Heavy duty T-bolt hose clamp: a rolled-edge steel band with a bridge over the gap, closed by one bolt through trunnion rollers, zinc plated with a yellow passivate. Supplied in narrow clamping ranges.
Prices on request. Contact us for availability and quotations.
A T-bolt pattern clamp puts the whole clamping load on one bolt running through two trunnion rollers, so it can be tightened with an ordinary spanner and can be reached in places a worm drive screw cannot. The band edges are rolled so they do not cut the hose cover, and a bridge under the gap keeps the cover from being pinched into the opening. The gold colour that gives the clamp its trade name is a yellow passivate over zinc plating.
No DIN or ISO standard governs T-bolt clamps. They are a manufacturer pattern - Mikalor Supra, NORMA GBS and equivalents - so the clamping range, band width, bolt size and torque all come from the maker's own table rather than from a standard. As a reference, one European supplier lists an all-zinc-plated heavy duty clamp of this pattern in ranges from 17-19 mm up to 294-304 mm, with band widths of 18 to 26 mm and M5 to M10 bolts. It publishes no torque figure for that plated range; for its stainless Supra heavy duty pattern, which runs from 17-19 mm to 395-408 mm, maximum tightening torques run from 10 N m on an 18 mm band with an M6 bolt to 45 N m on a 28 mm band with an M10 bolt.
The same source gives a maximum medium pressure for the Supra pattern that falls with diameter, from 45 bar in the smallest sizes to 6 bar at 162-200 mm and 3 bar from 200-213 mm up to 395-408 mm, and qualifies it as depending on hose type and connection shape. Corrosion class matters as much as size: in the W1 to W5 classification used across this trade, W1 is zinc plated steel throughout - which is what this clamp is - while W4 and W5 are austenitic stainless.
State at order: hose outside diameter over the cover, the clamping range wanted, and the corrosion class.
| Type | T-bolt pattern hose clamp - rolled-edge band with a bridge over the gap, closed by a single bolt through trunnion rollers. The photographed sample has a hexagon head bolt |
|---|---|
| Finish | Zinc plated steel with a yellow passivate throughout, band, bridge and bolt - the W1 corrosion class in the hose clamp classification |
| Standard | None. No DIN or ISO standard governs the T-bolt clamp; it is a manufacturer pattern (Mikalor Supra, NORMA GBS and equivalents), so range, band width, bolt size and torque come from the maker's table |
| Clamping Range (reference) | Supplied in narrow bands. Tubes International lists an all-zinc-plated (W1) heavy duty clamp of this pattern (HDC) from 17-19 mm to 294-304 mm, and the Supra heavy duty pattern from 17-19 mm to 395-408 mm |
| Band and Bolt (reference) | Supra heavy duty pattern: band widths 18, 20, 25 and 28 mm with M6, M7, M8 and M10 bolts. The all-zinc-plated HDC pattern: band widths 18, 20, 22, 24 and 26 mm with M5, M6, M8 and M10 bolts |
| Tightening Torque (reference) | Size dependent, Supra heavy duty pattern only - the HDC pattern publishes no torque: 10 N m on an 18 mm band with M6, 12 N m and 16 N m on a 20 mm band with M7, 30 N m on a 25 mm band with M8 and 45 N m on a 28 mm band with M10 |
| Maximum Medium Pressure (reference) | Supra heavy duty pattern, falls with diameter: 45 bar from 17-19 mm, 40 bar, 36 bar, 28 bar, 20 bar, 12 bar, 9 bar, 6 bar at 162-200 mm and 3 bar from 200-213 mm to 395-408 mm - the supplier qualifies this as depending on hose type and connection shape |
| Corrosion Classes | W1 zinc plated steel throughout; W2 stainless band and bridge with plated steel bolt and rollers; W4 AISI 304 band and bridge with AISI 302 bolt; W5 AISI 316 throughout. NORMA publishes minimum salt spray resistance of 144 h for W1 and 1000 h for W5; the alloy names are trade convention, not NORMA's own statement |
