Sizing of cast rings?

[Dennis]

You result will be the clincher, Josef.

[Icarleug]

Wow, I would not expect anyone to cast rings just for testing, thanks a lot!
Will be exciting to see the results!

/Andreas

[Patstone]

Just to add more to the confusion, when measuring - for instance - hot hands, or "time of the month" can make a difference of a size or two.

[josef1]

Raw castings trees



the wax model, 18 ct white gold, and platinum rings cut from the tree



The wax for comparison size N



Platinum raw casting M (ish)

White gold M(ish) bit of a wobbly cast that one !

[josef1]

Both rings with the inside cleaned up ready for hallmarking



Platinum M 1/2




White gold M 1/2

Hope this helps

[Dennis]

So Josef, the rings became about one size smaller after casting, but removal of metal when polishing the inside caused them to end up a half size smaller.

This is what you predicted at the outset, when you said the wax should be a half size bigger than needed. However the The models made with a 3D printer are rougher than wax and need more finishing. So it is possible that rings cast from wax might need to start three quarters of a size bigger.

Also heavier rings will shrink more, so will need a further estimated allowance.

Thank you for clarifying the problem for us. I hope I have summarised it correctly. Dennis.

[Tabby66]

That Josef is a really useful demonstration of the debate, thank you for taking the time to do it, document it and share!!

Very much appreciated

[josef1]

Hi Dennis that sounds about right,but I still would only go half a size on average size grown rings as depending on which direction the rings are grown on the machine the grow lines effect it differently,I dont have a formula for this it just seems to work out ok. But if you need to make the ring to a certain dimension say for example a 3mm band its better to have a bit of meat on it to finish to the correct thickness so I would add a bit to the outer dimensions

[josef1]

No problem Tabby glad to help. I just hope the ring fits Icarleug If Im in doubt I always go bigger at least she can put it on then get it resized as opposed to not putting it on and getting it resized !

[enigma]

Really interesting thanks for sharing!