Gantry Crane – A60 Crucible Handling Equipment

I completed fabricating the hoist carriage. Here’s all the bits and pieces. Some lathe work for the axles and cut up some square tube for the legs.



……..and assembled.



….and mocked up on a beam with the pieces that mate with the Gantry post castings and furnace cart.



I have a little finagling to do with the pouring shank and then it’s time to fit it up and give it a test drive.

Best,
Kelly

 

The shank is ready for action.



Time to assemble everything and do some test runs. Have company all holiday weekend so will be a few days.

Best,
Kelly

 

What weights more, the pouring shank or the table saw??

 

Ohh, a wise guy......Hey Moe!

Best,
Kelly

 

I milled flats on the legs/posts everywhere the set screws bind the tubes, polished the sockets a bit with a cartridge roll, and applied a little paste wax. It’s a lot less grabby now and think I'll be fine with respect to galling but will need to be careful not to ding the tubes when disassembled.



I assembled everything and played with it a bit. The hoist has a lifting speed of 26 ft/min or 13 ft/min with it doubled with the lifting block. It’s supposed to have 400/800 lb lifting capability respectively. I think either would work but I like the slower speed for better control for actively adjusting pouring height.

Here’s a few pics. I haven’t drilled the hole in the vertical post yet because I was having trouble measuring perpendicularity to the milled flats so I just marked and clamped it and will disassemble the walking end to drill the height adjustment holes. There was ample beam travel to snatch the crucible and position the flask to make the pour without needing to move the Gantry tripod. The cords need to be lengthened and routed better,



My larger furnace was intended to be fuel fired for melting but has an 8kw resistive electric insert for heat treating. It’ll take a while to melt 40 lbs of aluminum but think I’ll give the resistive heating a shot. I have a bucket of sold sprues, gates, and scraps. I think I’ll do a test run to see how it all goes.

Best,
Kelly

 

All good points. At the moment, it will take just about every pound of sand I have, which is about 450lbs and why that flask is on wheels and can tilt to dump.......but I only have one flask that size. Sand is cheap but setting up the larger furnace and gantry is a non-trivial one-man job, especially compared to just rolling out my smaller furnace (full A20 capacity) and flipping a switch. So if the required shot size was <20lbs of aluminum, I'd do multiple melts with the smaller furnace poured by hand rather than setting up the bigger rig.

Best,
Kelly

 

I did a test run of the Gantry and A60 today. Glad I did. Lots of little glitches and areas for improvement. I charged the crucible with all the small sprue stock and scraps that had collected in my scrap bucket…..



Then topped it off with some larger scrap…..



Parked it in the cold furnace and flipped the switch. First surprise was the slower than expected rate of temperature climb in the furnace. With the furnace mass, crucible and charge, I figured it would probably take a couple hours. After almost two hours, the Thermocouple was only registering 450C but I peaked in through the vent and saw a completely melted charge. With the heat only applied at the bottom, along with a large crucible charged with 30lbs of Aluminum filling up the majority of the furnace bore, the center of the furnace lid where the thermocouple lives was not nearly as hot. I’ll have to give some thought to that but it may be no big deal……..just need to watch and measure the melt temp.

Then I went to lift the furnace. The lift used one of those imported wireless controls, which failed. Luckily I had several provisional options and used a jumper to power the linear actuator and opened the furnace. I’ll fix this before the next go round.

Then opened the shank jaws, positioned it about and grabbed the crucible, only to discover plinth had stuck to the crucible, which ordinarily wouldn’t be too big of a deal except with the added resistive electric section, the furnace doesn’t open high enough to clear the crucible with the added plinth, so then I’m rapping the plinth on the furnace base with a half full A60 stuck to it…….and fortunately it let loose. Next time, it will get a couple pieces of cardboard. So I proceeded with the pour.



I had just zip tied the cheesy hoist control tether to the shank. It was awkward to actuate the hoist switch with my back hand and at the same time steady shank which was fairly nose heavy. I’m going to add a little counterweight to the tail end of the shank for better balance and make a purpose-built switch/trigger so I can keep both hands on the shank and comfortably control the hoist switch. I did extend the power and control cords. They were ok but I think I will add some further cord management and routing hardware.

I had positioned my largest ingot tray on top my flask to simulate the pour height for my intake manifold. Each of those ingots is about 8lbs so poured 24 lbs at that height. The good news is that was easy even with the aforementioned, as was lowering the crucible to ground level pouring of the other ingots and parking the crucible on a couple bricks.



I let the furnace run empty up to 1000C and shut it down. Not sure if I’ll preheat the furnace before introducing the crucible next time. I think I could have executed the pour but I’d just assume not have to contend with such things so I’ll be making some refinements.

Best,
Kelly

 

I’ve got the Gantry completed, some refinements to the shank, furnace controls, and other pouring aids.

I added a more rugged and easily accessed switch for the hoist on the shank.



I also added a tail to the shank to accept ballast to better balance the shank.



I made a flask extender by sheering and slip rolling some sheet metal. When this is installed in my large molding rig, it makes increases the interior mold height to 40”. Since it’s on a frame with casters that makes the pouring height almost four feet! The intake manifold is as tall as my big flask with the extension and I figured I was going to need some additional sprue and head pressure, thus the additional extension.



I drilled a single hole in the Gantry post to suit use with the foundry furnace. Completion of the other side of the Gantry will happen another day. I made a more robust reversing circuit with limit switches for my larger furnace.

I made a large reusable offset pouring basin. With the extension, the opening is 6x6 and holds almost 10 lbs of aluminum brim full.

http://forums.thehomefoundry.org/in...le-offset-pouring-basin.688/page-3#post-39356

It will hopefully provide a large buffer volume of molten metal and if I can’t hit that target I need to hang it up.

I had to make a new IFB insert to hang my contact pyrometer in the furnace lid. It didn’t have enough length to reach the molten metal in the larger furnace. Cut some sacrificial cardboard to ensure the crucible doesn’t stick to the plinth this time. I’ll use Sr and TiB. And the candles? Offerings for a successful pour.



I needed a place to hang the skimmer and pyrometer so made a mount. I don’t have the additional Thermocouple display on this controller so I just mounted the hand held to monitor melt temp



Cut up a 40 lb charge from ingot.



Think I’m ready for a 40 lb pour. Need a good weather day.

Best,
Kelly