified to run number than I am.  Maybe they will chime in and offer help.

Ken


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## Glenn Brooks (Jul 19, 2017)

Thanks Ken,  my max load shouldn't exceed 1800#.  That is the weight of my Utilathe.  Heaviest piece of equipment I own at present.  I have on hand an existing  2 ton chain hoist, which I plan on mounting to the beam, once the frame is fabed up. So Iam shooting for 2 ton capacity overall. However doubt I will ever need to lift more than a ton. 

I appreciate your offer to do some calcs on this.  What kinds of results would show up from running some numbers, and what inputs  should I provide?

Glenn


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## 682bear (Jul 19, 2017)

I built this one a couple of years ago... the beam is 6x6x5/16 h beam supported on an A frame made of 2 inch box, 1/4 inch wall... I currently have a 2 trolleys on it, 1 with a 1 ton hoist and 1 with a 2 ton hoist.

It is 10 feet wide and 9 foot 10 inches tall, so it will barely squeeze under my 10 foot roll up doors on my shop.

I built it mainly for removing engines and such, so I figured it would never hsve to lift over 800 lbs or so... but then I bought a lathe...

I'm guessing the lathe weighed around 2000 lbs... the crane lifted it easily.

I need some heavier duty wheels to put on it... my current wheels are only rated at about 750 lbs for the set. I didn't even think about that until I had the lathe set down on the roller dollies... that could have been a bad mistake, but they handled the weight.

-Bear


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## f350ca (Jul 19, 2017)

Ken I was using the formulas on the link you posted for years, but now you have to pay a membership. Guess everyone has to make a living.
Glenn, for your trolley beam the design is usually based on deflection. If the beam bends too much you wouldn't be able to push the trolley up hill as you went to the side. Same as with a boring bar the strength of the material has no effect on that. Totally dependant on material (young modulus of elasticity) , cross section (specifically moment of inertia) and span.
Ran the numbers, for your 1800 pound load in the middle of an 8 foot beam you would get 0.011 inches deflection, not including the beam weight. Might get that much more from the weight of the beam. The calculations were from a new sight I found, was too lazy and its too early to check the numbers by had but that sounds about right for that size beam.

Greg


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## 4GSR (Jul 19, 2017)

Greg,

On deflection, that's about right.  And yes, you can't get around it, any material will deflect a certain amount based on Young's modulus.  My question to you is, what was the stress level at this level of deflection?


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## f350ca (Jul 19, 2017)

You have to pay to get the calculator I found to give stress Ken. Wish the one you linked to was still free. With that deflection on an 8 inch beam you'd be no where close to the elastic limit.

Greg


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## Glenn Brooks (Jul 19, 2017)

Greg,  Thanks much for doing that. Very good to know.  Sounds like reasonable deflection for what I will be doing. 

Bear, nice looking design.  Can you advise the width between centers of your casters?  This is the one dimension that seems the most variable with people I have talked to.

Glenn


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## f350ca (Jul 19, 2017)

No problem Glen, That deflection over 4 feet from centre would be unnoticeable when you tried to move the trolley.

Greg


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## 4GSR (Jul 19, 2017)

The gantry crane dad had, legs were 4 foot apart, up rights about 8 foot, or put this way, the overall height was right at 10 foot.


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## 682bear (Jul 19, 2017)

My casters are 5 feet 9 inches apart... it is very stable at this width. I would think you could make it a good bit narrower and not have to worry about it being tippy.


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## brino (Jul 19, 2017)

Glenn Brooks said:


> my max load shouldn't exceed 1800#. That is the weight of my Utilathe. Heaviest piece of equipment I own at present.



That might change quickly with the new ability to move heavier equipment! 
-brino


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## expressline99 (Jul 24, 2017)

I'm drooling over here.  You guys make me think too much about what I "could" do.


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