Handmade Vacuum Tube Stem Blank, Soda-Lime Glass, 30mm x 20mm Slot

Glass vacuum-tube stem blank, formed centrifugally, pressed to a slot shape, ground to length and annealed. Also available in longer tube shape.

To use, heat to working temperature, press against Dumet wire assembly and immediately anneal to produce an UHV-tight electrical feedthrough. then fuse against our matching 30mm envelope to produce a complete vacuum tube.

Our blanks are inspected individually. We guarantee reliable, stress-free fusing against our other soda-lime glass items.

• Material: Soda-Lime Glass (Schott AR-Glas®; Hydrolitic Class 3)
• Wall Thickness: 1.5mm ±.06 (.059" ±.002)
• Large End OD: 30mm (1.18") min.
• Slot End Length: 20mm ±3 (.787" ±.11)
• Slot End Width: 6mm ±3 (.236" ±.11)
• End Execution (Large End): Fire-Polished
• End Execution (Slot End): Ground
• Length: 20mm ±3 (.787" ± .11)

® AR-Glas is a registered trademark of Schott AG.