Frequently Asked Questions (FAQ)

The general rule is: if it can be cut with a utility knife, it can probably be cut with a Donek Tools Drag Knife.  What follows is a list of materials, we, or our customers, have cut with our Drag Knives.

• Plastics: UHMW Polyethylene, ABS, Lexan Film
• Cardboard: Corrugated and paperboard
• Coroplast (Corrugated plastic sign material)
• Vinyl: Sign and sticker vinyl
• Paper: All kinds
• Foam: Foamboard such as RL Adams Rediboard
• Wood Veneer – we prefer paper backed, but straight veneer works too
• Pre-preg carbon fiber laminates
• Leather (Thin and thick materials work well)
• Fabric: All sorts including dry fiberglass, carbon fiber and kevlar (Special vacuum fixtures may be helpful if you are not using the creaser and rotary cutting blade)
• Gasket Materials

The tip of the blade trails behind the motion of the CNC.  The precision bearings in the tool allow it to freely rotate and act much like the castor on an office chair.

Sharp corners are achieved with what are referred to as corner actions within the CNC tool path.  These corner actions instruct the CNC to raise the blade such that the tip is just barely in contact with the material surface.  The machine then moves through a very small circle around the tip of the blade causing the blade to rotate, while the tip of the blade remains in the same location.  The machine then moves the blade back to the cutting depth and resumes cutting.

No special software is required if you do not need or require sharp corners in your cuts. If you round off or fillet all the corners on the part you intend to cut, you can simply treat the Drag Knife as an engraving bit and cut on your vector/line. Care must be taken when creating your tool path to ensure the tool starts and ends on each cut in the same orientation.

If you want to cut sharp corners in your cut parts or do not wish to worry about blade orientation at the beginning and end of each cut, you will need either SheetCAM, Vectric VCarve Pro 7 and higher, or Vectric Aspire 4 and higher. All of these CAM packages offer drag knife tool path capabilities with corner actions. SheetCAM Offers offset compensation as well making it possible to cut details smaller than the tools offset as well as producing greater precision in your finished part.

The spindle or router does not provide the rotation of the blade. The blade acts as rudder and is oriented by the motion of the machine. For more on this see “How does the blade turn” in the above answer.

The Drag Knife is not balanced for high speed rotation. If you supply power to your router or spindle while it is installed, you could do damage to the router or spindle bearings. Unbalanced spinning objects can also do very unpredictable things causing severe injury to anyone within their vicinity.

There are only 2 requirements for a Donek Tools Drag Knife to work in a CNC machine. It must move in the x, y, and z directions and you must have either a 1/2in or 1/4in collet for holding the tool.

1. Select “Menu” on the hand controller.
2. Select “Utilities”
3. Select “No Spin”
4. Enter tool number
5. Press “enter”
6. Disable “No Spin” by returning tool number to “0”

Special thanks to Dan C. Gartin from Custom Mobility Inc. for this answer