Setting stones with pre-made settings

How much “slack” is there in the pre-made settings? They mostly
seem to come in whole mm sizes (3 mm, 4 mm, etc) but sometimes
stones I see are “odd” sizes, 3.5mm or 3.15mm.

Some I’d like to get are sized 3.75 mm. This particular dealer
notes plus or minus .3 mm per stone for this particular batch, plus
or minus .2 mm on others.

So if I got 4 mm snap-set premade settings, would I just have to
tighten by hand for some stones? Or do “off” size stones just have
to be set into custom made settings?

Thanks.

Hello H. Deiser When I have stones that are 3.75mm I can (most of the
time) use them in conjunction for a 4.00 mm setting or a 3.50 mm
4-claw head. but most of MY stone dealers stock all stones in CZ’s
and have the 1/4 mm differences… Remember that after the stone
setting the claws should be vertical in all views, not showing being
bent out of proportion ! keep the “heads” polished prior to setting.
okay! here is my answer…“by hand?” no I use a pair of small nosed
pair of pliers. :>) if you do have a problem, here is just what you
should do, use a little pointed broken bur and open up the smaller
claw head and allow a slightly larger stone to be set into it. Don’t
jam in a larger stone and hoping that its gonna work, work with the
little size to 4 claw head ratio e.g. 3.50 CZ to a 3.75 mm head, got
it? if you still can’t find your correct stones, look for another
dealer!..Gerry