Borofloat 33 Glass With Countersunk Holes – Borofloat 33 (CTE 3.25 x 10^-6 /K, 350 nm – 2.0 um); 82 or 90 degree countersinks on holes from 2 mm. No minimum order; DFM review included with every RFQ.
We build borofloat 33 glass with countersunk holes to print – 82 or 90 degree countersinks on holes from 2 mm – primarily in Borofloat 33. Typical use: flush fastener mounting in guards and fixtures.
Specifications at a glance
| Material | Borofloat 33 (SCHOTT float production, wafer grade) |
|---|---|
| Thermal expansion (CTE) | 3.25 x 10^-6 /K |
| Service temperature | 450 C continuous |
| Transmission range | 350 nm – 2.0 um |
| Density | 2.23 g/cm3 |
| Knoop hardness | 480 kg/mm2 |
| Refractive index | 1.471 @ 587 nm |
| Stock thickness | 0.70 – 25.4 mm |
| Maximum blank size | 500 x 500 mm |
| Geometry | Glass With Countersunk Holes |
| Size envelope | 82 or 90 degree countersinks on holes from 2 mm |
| Key tolerance | depth +/-0.05 mm |
| RFQ inputs | PDF/DXF/STEP drawing, quantity brackets, surface and edge spec |
Manufacturing capability
One material, many routes: on Borofloat 33 we also quote double-side polishing, drilling, cnc machining, edge grinding, and multi-step drawings are the norm rather than the exception.
Production route: drilling, cnc machining – selected per geometry and volume. Edge condition: optional chamfered hole entry.
Specification advice
The shop-floor rules that matter here:
- Material note: float tin side must be tracked when parts see coating or bonding steps.
- Hold the controlling dimension (depth +/-0.05 mm) and let secondary dimensions carry standard tolerance – it is the single biggest cost lever.
- Over-specification is the quiet budget killer: a 20/10 scratch-dig face costs roughly three times an 80/50 face, so grade each surface individually.
For the complete framework, see the tolerance design guide and the holes and edges design guide.
Where these parts end up
The recurring buyers of borofloat 33 glass with countersunk holes: mems devices (cap wafers, TGV substrates, motion-sensor lids); microfluidic devices (chips, manifolds, via plates, bonded stacks); led packaging (groove covers, phosphor carriers, package windows). Background reading on the underlying material science: SCHOTT BOROFLOAT product page.
Dimensions still moving? Configure this part live in the 3D + 2D builder below, or open the full custom glass machining 3D + 2D builder to start from a blank canvas.
For adjacent specifications, see 4 inch Borofloat wafers, surface quality guide, Borofloat 33 selection guide.
Common questions
How does Borofloat 33 behave under heat?
CTE is 3.25 x 10^-6 /K and continuous service reaches 450 C continuous, which is what drives its use where float-glass flatness off the line matters.
What sizes are available for glass with countersunk holes?
82 or 90 degree countersinks on holes from 2 mm, held to depth +/-0.05 mm.
Is there a minimum order for borofloat 33 glass with countersunk holes?
No. Single prototypes are accepted, and pricing steps down at 10, 100 and 1,000 pieces.
How fast can prototypes ship?
Machined prototypes ship in 5 – 10 working days. Coated or bonded parts add 1 – 2 weeks depending on queue slots.
Specifications on this page were last reviewed by our engineering team in August 2026.