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 | BBT (dual-contact face-and-taper) |
|---|---|
| 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 | 10 |
| Brand | Mongtec Precision Inc. |
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 |
|---|---|---|---|---|---|---|---|
| BBT40QHY06Q90 | Ø6 | 26 | 44.5 | 90 | 43 | 30 | M5 |
| BBT40QHY08Q90 | Ø8 | 28 | 44.5 | 90 | 43.5 | 30 | M6 |
| BBT40QHY10Q90 | Ø10 | 30 | 44.5 | 90 | 44 | 34 | M8x1 |
| BBT40QHY12Q90 | Ø12 | 32 | 44.5 | 90 | 44 | 39 | M10x1 |
| BBT40QHY14Q90 | Ø14 | 34 | 44.5 | 90 | 44.5 | 39 | M10x1 |
| BBT40QHY16Q90 | Ø16 | 38 | 50 | 90 | 44.5 | 42 | M12x1 |
| BBT40QHY18Q90 | Ø18 | 40 | 50 | 90 | 44.5 | 42 | M12x1 |
| BBT40QHY20Q90 | Ø20 | 42 | 50 | 90 | 45 | 44 | M12x1 |
| BBT40QHY25Q100 | Ø25 | 57 | 62 | 100 | 54 | 50 | M16x1 |
| BBT40QHY32Q105 | Ø32 | 64 | - | 105 | - | 54 | M16x1 |
The drawing above is the published catalogue drawing, and the dimension letters are the columns of the table below. What Mongtec confirms for you is the interface on your machine, the reach for the operation, and the final article number. Send the machine and the operation; the check is free.
Send my machine and get the article number →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 10 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.