12 SST KNURLING TOOL HOLDERS
   
   

The spindle speed when knurling is much less critical than when turning. A typical starting point is about 100 SFPM. Practical speeds range from about 50 to 150 SFPM. If the knurls become too hot to touch, you should either supply more coolant or slow down the speed. Lower speeds may give longer tool life.

When knurling with a single knurl, the initial infeed rate should be about .002” per revolution (“/rev.). The ideal feedrate may be from .001” to .004” / rev. When plunging only, the part is typically rolled complete in 5 to 20 revolutions of the work. Do not dwell more than 1 or 2 revolutions of the work after reaching full depth. When dwelling or feeding too slowly, the material may tend to work- harden, putting great stress on the knurls, or it may flake, causing a powdery finish.

When knurling with a two-knurl straddle-type holder, the initial infeed rate should be about .010” per revolution (“/rev.). The ideal feedrate may be from .005” to .030” / rev. The feed needs to be much higher because the knurls are not feeding straight into the material, but are feeding tangent to the outer diameter of the part. Again, do not dwell excessively after the center of the part is reached.

If the knurl pattern to be produced is wider than the knurl, then the knurl can be fed axially to make a wider knurl band. The feedrate when feeding axially may be different than when infeeding. A good starting point would be about .010” / rev. The ideal feedrate may range from .005” to .025” per revolution.

      SURFACE FEET to RPM CONVERSION CHART      
Work         Surface Speed (In surface feet per minute)      
Diameter 50 60   70   80 90 100 110   120 130   140
1/16 3,056 3,667   4,278   4,889 5,500 6,112 6,723   7,334 7,945   8,556
1/8 1,528 1,833   2,139   2,445 2,750 3,056 3,361   3,667 3,972   4,278
3/16 1,019 1,222   1,426   1,630 1,833 2,037 2,241   2,445 2,648   2,852
1/4 764 917   1,070   1,222 1,375 1,528 1,681   1,833 1,986   2,139
5/16 611 733   856   978 1,100 1,222 1,345   1,467 1,589   1,711
3/8 509 611   713   815 917 1,019 1,120   1,222 1,324   1,426
7/16 437 524   611   698 786 873 960   1,048 1,135   1,222
1/2 382 458   535   611 688 764 840   917 993   1,070
        APPROXIMATE INCREASE IN KNURLED DIAMETERS
        Using Circular or Diametral Pitch Knurls          
Pitch Tooth   Straight Diagonal   Diamond (ON PART)  
TPI mm Angle   In.   mm In. mm 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
    70°   .014"         .016"          
35 0.73     .36mm .014" .36mm   .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
    Tooth         Diamond (ON PART)  
DP Pitch   Straight Diagonal    
mm Angle   In.   mm In. mm 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 0.5 80°   .009"   .23mm .008" .20mm .009"   .23mm .005"   .13mm
1-800-642-2024 LOCAL 508-755-5302 FAX 508-755-4522 sales@staffordspecialtools.com