Handmade Vacuum Tube Stem Blank, Soda-Lime Glass, 30mm x 18mm Tube

Glass vacuum-tube stem blank, formed by centrifugation and annealed. Also available in low-profile slot shape.

To use, heat to working temperature, press against Dumet wire assembly and immediately anneal to produce an UHV-tight electrical feedthrough. 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.
• Small End OD: 18mm ±.23 (.709" ±.009)
• End Execution (Large End): Fire-Polished
• End Execution (Small End): Ground
• Length: 30mm ±5 (1.18" ±.196)

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