What is the Minimum Size Prongs That Can Be Wax Cast

[Preston]

I am designing some settings that for rings I design with CAD. I don't use jewelry design software but other 3D programs which I prefer.
I am specifically wondering about what are the size limitations of prongs that a production company can pull waxes of and not break the wax prongs and then the metal (silver) will flow into the prong. The types of settings I am working on now for example are for 4X4 mm squares and 8X6 octagon. The stones are going to be set in close to the ring (I do have the required depth for the stones in the designs) not up high in prongs like an engagement style.

I would like to use prongs about 1mm to .75 mm in diameter may be 2-3 mm long; is that possible and practical in lost wax?

I was also wondering if I could have the seat formed in the prong in the 3d model, this would mean that the area of the prong above the
seat would be smaller still. Is this done on a prong of this size in a wax casting? or are seats in this size prong always cut during stone setting.

Thanks

 

[denverappraiser]

Pulling a wax and casting a 3/4mm prong in silver will be no problem. The issue is going to have more to do with the durability of the piece. Silver is a soft material, .7mm is tiny, and 8x6 is a fairly big stone. Frankly, I would recommend prongs that are considerably bigger. Double?

People preseat prongs all the time and it keeps the price down but it's definitely not best practice. The problem here is that the girdles and pavilions are not al the same, even on calibrated goods. If you're going to stick with the teeny prongs, we're now talking about 0.35mm thick and 0.7mm wide at the tip. That's awfully small. It'll cast just fine but you'll have a tough time milling it and your mold cutter may have issues (I assume you're making a mold).

 

[Preston]

Thank you Denver Appraiser for you reply,

Yes I think trying to pre seat will be tricky and it would be better to cut to fit the seats to the stone in the prongs.

As far as the size of prongs in silver (most likly will use argentium) to adequately hold an 8X6 octagon, I looked at a basket
setting for this size stone from Stuller it was for an earing but I think they sell the exact same one with out the post as a plain
component, and the prongs were 1X1mm with the outer surface rounded, so a U shaped prong profile.

I guess a ring could take a hit in the prong more easily. So you think 1x1mm is a no go, I am not set on this size but am just
wondering from a technical point of view.

A 2x2mm prong seems a little large though aesthetically ? May be 1.25 mm or 1.25 x 1.5 with the loger lenght
extending under the stone for a wider seat area?

Thanks

 

[denverappraiser]

I haven't seen your design, and I"m not the designer in any case. That's your job. 6x8 is a decently large stone, silver is a low durability metal, and 0.75mm cast (finished will be less than that) is a decidedly thin prong, especially if we're talking about a ring here. Your question is if it could be cast. Yes, it probably can. SHOULD it is a whole different train of thought. Normally I don't participate in that sort of conversation but there are plenty of folks here who will.