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

Straddle Type Holders

Compact Straddle Holders 

Operating Instructions

Inch and Metric Dimensions

Self Centering Bump Holders - Inchh
These holders are compact in design and ideally suited for small CNC and SWISS style machines. Holders are self centering and can easily be adjusted for different diameters by either loosening or tightening the two clamping screws. Good for Axial Feeding with "Convex Inch" or "Convex Metric" knurls. 

 

Heavy Duty Adjustable Straddle Holders

Operating Instructions

Inch and Metric Dimensions

Self Centering Bump Holders - Inchh

These knurl holders are, designed for medium and large lathes, are self centering and very robust. Ideal for heavy axial feeding with convex style knurls. All supplied with carbide pins and set screws.

Note: If you will be axially feeding tools to produce a knurl pattern wider than the tool itself we recommend using "Convex Inch" or "Convex Metric" axial feed style knurls.


Compact Straddle Holders - Setup and Operating Instructions


General Instructions

These holders are designed to fit small CNC machines and Swiss type automatics. They are supplied as right-hand style, but may be reassembled as left-hand style. You can use one right-hand and one left-hand knurl to produce a diamond pattern. Straddle holders may also be traversed to produce long knurl patterns. Convex axial-feed knurls are recommended when traversing. Straddle knurling produces much less work deflection than bump knurling. This allows knurling on longer parts or smaller diameters.


Setting Up

For rolling a "full" straight or diagonal knurl pattern with standard 70°, 80°, or 90° knurls, first determine the proper pre-knurl blank diameter if it is not known. We would normally recommend subtracting the approximate increase in knurled diameter (see Table I) from the approximate maximum finish knurl diameter specified on the drawing. Then your minor diameter would be approximately your just determined blank diameter minus this same roll up amount. 

To make it easier to set up the job, you might want to make a set up pin to put in your machine spindle prior to running your first piece. This pin would be the approximate minor diameter just figured. With the holder open, run it up to the set up pin and then just snug the two arms of the holder against the pin while at the centerline (see determining centerline). Now if you take out the set up pin and put your part in, it should roll up close to full form. A minor adjustment may be necessary to achieve the desired results.

Speeds & Feeds

The recommended speed for knurling is the same speed that you would turn the material being rolled using a high speed steel turning tool. If the knurls get excessively hot, reduce the speed. The feedrate should be from .005" to .015" / revolution. Too low a feedrate causes flaking of the work. Too high may cause excessive feed lines in work and premature knurl failure.


Knurl Adjustment

Adjust the two screws on the top of the holder until the knurls just contact the work. Retract the holder from the work. Tighten the screw closest to the knurls a small amount and make a test roll. Examine the knurl pattern and adjust if necessary.


Changing Knurls

Loosen the set screws locking the knurl pins. Remove the knurl pins, then replace the knurls. Replace the pins and tighten the set screws.


Changing from right-hand to left-hand

Loosen the set screw on top of the mounting shank. Loosen the two screws on top of the holder. Remove the mounting pin that attaches the holder to the shank. Re-install the pin from the opposite side. Insert into the mounting shank from the opposite side and tighten the screws.


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Adjustable Straddle Holders - Setup and Operating Instructions

(Large Capacity, Heavy Duty)


General Instructions

These holders are designed to fit most medium to large size CNC machines, and to roll more difficult jobs. They are supplied as right-hand style, but may be reassembled as left-hand style. You can use one right-hand and one left-hand knurl to produce a diamond pattern. Straddle holders may also be traversed to produce long knurl patterns. Convex axial-feed knurls are recommended when traversing. Straddle knurling produces much less deflection than bump knurling. This allows knurling on longer parts or smaller diameters.


Setting Up

For rolling a "full" straight or diagonal knurl pattern with standard 70°, 80°, or 90° knurls, first determine the proper pre-knurl blank diameter if it is not known. We would normally recommend subtracting the approximate increase in knurled diameter (see Table I) from the approximate maximum finish knurl diameter specified on the drawing. Then your minor diameter would be approximately your just determined blank diameter minus this same roll up amount. 

To make it easier to set up the job, you might want to make a set up pin to put in your machine spindle prior to running your first piece. This pin would be the approximate minor diameter just figured. With the holder open, run it up to the set up pin and then just snug the two arms of the holder against the pin while at the centerline (see determining centerline). Now if you take out the set up pin and put your part in, it should roll up close to full form. A minor adjustment may be necessary to achieve the desired results.

Speeds & Feeds

The recommended speed for knurling is the same speed that you would turn the material being rolled using a high speed steel turning tool. If the knurls get excessively hot, reduce the speed. The feedrate should be from .005" to .015" / revolution. Too low a feedrate causes flaking of the work. Too high may cause excessive feed lines in work and premature knurl failure.


Knurl Adjustment

Adjust the two nuts on the eyebolt until the knurls just contact the work. Retract the holder from the work. Tighten the nut closest to the knurl a small amount, lock the other nut against it and make a test roll. Examine the knurl pattern and adjust again if necessary.


Changing Knurls

Loosen the set screws locking the knurl pins. Remove the knurl pins, then replace the knurls. Replace the pins and tighten the set screws.


Changing from right-hand to left-hand

Loosen the set screw on top of the mounting shank. Remove the mounting pin that attaches the holder to the shank. Re-install the pin from the opposite side. Insert into the mounting shank from the opposite side and tighten the screw.


 

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APPROXIMATE INCREASE IN KNURLED DIAMETERS

Using ACCU TRAK Circular or Diametral Pitch Knurls

TPI
Pitch
mm
Tooth
Angle
Straight
In. / mm
Diagonal
In. / mm
Diamond (ON PART)
Male
Female
12
2.12
90°
.034" / .86mm
.034" / .86mm
.038" / .97mm
.023" / .58mm
16
1.59
90°
.025" / .64mm
.025" / .64mm
.029" / .74mm
.017" /.43mm
20
1.22
90°
.020" / .51mm
.020" / .51mm
.023" / .58mm
.014" / .36mm
25
1.02
90°
.016" / .41mm
.016" / .41mm
.018" / .46mm
.011" / .28mm
30
0.85
90°
.013" / .33mm
.013" / .33mm
.015" / .38mm
.009" / .23mm
35
0.73
90°
.011" / .28mm
.011" / .28mm
.013" / .33mm
.007" / .18mm
40
0.64
90°
.009" / .23mm
.009" / .23mm
.010" / .25mm
.006" / .15mm
-
35
0.73
70°
.014" / .36mm
.014" / .36mm
.016" / .36mm
.009" / .23mm
40
0.64
70°
.012" / .34mm
.012" / .34mm
.013" / .33mm
.008" / .20mm
50
0.51
70°
.009" / .23mm
.009" / .23mm
.010" / .25mm
.006" / .15mm
60
0.42
70°
.007" / .18mm
.007" / .18mm
.008" / .20mm
.005" / .11mm
70
0.36
70°
.006" / .15mm
.006" / .15mm
.007" / .17mm
.004" / .10mm
80
0.32
70°
.005" / .13mm
.005" / .13mm
.006" / .15mm
.004" / .10mm
-
DP
Pitch
mm
Tooth
Angle
Straight
In. / mm
Diagonal
In. / mm
Diamond (ON PART)
Male
Female
64
1.25
80°
.024" / .61mm
.021" / .53mm
.024" / .61mm
.015" / .38mm
96
0.83
80°
.016" / .41mm
.014" / .36mm
.016" / .41mm
.010" / .25mm
128
0.62
80°
.012" / .30mm
.010" / .25mm
.012" / .30mm
.007" / .18mm
160
0.50
80°
.009" / .23mm
.008" / .20mm
.009" / .23mm
.005" / .13mm
             


 

 

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DETERMINING CENTERLINE WITH STRADDLE HOLDERS


With an axial feed holder coming from the turret, the wheels should already be close to the centerline unless the holder is defective.

When using a straddle type holder which comes in from the cross-slide, or x-axis of a cnc machine, the following procedure should enable you to locate the opposing knurling wheels above and below the exact centerline. This is normally preferred to keep spindle forces to a minimum on your machine.

  1. After setting the holder with the proper opening (at the minor diameter), back it off slightly.
  2. Use any flat strip of metal or hard plastic and just touch the two knurling wheels to this strip and the strip to the workpiece blank diameter at the same time.
  3. Now remove the strip and advance the holder by the radius of the knurling wheels (1/2 the diameter of the wheels) + the thickness of the strip used + the radius of the workpiece (1/2 the blank diameter). Now the wheels in the holder will be very close to the centerline.

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