Cut Type Knurling

• This tool can produce a "straight" or a 30º "spiral" knurl.
  
  • Right-handed use: For a straight knurling on the component (RAA) you will need to fit one right-hand spiral knurl (BR30º). For a 30º right-spiral knurling on the component (RBR) you will need to fit one straight knurl (AA).
  • Left-handed use: For a straight knurling on the component (RAA) you will need to fit one left-hand spiral knurl (BL30º). For a 30º left-spiral knurling on the component (RBL) you will need to fit one straight knurl (AA). 
    
    The knurl should be fitted to the holder as shown using a high temperature grease for initial lubrication. Tighten the socket cap screw to ensure the knurl is secured adequately and that it is free to rotate.

• Now clamp the tool into the machine as shown above. Ensure that the top surface of the shank is exactly on centerline of the machine (this will be on the underside surface if mounted upside down on a CNC rear turret.)

• Set the head in a level position and secure tightly by the main socket cap screw (A). Also tighten the two "jacking" screws (B) to prevent any rotation of the head.

• Prepare your knurl blank diameter to suit the knurl being applied. Although this size can theoretically be calculated, trial and error is the preferred way to get best results. For reference purposes you can use the following formula: diameter = [ knurl pitch x #teeth being applied / pi x cos(helix) ]. Once a functional size has been established it should be held within ±0.03 mm (±.001").

• These cut-knurling tools are designed to make a single pass across the material. The depth of this should be 0.5 x pitch of the knurl (i.e. if a 1.0 mm pitch knurl is being used, the cut depth after "touch on" will be 0.5 mm. radially (or 1.0 mm on dia.) Please refer to the recommended feeds and speeds for cut knurling.

• Lubrication / coolant is very important, there should be a good "jet" blast of coolant at both wheels to ensure a quality knurl is achieved. This will prevent wheel seizure by keeping the solid bushes cool and at the same time, will wash the swarf away. Failure to wash away the swarf will result in small particles being rolled into the finished knurl profile thereby reducing the overall quality.

• Method of approach is important. The knurl wheel should be plunged into the end of the workpiece VIA THE X-AXIS (not the z-axis) with an engagement length of 2 x pitch (but no more than 50% of the width of the wheel). It is important to penetrate the part at least 50% of the pitch of the knurl. Once at the correct depth the tool can traverse across the component in the usual way. At the end of traversing the tool should be retracted using the cross slide (X axis at the appropriate position).

• If the resultant knurl has a spiral appearance of less than 5º it can be adjusted using the two jacking screws at the front of the head. If the error is more than 5º it indicates there is a center height problem with the set-up.

• At regular intervals during the production run, make checks to ensure the knurl wheel is free to rotate and that it is not showing excessive signs of wear. 

First, decide if you require a 30º "diamond" knurl or a 45º "cross" knurl on your component. The knurls should be fitted to the holder as shown using a high temperature grease for initial lubrication. Tighten the socket cap screw to ensure the knurls are secured adequately and that they are free to rotate.

Loosen the two pairs of set screws (A) on the top and underside of the head unit. Using an allen key in the back-end of the shaft, rotate both wheel mechanisms independently and set the pointers on the graduated scale to the correct diameter of the workpiece. Re-tighten all four set screws to secure the shafts.

Loosen the two set screws (B) which prevent the head from pivoting slightly. Loosen the main head pivot screw (C) just enough to allow the head to centralize when it touches on the component.

Now clamp the tool into the machine as shown in section 1 above.

Bring the tool down to a position that is just clear of a pre-turned diameter. Turning the chuck by hand, continue to move the cross slide (X Axis) until both knurls centralize and touch the pre-turned diameter at the same time. Leaving the tool where it is, clamp the main head pivot screw (C) and tighten both of the jacking screws (B) to ensure the head is locked up tightly. RE-CHECK THE TOUCH-ON AND REPEAT IF THE KNURLS ARE MORE THAN 0.05 mm OUT. (i.e. if one knurl touches before the other by more than this amount.)

These cut-knurl tools are designed to make just one pass across the material. The depth of this should be 0.5 x pitch of the knurl (i.e. if a 1.0 mm pitch knurl is being used, the cut depth after "touch on" will be 0.5 mm radially (or 1.0 mm on dia.) Please refer to the recommended feeds and speeds for cut knurling (speeds and feeds).

Lubrication/coolant is very important, there should be a good "jet" blast of coolant at both wheels to ensure that a quality knurl is achieved. This will prevent wheel seizure by keeping the solid bushings cool and at the same time will wash the swarf away. Failure to wash away the swarf will result in small particles being rolled into the finished knurl profile thereby reducing the overall quality.

Plunge the tool into the workpiece along the x-axis with an engagement length of 2 x pitch (but no more than 50% of the width of the wheel). It is important that the wheels engage the part coming down the x-axis and not just coming down the z-axis. Once at the correct depth the tool can traverse across the component in the usual way. AT THE END OF TRAVERSING THE TOOL SHOULD BE RETRACTED USING THE CROSS SLIDE (X AXIS AT THE APPROPRIATE POSITION. 

At regular intervals during the production run, make checks to ensure the knurl wheels are free to rotate and that they are not showing excessive signs of wear.