Knurl Holders

Bump Knurl Holders

Self Centering Bump Holders

Straddle Type

2 Die End Rolling

3 Die End Rolling

Conical Knurling

Taper Knurling Holders

Face Knurling

Shank Conical Knurling Dies

Internal Knurling

Cut Type Knurling

Cut Type Knurling

Cut Type Knurl Holders
CUT TYPE Knurling is not widely used in U.S. market, but common in the rest of the world. The knurling dies are skewed (layed over 30°) to the work piece axis creating a cutting action rather than a forming process. Often times when knurling non-ferrous material (aluminum, brass, etc.) the forming action work hardens the material causing the crest to become brittle and break off. Not so with the cut type knurl - the milling action leaves a sharp solid crest for a perfect knurl.

There are both single and two die holders available. Interesting is the fact that to get the diamond pattern two straight tooth dies are used (on a two die holder) and for a straight pattern a single helical die is used. It is believed that the diameter of a finished knurled part can be more easily controlled with this method; just remember you aren't increasing the diameter of the work piece. Holder shanks can be mounted at right angle to the piece and always use plenty of coolant to wash away chips.

It's best to experiment with the Speeds & Feeds to get the best looking knurl, but generally a feed in the range of 0.07-0.2 mm/rev and a surface speed of 15-55 m/min will work. With softer metals (aluminum & brass) stay on the high end, but with stainless and other high alloys use the lower end. For stainless steel, or other higher alloyed steels, you should expect lower wheel life than that obtained with "forming" wheels

With a fairly rapid infeed to the final minor diameter of the workpiece, cut type knurls will normally track on any diameter. If not, a small variation to the infeed rate, or blank diameter will normally correct any problem. Once established, the blank diameter should be held within +/- .025mm (.001"). Depth of the cut should be .5-.6mm x pitch. The method of approach is very important to getting a good looking knurl. On the end of the work piece, approximately 1-2 pitches wide, plunge the tool straight into the part. After reaching the correct depth then traverse across the part. Note: Do not just feed axially.

Single Knurl Holders

Setup Instructions for Single Wheel Cut Knurling

Inch and Metric Dimensions

Single Knurl Holders

These knurling tools will produce a straight knurl using a 30° RH diagonal knurling die or a 30° RH diagonal knurl with a straight knurling die. The knurl depth should be approximately 50% of the knurl pitch. Surface speed is in the range of 50-200 ft/min (depending upon material) with a feed rate of around .005"/Rev. If the knurl is not parallel, adjust the head. Be sure to use plenty of coolant to flush away the chips.

*Each time the wheels are changed, a high pressure graphite based lubricant should be applied to the bore andbushing to reduce the likelihood of the wheel seizing on the bushing.

 

Double Knurl Holders

Setup Instructions for Double Wheel Cut Knurling

Inch Dimensions

Double Knurl Holders

These knurling tools will produce a 30° diamond pattern using two straight knurling dies. Set the work diameter on the tool scale by unlocking the socket head screws from the rear and tapping to break the lock. The tool has to be mounted in the machine on center. Use the fine adjustment screws to insure both knurls are hitting equally. The depth of cut should be approximately 50% of the knurl pitch and feed at around .005"/Rev. Surface speed should be in the range of 50-200 ft/min depending on material. Always have plenty of coolant flushing the work area.

*Each time the wheels are changed, a high pressure graphite based lubricant should be applied to the bore andbushing to reduce the likelihood of the wheel seizing on the bushing.

 

Replacement Parts for Cut Type Holders 

 

 

Regular Compact Two Die Holders
 

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SINGLE KNURL CUT TYPE HOLDERS
Straight knurling RAA
Right-hand knurl BR 30
Right-spiral RBR 30°
Straight knurl AA
Left-spiral RBL 30°
Straight knurl AA
Straight knurling RAA
Left-hand knurl BL 30°

  • 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. 

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DOUBLE KNURL CUT TYPE HOLDERS
Diamond knurl RGE 30°
Upper axle straight knurl AA
Lower axle straight knurl AA
Cross knurl RGE 45°
Upper axle left hand knurl BL15°
Lower axle right hand knurl BR15°

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.

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Speeds and Feeds for Cut Knurling

Material
Knurl 
Diameter
(mm)
Workpiece Diameter 
2-12 mm
Workpiece Diameter 
12-40 mm
Workpiece Diameter 
40-250 mm
speed
m/min
ft/min
feed
mm/rev
in/rev
speed
m/min
ft/min
feed
mm/rev
in/rev
speed
m/min
ft/min
feed
mm/rev
in/rev
Mild Steel 
up to 60 kg
8.9
14.5 / 15
21.5 / 25
35
115
45
148
60
197
0.05-0.08
.002-.003
0.07-0.09 
.003-.004
0.07-0.15 
.003-.006
-
-
40
131
60
97
-
-
0.07-0.09
.003-.004
0.07-0.09
.003-.006
-
-
-
-
50
164
-
-
-
-
0.07-0.15
.003-.006
Tool Steel 
up to 90 kg
8.9
14.5 / 15
21.5 / 25
25
82
35
115
50
164
0.04-0.07
.002-.003
0.06-0.08
.002-.003
0.06-0.12
.002-.005
-
-
30
98
45
148
-
-
0.06-0.08
.002-.003
0.06-0.12
.002-.005
-
-
-
-
40
131
-
-
-
-
0.06-0.12
.002-.005
Stainless Steel
8.9
14.5 / 15
21.5 / 25
22
72
30
98
40
131
0.04-0.06
.002-.002
0.06-0.08
.002-.003
0.06-0.12
.002-.005
-
-
28
92
35
115
-
-
0.06-0.08
.002-.003
0.06-0.12
.002-.005
-
-
-
-
32
105
-
-
-
-
0.06-0.12
.002-.005
Brass 58
8.9
14.5 / 15
21.5 / 25
60
197
70
230
90
295
0.06-0.10
.002-.004
0.08-0.12
.003-.008
0.08-0.20
.003-.008
-
-
60
197
90
295
-
-
0.08-0.12
.003-.005
0.08-0.20
.003-.008
-
-
-
-
80
262
-
-
-
-
0.08-0.20
.003-.008
Brass 60
8.9
14.5 / 15
21.5 / 25
50
164
60
197
90
295
0.05-0.09
.002-.004
0.06-0.10
.002-.004
0.07-0.15
.003-.006
-
-
60
197
90
295
-
-
0.06-0.10
.002-.004
0.07-0.15
.003-.006
-
-
-
-
80
262
-
-
-
-
0.07-0.15
.003-.006
Bronze
8.9
14.5 / 15
21.5 / 25
35
115
45
148
60
197
0.05-0.08
.002-.003
0.07-0.09
.003-.004
0.07-0.14
.003-.006
-
-
40
131
60
197
-
-
0.07-0.09
.003-.004
0.07-0.14
.003-.006
-
-
-
-
55
180
-
-
-
-
0.07-0.14
.003-.006
Aluminum
8.9
14.5 / 15
21.5 / 25
60
197
70
230
90
295
0.06-0.13
.002-.005
0.08-0.18
.003-.007
0.10-0.25
.004-.010
-
-
70
230
80
262
-
-
0.08-0.18
.003-.007
0.10-0.25
.004-.010
-
-
-
-
70
230
-
-
-
-
0.10-0.25
.004-.010
Grey Iron
8.9
14.5 / 15
21.5 / 25
22
72
30
98
40
131
0.04-0.06
.002-.002
0.06-0.08
.002-.003
0.06-0.12
.002-.005
-
-
28
92
35
115
-
-
0.06-0.08
.002-.003
0.06-0.12
.002-.005
-
-
-
-
32
105
-
-
-
-
0.06-0.12
.002-.005
Cast Iron
8.9
14.5 / 15
21.5 / 25
25
82
35
115
50
164
0.04-0.07 
.002-.003
0.06-0.08
.002-.003
0.06-0.12
.002-.005
-
-
30
98
45
148
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