Crucible handling

[creast]

I have just bought an A5 Morgan Salamander Super crucible and on inspection I noted that the tapered/curved portion is way less in proportion to the height of smaller crucibles that I use i.e A2 size.
I now have to make new lifting tongs and a pouring shank for this and in the past I aim to hold below the waist on the barrelled section so as to support and not put excessive compression on the crucible.
This crucible puts this point well below the half height which concerns me on a stability during pouring/lifting.
Has anyone experienced this?
Maybe I need to support on the barrelled section with additional hoop supports further up?
I have modelled, as best, the basic shape and a section view is attached.
Rich

 

[GreenTwin]

For some reason, this thread is not showing up in my "Latest Post List".
Not sure why.

The A-shape do have the taper a bit low, and I did have an A10 flip out of my pouring shank, full of iron.

Morgan says support the crucible I think from the bottom 1/3 (check me on that).

I was using a crucible retainer, but crucible sizes vary slightly even in the same size and shape.

I redesigned my pouring shank so that the retainer dropped down from the top, and was adjustable, and so that works no matter how low the crucible settles down in the shank.

For lifting tongs, I have positive stops on mine, and I think to some extent I could perhaps adjust them maybe one crucible size up or down by changing the stops.
One commercial lifting tong I have has fingers that can be adjusted in and out to allow use with a couple of crucible sizes.

I make a plinth on the ground out of firebricks, and set the crucible on that.
The shank sits on top of the bricks, supported by the heat shield.

Having the centerline of the pouring shank so low on the crucible gives a very neutral pour.
Some shanks that grip up high on the crucible add a lot of torque to the shaft, (mass/force times distance) which can make pour control difficult.

.

 

[GreenTwin]

Here are my lifting tongs.
They came out a bit wider that what I woud consider optimal, but they work well.

The lower support needs to be up about an inch from the position I used.

The upper guide shoes are for support, and don't really much if any gripping.

.

 

[creast]

Thanks Pat,
That clarifies my observation and has given me more ideas what to do with my equipment.
Cheers
Rich