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Extension socket MK 4 / 4
Extension socket MK 4 / 4 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
At Krollit, we guarantee a safe and reliable shipping process. Orders are handled with the utmost care and traceability until delivery.
For international shipments, please send your request via the dedicated contact form.
Upon delivery, always sign the delivery note with the words “subject to inspection” to allow for proper handling of any irregularities or discrepancies in the product.
Our goal is to ensure you receive prompt service and a worry-free shopping experience.
Extension socket MK 4 / 4
Description
Morse taper extension sleeve MT 4/4 — tool holder MT 4 in machine seats MT 4. Fully hardened, internal and external taper ground according to DIN 2187. Made in Austria, distributed in Italy by Krollit — official Bernardo distributor since 2007.
- External taper: MT 4
- Internal taper: MT 4
- Standard: DIN 2187
- Workmanship: Fully hardened, ground taper
Logistics
Original spare parts available with 3–5 working days shipping. Customer service in Italian available.
Technical specifications
Technical specifications
| Specification | Value |
|---|---|
| External taper (machine) | MT 4 |
| Internal taper (tool) | MT 4 |
| Standard | DIN 2187 |
| Workmanship | Fully hardened, ground taper |
Warranty
Warranty terms and support procedures are available on the dedicated Krollit page.
View Krollit warranty termsFAQ / Frequently asked questions
Frequently Asked Questions
What is an MT 4/4 extension sleeve for and when is it needed?
The MT 4/4 extension sleeve has an MT 4 external taper (fits into the machine) and an MT 4 internal taper (holds the tool). It allows you to mount tools with an MT 4 Morse taper shank on machines with an MT 4 Morse taper seat — the larger number is the machine's taper, the smaller is the tool's taper. The extension sleeve allows the smaller tool to fit into the larger seat, maintaining DIN 2187 concentricity.
Difference between extension sleeve and reduction sleeve?
The extension sleeve fits a smaller taper (tool) into a larger seat (machine): MT 4/4 → the machine has MT 4, the tool has MT 4. The reduction sleeve does the opposite — it fits a larger taper into a smaller seat. They are not interchangeable. Always check which one you need before purchasing.
How do you remove the sleeve from the Morse taper seat?
Using the extractor pin (drawbar) that slides into the spindle hole: insert the pin from the opposite side and strike with a hammer. Alternatively, use the flat extraction wedge inserted into the spindle slot. Never force it with improvised tools — the Morse taper is self-locking and lateral force can damage the seat.
Delivery times?
Original spare parts available with 3–5 working days shipping. Customer service in Italian available.
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