Gantry Crane – A60 Crucible Handling Equipment

Discussion in 'Foundry tools and flasks' started by Al2O3, May 3, 2021 at 3:23 PM.

  1. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I’ve had this project in the back of my mind for a long time. I now have a casting that can’t safely be poured by hand so I got my rear in gear and got after it. I like these aluminum Vestil gantry cranes but not for $3.5-$4k price tag. Being light and quickly disassembled for storage is attractive.

    1 Vestil Crane.jpg

    I don’t need much load capability. A couple years ago I had a customer scrap a bunch of 3” x ¼” wall aluminum conduit so I saved some with this project in mind. I set out to make some castings to utilize this round stock for gantry legs. I made a couple MDF templates for the pin router, one diameter with added machine stock and one with clearance for the tube, went to town and made a whole bunch of 2” thick annular sections, and then glued them together into tube stock.

    2 Annular Sections.JPG

    Ever try to cope a couple ~4” OD tubes at 30 degrees? I made this jig that held the foam tube at 30 degrees from vertical. It uses the circular base a guide template for the hotwire and it produced a very nice fitting low angle cope. The overall height of the part was determined by what would fit under the boring head in my mill with the knee fully retracted.

    3 Coped.JPG 4 Coped.JPG 5 Coped Assy.JPG

    The patterns for the caster feet and overhead beam mount were simpler by comparison. Here’s a set of patterns all detailed up.

    6 Set.JPG 6.1 Set.JPG

    For foundry use, I figure I’ll hinge one side on my furnace structure and use the gantry hardware on the other side. Sort of like this.

    7 Hinged Gantry.JPG

    I’m sure at some point in the future I’ll have a need for the full gantry so I made two sets of the patterns/castings.

    8 Two Sets.JPG

    I went ahead and gated one set. Also dipped them.

    8.1 Gated.JPG

    I’ll put a tie rod across the feet for extra support. For my foundry pours, it only needs to lift a couple hundred pounds. As a full gantry, the load limit would most likely be limited by the beam and span but I suspect the legs would have no problem up to a 1000lbs. In the future I’d probably have little need even at half that weight, maybe to pull an engine.

    I resisted but eventually succumb and bought a Harbor Freight electric hoist. It’s the 440lb/880lb version. For $134 I couldn’t justify engineering a hoist. The reviews were so-so. The control and power cable were pitifully short and needed to be replaced. Though I don’t need the lifting capacity, the blocked configuration at 13ft/min seems to be a more appropriate lifting speed as opposed to the 26ft/min with the direct lift.

    9 HF Hoist.JPG

    I built the shank and a pouring cart for my A60 years ago. At the time I thought I’d be sand casting rather than lost foam casting thus the pouring cart. I’ll use the wheels and the shank on the gantry.

    10 Cart Anotated.jpg 11 A60 Open-Closed Sized.jpg

    When I get the crane done, I’m planning a dry run or two pouring sand to get the feel of it.

    Best,
    Kelly
     
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  2. DavidF

    DavidF Administrator Staff Member Banner Member

    Witches ride broomsticks and warlocks ride....
    upload_2021-5-3_19-22-50.png
     
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  3. Petee716

    Petee716 Gold Banner Member

    That’s a nice design concept and pattern strategy on those legs. I assume the reference you made to the boring head height was so you can bore internally to fit the tubes. And you’ll join the feet to the main assembly with internal 3” tubes bolted through the bosses? Assuming that’s how you’ll do it, will you truncate the tube ends to maximize penetration? Just wondering. I’d take all I could get!
    Impressive work all around.

    Pete
     
  4. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    That's pretty much it Petee except for the truncation part. All the tube ends will be square. I only have one diameter of penetration into the blind pockets for the angled legs. Anywhere there was a blind pocket, the casting has a thicker wall with ID of 2 1/2". The rest of the tube is only 5/16" wall. On those leg pockets it seemed like one diameter would be enough if I put a tie rod between the caster feet......otherwise, load would create one heck of a lot of leverage on the leg pocket. With a tie rod on the feet, it is just basically sitting on the tube pocket. That's what the ears on the caster feet are for......a triangulating tie rod that can be tensioned. On the vertical center tube pocket, just 2" of each end have machine stock for a through hole sliding fit over the vertical pillar. The rest of that tube is 3 1/8" ID x 5/16" wall for tube clearance. The conduit is actually 2.9" OD. The vertical tubes in the central casting have through holes for height adjustment and are secured with 1/2" hitch pins through the casting bosses. The rest of the tubes are basically held in compression but have bosses for set screws......at least that's the plan.

    If I didn't limit the size as I did, the part got so massive I wouldn't be able to pour it without the gantry crane I was making it for....LoL!

    Best,
    Kelly
     
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  5. Melterskelter

    Melterskelter Gold Banner Member

    How will you heat treat the parts? T5? I guess gantry crane makes my mind go in the direction of broken castings and I know the castings I make and T5 are not as resistant to fracture as most commercial stressed castings. At the same time, for this particular application, your parts should be plenty strong for the anticipated load. The other possibility is that you may have back door access to more formal HT facilities due to your prior life. ;-)

    Denis
     
  6. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Yes T5. It's certainly valid concern regarding the structural integrity of lost foam aluminum castings. But, the load bearing areas are 1/2" wall.

    Barring gross casting flaws, there is plenty of material there. For a 200lb lift in my foundry use I thinks it's a non-issue. Even with 500lbs a side on the gantry, it's hard to see how there could be much stress with the triangulated design I've described, and most all of the loading is in compression and/or shear, but as I said, it will likely never see more than 250lbs per side in my use. Would I trust a leg assembly to hold me if I climbed up and hung on it........yah no problem.

    Now for big spans, the beam could be a different discussion.

    Best,
    Kelly
     
  7. oldironfarmer

    oldironfarmer Silver Banner Member

    Looks great Kelly!

    I envy your foam processing setup.

    I've always had poor luck getting a gantry to roll where and when I want it. The bigger the wheels the better. I've worked on a jib crane design for large crucible handling but breaking static friction with less rolling friction always causes you to swing and overshoot. For additional control I've been considering a motor driven wheel for swing control.
     
  8. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Thanks OIF. Other than initial positioning, I'm hoping to not have to roll the gantry on its wheels at all during the pour, just position the flask where it can be reached with shank with the hoist rolling on the beam.

    If this was going to be a one-shot deal, I may have just used lumber...........but I have bigger plans for it's use and where's the fun in that?

    Best,
    Kelly
     
  9. oldironfarmer

    oldironfarmer Silver Banner Member

  10. Tobho Mott

    Tobho Mott Gold Banner Member

    Bill T from alloyavenue showed a mod to his gantry crane's wheels that allow it to roll back and forth (presumably) easily on some lengths of pipe.

    Could maybe be helpful to anyone trying to set up for big pours, perhaps...

    See 3:50ish here:


    I'm slowly working up to being able to use my big furnace and use the #70 crucibles, so I'll be watching closely. Just picked this up used, got a great deal on it compared to a similar hoist I looked at on Princess Auto's website:

    20210428_152613_copy_520x1040_1.jpg

    Thinking I should be able to bolt it down somehow and use it to pick up the big crucible and set it down on a plinth into one of the 2-man shanks, perhaps before I have a crane that could be used for pouring with the solo shank.

    Not sure if this helps Kelly too much, but I'm also posting this here as idea fodder for anyone trying to figure out large crucible handling who finds this thread by its title.

    Jeff
     
    Last edited: May 4, 2021 at 9:18 AM
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  11. Petee716

    Petee716 Gold Banner Member

    Leverage on the pocket makes sense. It seems you've made provision for the strength issue. Nicely done.

    Pete
     
  12. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Track is a good idea if you don't have a smooth hard surface. When you get a load on, one small pebble can stop the show.

    Looks like a nice little jib crane. Not sure how long the arm is or what load you're envisioning but as those become appreciable, that will likely require sinking a post in concrete in the ground. Might also keep your eye out for a little hydraulic unit to run the cylinder so you don't have to pump it.

    I think Melterskelter's rig seems to do a very good job and as far as simplicity and reliability, pretty hard to beat a big lever.......move the world!

    Best,
    Kelly
     
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  13. Tobho Mott

    Tobho Mott Gold Banner Member

    Here's a reminder of melterskelter's lever-tongs, since you mentioned it:



    It does seem just about ideal for big solo pours. I had Denis' setup in mind when I decided to go for the jib crane (thanks for the correct name, I'm new to cranes) as the core of a possible liftout strategy. I haven't really thought through all the details yet but because it swivels, I figure maybe I can set it up quite close to the furnace with the arm set as short as I can make it work to be able to set down a bigger crucible than I can handle with solo handheld tongs and shank nearby (not necessarily the huge #70's but maybe). It's good up to 1000# (500 fully extended).

    Eventually one day I'd like to setup something bigger so I can use the 70's (and have a need to pour that much). This might or might not be able to work for the liftout part of that, but I'm pretty sure it could work in the meantime just for enabling bigger pours than I can do now using my bigger furnace(s). My neighbour is already trying to talk me into selling it to him, so I don't think I'll end up stuck with it in any case. :D

    You can get a good look at a really nice setup for my biggest crucibles, furnace and liftout/pouring gear as used in their original home here (first two minutes):



    I dream of a shop with a crane setup like Bill J's. You can see how well he had everything set up after decades in business. Maybe some good ideas there for smaller home shop casting setups (yet still big enough to require mechanical assist) too? Shame we can't go back and see IndiScav's shop built foundry crane build thread on AA anymore...

    Enough derail from me though. The crane part foamies look great, this should be a fun build thread!

    Jeff
     
  14. ESC

    ESC Silver Banner Member

    Patterns look great Kelly.
    I have always been intrigued by the ladles that tilted around the lip axis. For single operator pours it eliminates the rearward movement of the crucible needed to keep the pouring sream centered in the basin, or in your case the Kush head.
    With a trolley like yours the swing of the shank handles during the pour keeps the stream centered, but with the crucible suspended below the gantry, that same movement requires either lateral movement of the hoist, slight rotational movement of the gantry itself, or a combination of the two. I may be overthinking this, but if you have more pours on this scale, eliminating one more variable might be helpful.
     
  15. Melterskelter

    Melterskelter Gold Banner Member

    For and aft movement of the pouring lip might be mitigated by making a rectangular pouring basin with the long axis perpendicular to to pivot axis of the crucible. It does not take all that much. I make life easier on myself by using a large pouring basin—-no cute little keyholes for me! I figure I hit more bullseyes with bigger targets. ;-)

    Denis
     
  16. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    I won't know for sure until I do the trial pours but I was thinking (hoping?) since the shank is tethered to the hoist by cable, that will provide some degree of freedom, (maybe as much as a lateral circle of manipulation a foot in diameter?) along with the fact that it can also teeter and rotate about the lifting axis, so even though it is hoist lifted there may still may be a fair amount of manual manipulation available......fingers crossed..... The flip side is what can move will and must be controlled. With the weight supported it's not that big of a mass to move a little.

    I am planning on using a larger pouring basin, not just for a more generous target, but also a larger pouring buffer for that infamous lost foam pause followed by the guzzle. For this size pour it could be quite the gulp, and those occasional burps back through the cup could become a big belch!

    -Aim small, miss small. :)

    Best,
    Kelly
     
  17. Jason

    Jason Gold

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  18. Billy Elmore

    Billy Elmore Silver

    We used to use hoist in our hand molding department....constantly moving it vertically as you tilt to pour. I was looking at making a hoist until I saw some of the trolleys on here. Now I have a trolley.LOL Much easier to deal with than the hoist if you are pouring from a full crucible and have to raise it while you pour.
     
  19. Jason

    Jason Gold

    Watch Barry pour by himself.
    Barry luke builds channel on youtube. He's got a great method pouring big pots of bronze.
     
  20. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Because it's lost foam and the pattern is oriented vertically, in a flask that is essentially a 30 gallon drum, the pouring height will be 35-40". Didn't seem like a good fit for a pouring cart and I'd still have to extract the crucible from the furnace and get it in the cart at that height. My cart did have power lift but not to that height.



    I can snatch and pour in one operation with the shank from the cart mounted onthe hoist and gantry. Also the A60 will be 50-60% full so that should help. I'm just going to have to experiment a little and see how it works.

    Best,
    Kelly
     

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