Premium CNC & Router Bits for Precision Cutting

6mm Down-Cut Spiral Bit – 1/4″ Shank (AstraHP Coated)

6mm downcut spiral bit for CNC. Clean top edges in plywood, melamine, and MDF. Ideal for grooves, dados, and back panel work. AstraHP Coated Cut Diameter: 6mm Shank: 1/4″ Length of Cut: 1″ Overall Tool Length: 2-1/2″ Made In USA

6mm Down-Cut Spiral Bit – 1/4″ Shank (AstraHP Coated) - Main image
$26.99 $44.99 In stock

Category: Down-Cut CNC Bits

This 6mm down-cut spiral bit features a 1/4-inch shank and an AstraHP coating, designed for clean, chip-free cuts in CNC routing applications.

  • 6mm cutting diameter with a 1/4-inch shank for compatibility with standard collets.
  • Down-cut geometry helps press material down during routing, reducing tear-out on the top surface.
  • AstraHP coating provides a durable surface finish for extended tool life.
  • Ideal for use with CNC machines where precise, clean edges are required.
  • Available as SKU 425-DNC6MM from BitsBits.com.
Before you pay

Check the method and total at checkout.

When it ships

Allow for processing time as well as the journey to you.

Standard Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

View policy
If you need a refund

Keep your order number and contact the store to start.

Please contact us for the refund processing timeframe before returning an item.

View policy
Delivery costs

Review the cost for your destination and chosen service.

Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

View policy
Returning an item

Check the return conditions before sending anything back.

United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.

View policy

Customer Reviews (5.0 / 5 · 5 reviews)

Sophia ★★★★★

The 1/4-inch shank made swapping it into my router collet quick, and the down-cut design left zero tear-out on the plywood edges. Cuts stay clean even after a few hours of use, which is exactly what I needed for my cabinet work.

Grace ★★★★★

The AstraHP coating is holding up way better than the uncoated bits I’ve burned through, and the 6mm cut diameter leaves edges so clean I barely need to sand. Even on a deep pass, the down-cut spiral keeps the top surface chip-free.

Henry M. ★★★★★

First pass on a piece of maple plywood and the down-cut geometry left absolutely zero tear-out on the top surface. The AstraHP coating seems to be holding up well after a few hours of run time with no noticeable wear on the cutting edges.