Anyone had any experience using borosilicate glass?

So this might be a longshot but I figured I’d post it to see if I get any feedback…

I’m freelancing at the moment with another designer that is bringing a product to market in the coming months (hopefully).

There is one component that he is very eager to have made using borosilicate glass (the same thing Pyrex dishes are made from) but we are having trouble with some of the tolerances. We require a tolerance of +/-0.5mm but everyone comes back with either +/-0.8-1mm

Theres not that many suppliers/manufactures out there and the ones we’ve initially had good communication stating they can hit the +/-0.5mm eventually at the prototyping stage come back with a “actually it’s going to be +/-1mm”

Just curious to know if any housewares folks have any good resources/directories they could point me towards…?

Maybe there is some information here that you may find useful:

They’ve also been very helpful when I’ve contacted them in the past; try to contact them to advise regarding your =/- .5mm tolerance.

I remember hearing in the Core77 podcast with Craighton Berman that he had a good supplier for his product and was going to put it in the show notes (but I dont think that happened). You might want to contact him to see if he can help.

I think you may have to re-think your tolerances.

Pyrex and Bodum must make millions of items a year and their designs always have features to incorporate large (ish) tolerances.

It occurs to me that manufacturers of glass hypodermic syringes might be a possible contact point. Im not familiar with the ISO 594 standard on these devices, but I would assume that the tolerances are a bit tighter than for a coffee maker.

i.e.

or

http://cadenceinc.com/catalog/category/glass-syringes/

Glass syringes start out as tubing.