Turning one clamping screw with a hex key pressurises a sealed fluid chamber inside the holder body. The pressure expands a thin steel sleeve uniformly around the tool shank, gripping it concentrically along the full clamping length. Release the screw and the sleeve returns — the tool comes out.
Two things follow from that. The fluid layer between body and sleeve damps vibration, which is why hydraulic chucks are the usual choice for reaming, boring and finishing where surface finish matters. And because clamping is mechanical, tools change at the machine in seconds with no heating unit, no cooling wait and no consumables.
| Shank | CAT / ANSI-ASME B5.50 (ISO 7/24) |
|---|---|
| Clamping | Hydraulic expansion sleeve, single hex-key screw |
| Bore range | Ø6 – Ø32 mm (reduction sleeves for intermediate shanks) |
| Best for | Reaming, boring, finish milling, vibration-sensitive work |
| Article numbers | 20 |
| Brand | Mongtec Precision Inc. — Taiwanese brand, designed and engineered in Taichung, Taiwan |
d = tool bore · D = nose diameter · D1 = body diameter · L = gauge length · L1, L2 = clamping and body lengths · G = clamping-screw thread.
| Article no. | Bore Ø d | D | D1 | L | L1 | L2 | G |
|---|---|---|---|---|---|---|---|
| CAT40QHY06Q81 | Ø6 | 26 | 49.5 | 81 | 30 | 27 | M5 |
| CAT40QHY08Q81 | Ø8 | 28 | 49.5 | 81 | 30 | 27 | M6 |
| CAT40QHY10Q81 | Ø10 | 30 | 49.5 | 81 | 31 | 32 | M8x1 |
| CAT40QHY12Q81 | Ø12 | 32 | 49.5 | 81 | 31.5 | 37 | M10x1 |
| CAT40QHY16Q81 | Ø16 | 38 | 49.5 | 81 | 33 | 42 | M12x1 |
| CAT40QHY20Q81 | Ø20 | 42 | 49.5 | 81 | 34 | 42 | M10x1 |
| CAT40QHY25Q81 | Ø25 | 55 | 66 | 81 | 22 | 48 | M16x1 |
| CAT40QHY32Q81 | Ø32 | 63 | 80 | 81 | 25.5 | 55 | M16x1 |
| CAT40QHY06Q110 | Ø6 | 26 | 49.5 | 110 | 29.5 | 27 | M5 |
| CAT40QHY08Q110 | Ø8 | 28 | 49.5 | 110 | 30 | 27 | M6 |
| CAT40QHY10Q110 | Ø10 | 30 | 49.5 | 110 | 31 | 32 | M8x1 |
| CAT40QHY12Q110 | Ø12 | 32 | 49.5 | 110 | 31.5 | 37 | M10x1 |
| CAT40QHY16Q110 | Ø16 | 38 | 49.5 | 110 | 33 | 42 | M12x1 |
| CAT40QHY20Q110 | Ø20 | 42 | 49.5 | 110 | 34 | 42 | M16x1 |
| Article no. | Bore Ø d | D | D1 | L | L1 | L2 | G |
|---|---|---|---|---|---|---|---|
| CAT50QHY06Q81 | Ø6 | 26 | 49.5 | 81 | 30 | 27 | M5 |
| CAT50QHY08Q81 | Ø8 | 28 | 49.5 | 81 | 30 | 27 | M6 |
| CAT50QHY10Q81 | Ø10 | 30 | 49.5 | 81 | 32 | 32 | M8x1 |
| CAT50QHY12Q81 | Ø12 | 32 | 49.5 | 81 | 35 | 37 | M10x1 |
| CAT50QHY16Q81 | Ø16 | 38 | 49.5 | 81 | 40 | 42 | M12x1 |
| CAT50QHY20Q81 | Ø20 | 42 | 49.5 | 81 | 40 | 42 | M16x1 |
Source: Mongtec Hydraulic Tooling System catalogue, Ver 2026.
With a hex key. Turning the clamping screw pressurises the internal chamber and expands the sleeve onto the shank. No heating unit, no external equipment.
Hydraulic damps vibration and needs no equipment to change tools — it suits reaming, boring and finishing. Shrink fit is slimmer and stiffer for deep cavities and very high speed. Mongtec publishes both — see shrink fit chucks.
Ø6 to Ø32 mm across 20 published article numbers, in several gauge lengths per bore.
Send the spindle interface, the tool shank diameters you run and the reach you need. Dimensioned drawings are supplied by email once the enquiry is open.