BT40 MAS 403 Whistle Notch holder (DIN 1835 E) Ø6–40 mm
Shipping costs are not included in the price.
Shipping costs are not included in the price.
Weekly deals
5-axis vise with hard jaws
Self-centering machine vise. Hard jaws included.
excl. VAT
Regular price:
Lowest price in the 30 days before the reduction:
Time left
Offer ends 06.11.2026 23:59. Offer applies to the vise + hard jaws bundle only.
Ask about the product
The administrator of personal data is Kortools. We process it to respond to your inquiry. More information regarding the processing of personal data can be found in privacy policy.
Select a product variant:
Individual variants may differ in price
Product code: 8D2D-88163
Product description
BT40 MAS 403 Whistle Notch holder (DIN 1835 E), Ø6–40 mm
Whistle Notch milling holder with a BT40 (MAS 403 BT / JIS B 6339) taper. The tool is clamped by a shank flat inclined at 2° (Whistle Notch, DIN 1835 E) and a clamping screw. The tool shank must have a Whistle Notch flat.
Available bore diameters: 6, 8, 10, 12, 14, 16, 18, 20, 25, 32 and 40 mm. Length L = 50 mm (Ø6 and Ø8), 63 mm (Ø10–20), 90 mm (Ø25), 100 mm (Ø32) and 120 mm (Ø40). Select the variant when purchasing.
Applications
- clamping end mills and drills with a Whistle Notch shank (flat inclined at 2°, DIN 1835 E)
- milling and drilling with secure, rigid clamping by a clamping screw
- CNC milling machines and machining centres with a BT40 spindle (MAS 403 BT)
Specification
| Taper type | BT40 (MAS 403 BT / JIS B 6339) |
| Tool clamping | Whistle Notch: shank flat inclined at 2° and clamping screw |
| Bore diameter d | 6–40 mm (depending on variant) |
| Clamping screws | 1 screw (Ø6–20 mm) or 2 screws (Ø25–40 mm) |
| Coolant | AD version (central coolant supply) |
| Holder runout | ≤ 0.005 mm |
| Balance grade | G6.3 at 15,000 rpm |
| Material | alloyed case-hardened steel (carburized depth 0.8 ± 0.2 mm) |
| Hardness | HRC 56–60 |
| Taper | taper tolerance < AT3, surface roughness Ra < 0.2 µm |
| Standard | MAS 403 BT / JIS B 6339 (taper), DIN 1835 E (Whistle Notch bore) |
Balance grade: G6.3 at 15,000 rpm. If you need a finer balance grade (G2.5) for higher speeds, write to us before purchasing.
Coolant: AD version (coolant through the spindle centre). If your spindle supplies coolant through the flange (form B), write to us before purchasing.
Dimension table
| Variant | d [mm] | D [mm] | L [mm] | M (screw) | Number of screws |
| BT40-SLB06-50 | 6 | 25 | 50 | M6 | 1 |
| BT40-SLB08-50 | 8 | 28 | 50 | M8 | 1 |
| BT40-SLB10-63 | 10 | 35 | 63 | M10 | 1 |
| BT40-SLB12-63 | 12 | 42 | 63 | M12 | 1 |
| BT40-SLB14-63 | 14 | 44 | 63 | M12 | 1 |
| BT40-SLB16-63 | 16 | 48 | 63 | M14 | 1 |
| BT40-SLB18-63 | 18 | 50 | 63 | M14 | 1 |
| BT40-SLB20-63 | 20 | 52 | 63 | M16 | 1 |
| BT40-SLB25-90 | 25 | 65 | 90 | M18×2 | 2 |
| BT40-SLB32-100 | 32 | 72 | 100 | M20×2 | 2 |
| BT40-SLB40-120 | 40 | 80 | 120 | M20×2 | 2 |
d – bore diameter (tool shank), D – body diameter, L – length from the flange face (spindle side) to the holder front face, M – clamping screw thread.
Read the complete designation of the selected variant. For example, BT40-SLB16-63 means a BT40 taper, a Whistle Notch (SLB) holder for a Ø16 mm shank and length L = 63 mm.
How to select
- Check that the spindle has a BT40 interface (MAS 403 BT), not SK40.
- Bore diameter d = tool shank diameter (e.g. an end mill with a Ø16 shank = variant SLB16).
- The shank must have a Whistle Notch flat inclined at 2° (DIN 1835 E). For Weldon shanks (DIN 1835 B) choose a Weldon holder.
FAQ
Will it fit my machine?
The holder has a BT40 taper to MAS 403 BT (JIS B 6339). Before purchasing, confirm that the standard, size and pull stud match the machine spindle requirements. BT40 and SK40 are different tapers, so the designation “40” alone is not sufficient to confirm the selection.
How does it differ from a Weldon holder?
The clamping flat of a Whistle Notch shank is inclined at 2° (DIN 1835 E), while a Weldon flat is parallel to the axis (DIN 1835 B). Choose the holder that matches the tool shank.
Which tools can be clamped?
Tools with a Whistle Notch shank (DIN 1835 E) whose diameter equals d of the selected variant, e.g. end mills or drills.
Select a pull stud
For a BT holder compare BT pull studs in the appropriate size.
Confirm the selection against the spindle requirements: head profile and angle, thread, length, bore and seal.
Bestsellers
-
Bestseller
JCD modular drill with replaceable tip - internal cooling, for deep holes | GrotXD
JCD C20-100-3D Ø10~10.9 JCD C20-110-3D Ø11~11.9 JCD C20-120-3D Ø12~12.9 JCD C20-130-3D Ø13~13.9 JCD C20-140-3D Ø14~14.9 + 61 morePrice €69.52Price €56.52without VAT -
Price €17.09Price €13.90without VAT
-
Price €7.07Price €5.74without VAT
-
Price €7.52Price €6.12without VAT
-
Bestseller
Other Accessories 0.00CNC Chip Fan / Chip Blower
Complete CNC chip fan Kit: blades, springs, pins and screwsPrice €53.56Price €43.55without VAT -
Bestseller
Ball Nose End Mills 0.002-Flute Carbide Ball Nose End Mill - HYPERCUT
Ø1xR0.5x4Dx50L Ø1.5xR0.75x4Dx50L Ø2xR1x4Dx50L Ø2.5xR1.25x4Dx50L Ø3xR1.5x3Dx50L + 26 morePrice €10.09Price €8.21without VAT -
Bestseller
2-Flute End Mills 0.002-Flute Carbide End Mill for Aluminium
Ø1x3x4Dx50L Ø1.5x4x4Dx50L Ø2x6x4Dx50L Ø2.5x7.5x4Dx50L Ø3x9x3Dx50L + 31 morePrice €5.33Price €4.33without VAT -
Bestseller
2-Flute End Mills 0.002-Flute Carbide End Mill for Steel 55 HRC - TiSiN - Solid Carbide
Ø6x24x6Dx75L Ø8x25x8Dx75L Ø4x20x4Dx100L Ø5x30x5Dx100L Ø6x30x6Dx100L + 31 morePrice €4.38Price €3.56without VAT -
Bestseller
Ball Nose End Mills 0.002-Flute DLC Coated Carbide Ball Nose End Mill| DuraEdge Alu
Ø1.0xR0.5x4Dx50L Ø1.5xR0.75x4Dx50L Ø2.0xR1x4Dx50L Ø2.5xR1.25x4Dx50L Ø3.0xR1.5x3Dx50L + 34 morePrice €7.85Price €6.38without VAT -
Bestseller
2-Flute End Mills 0.002-Flute End Mill for Aluminium | VHM | Miniature Ø0.3 - Ø0.9
Ø0.3x2x4Dx50Lx2T Ø0.3x3x4Dx50Lx2T Ø0.3x4x4Dx50Lx2T Ø0.4x2x4Dx50Lx2T Ø0.4x3x4Dx50Lx2T + 28 morePrice €7.95Price €6.47without VAT -
Bestseller
Ball Nose End Mills 0.002-Flute TiSiN Coated Carbide Ball Nose End Mill
Ø1xR0.5x4Dx50L Ø1.5xR0.75x4Dx50L Ø2xR1x4Dx50L Ø2.5xR1.25x4Dx50L Ø3xR1.5x3Dx50L + 38 morePrice €7.24Price €5.89without VAT -
Bestseller
3-Flute Carbide Corner Radius End Mill for Aluminium| AL DLC
Ø1xR0.1x4Dx50L Ø1xR0.2x4Dx50L Ø1xR0.3x4Dx50L Ø1.5xR0.1x4Dx50L Ø1.5xR0.2x4Dx50L + 137 morePrice €5.89Price €4.79without VAT -
Bestseller
3-Flute End Mills 0.003-Flute Carbide End Mill VHM Z-3 for Aluminium| TriMill AL
Ø1x3xD4x50L Ø1.5x5x4Dx50L Ø2x6x4Dx50L Ø2.5x8x4Dx50L Ø3x9x3Dx50L + 41 morePrice €5.08Price €4.13without VAT -
Bestseller
Countersinks 0.003-Flute Countersink Fi4.5-fi60, 90° - HSS-CO - 5% Kobaltu | Straight Shank
Ø4.5 x 4 x 90° x 40L Ø5 x 5 x 90° x 45L Ø6.3 x 5 x 90° x 45L Ø8.3 x 6 x 90° x 50L Ø10.4 x 6 x 90° x 50L + 12 morePrice €4.79Price €3.89without VAT -
Bestseller
3-Flute End Mills 0.003-Flute DLC Coated Carbide End Mill | TriMill DLC AL
Ø1x3x4Dx50L Ø1.5x5x4Dx50L Ø2x6x4Dx50L Ø2.5x8x4Dx50L Ø3x8x3Dx50L + 38 morePrice €5.05Price €4.10without VAT -
Bestseller
3-Flute End Mills 0.003-Flute HRC65 DLC Coated Carbide End Mill, U-Shaped Flute, for Aluminium | DuraEdge3 Alu
Ø1x3x4Dx50L Ø1.5x5x4Dx50L Ø2x6x4Dx50L Ø2.5x8x4Dx50L Ø3x9x3Dx50L + 40 morePrice €6.73Price €5.47without VAT
