12 × 8 mm alumina thermocouple protection tube
OD 12 mm · ID 8 mm · wall 2 mm
- Standard size
An alumina sheath that shields the thermocouple wires and their insulator from the furnace atmosphere. We make it closed at one end or open at both, and cut it to the length you order.
Specifications
Nominal dimensions from our factory's standard-size list, September 2026.
| Outside diameter (OD) | 12 mm |
|---|---|
| Inside diameter (ID) | 8 mm |
| Wall thickness | 2 mmcomputed: (OD − ID) ÷ 2 |
| Length | 300–2000 mm |
| Ends | One-end closed · Open-ended |
| Availability | Standard size. Stock covers most standard sizes; the quotation confirms availability |
| Material and grade | High-alumina (>85% Al₂O₃), corundum (99, 99.5 and 99.7% Al₂O₃ grades) and mullite. Purity and maximum temperature are confirmed per SKU. |
Our insulators that fit inside
Insulators from our standard list whose OD is at least 1 mm smaller than this tube's 8 mm ID.
How we worked it out: insulator OD + 1 mm ≤ tube ID, on nominal sizes, which leaves room for the tolerances of both parts. Check the fit against your own drawing.
Tolerances on our 2026 orders
What buyers wrote on the orders we supplied in 2026 for 12 mm OD. They are what was ordered and delivered, not a promise for every order: the tolerance for your order is the one in its quotation.
| Dimension | Tolerance on orders (mm) |
|---|---|
| OD | ±0.5 |
| ID | ±0.5 or +1/−0 |
| Length | ±1 |
Ordering
- Minimum order, non-standard parts
- 100 pcs
- Usually, per item made to your drawing or sample.
- Samples for approval
- 5–10 pcs
- Usually sent for you to approve before the order runs.
- Production lead time
- 25–30 days
- Usual production cycle for non-standard parts.
- Standard sizes from stock
- ~3–7 days
- Stock covers most standard sizes. Small orders ship in about 3 days, bulk orders in about 7 days.
Typical terms. Quantities and dates for your order are confirmed in its quotation.
Nearby sizes
Request a quote
Get a quotation for the 12 × 8 mm protection tube.
Tell us the dimensions, grade and quantity. A contractual datasheet with current, product-specific test data and tolerances comes with each quotation.