knurltec.com - Pressure knurling

1. Tool adjustment
Ensure that the knurls rotate freely over the shaft. Prior to this operation, it is advisable to apply graphite grease to the moving sections of these parts. Loosen screws "A" locking out the knurl-holder arms "B" and screw "A1" locking out the centring unit "C". Secure the tool on the turret of the lathe. Open the knurl-holder arms "B", and rotate the tapped spindle "D" until the distance between the knurls is greater than the diameter of the part to be knurled. With the lathe chuck at low rpm, move the tool along the X axis until the knurls are perfectly aligned with the vertical plane of the part to be knurled (Figure 1). Once alignment has been completed, close the knurl-holder arms "B", and rotate the tapped spindle "D" until the two knurls make contact with the part and start to rotate. Without removing the knurler, tighten screw "A1" to lock out the centring unit "C". Whilst the part is rotating and the knurls have made contact with the surface of the part, rotate the tapped spindle "D" so that the knurl-holder arms "B" close, the knurls slightly mark the part and the process continues until the required knurl marking has been completed. Normally diameter distance is equal to 50% of the pitch of the knurls used. For example, if a 2 mm. knurl pitch is to be carried out, depth must be 1 mm. (or 0.5 mm. radius). Once the required knurling depth has been reached, secure screws "A" locking out the knurl-holder claws, and remove the tool

2. Starting the knurling process
With the lathe chuck rotating as per the conditions recommended in the tables, move the tool radially (X axis) until the knurls have been aligned with the vertical plane of the part (Figure 1) with no interruptions, radial movement 0.02 - 0.04 mm. / rotation. Then move the tool longitudinally (Z axis) to carry out knurling along the entire length, using the movements set out in the tables. To remove chips, ease the cutting process, cool the operation and lubricate the knurls, this must be carried out using a considerable pressurised flow of coolant, taladrine or cutting fluid.
3. Precautionary measures
The direction of operations must always be towards the knurler unit, and never towards the narrow section of the knurl-holder arm or towards the washer sealing off the knurls (ref. M20). The knurl unit must never be moved backwards with the knurls over the part in retouch mode. The pitch of the knurling operation does not depend on either movements of the tool or the cutting speed. The distance from the base of the slotting which secures the tool to the shaft of the tailstock-head unit must be as marked on the handle of the tool used .
4. Corrections
Grooves to different depths:
	-The knurls are not working to the same depth over the part. Repeat the centring process for the knurl-holder arms "B" with respect to the part to be knurled.
Double knurls:
	- Only slight radial movement when knurling starts.
The knurls break easily:
	- Excessive knurling depth.
Excessive knurl wear:
	- Operating conditions are not correct. Check cutting speed and axial movements.