Knurling how deep? How far do you go?

WobblyHand

WobblyHand

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So mostly finished making my copy of @mikey 's straddle knurler. Of course a knurler deserves a knurled knob to adjust it. So I made one out of 1144. I used sulfur cutting oil which is kind of stinky, but it worked well. I was looking at the knurl and wondering how deep it really should be. How much of a point (or non-point) should there be? The knob I made has little craters rather than a point. Points would be uncomfortable, but what should a decent knurl look like (and maintain good knurling wheel life)?
PXL_20210625_193010798.jpg
This knurl is on 1.25" OD 1144, skimmed to remove the dull finish then knurled with a straddle knurler. Done with FORM ROL EQL 225 wheels. Do I need to apply a little more pressure? I'm obviously not going to throw out the knob, (it's perfectly useful and decent) but I'd like to know for the next knurl what to target.
 
The craters indicate that you've exceeded maximum depth. The points get crushed and broken off. Take a skim cut and another pass with the knurler if you like.
 
I've made a few knurls I usually go by feel. If your fingers grip well , leave it alone.
I'm sure there is some mathematical formula that some engineer came up with, and someone may post it.
 
Hmm, does someone have a picture of a good knurl? Not really sure what it should look like. I did a previous knurl in aluminum and wasn't sure if that was deep enough. Maybe it was too deep. But if I look at the left edge, is that too deep, or not enough?
PXL_20210625_204111767.jpg
Guess I need to try knurling at various pressures and see what happens.
 
Knurling, if brought up sharp can be uncomfortable to grip; having said that, I generally bring it up sharp and then give it a light filing or emery cloth to dull it a bit. There is nothing wrong with a light pass of knurl such as was done on the aluminum, it would be appropriate for something that was going to be pulled against with some force, but not sharp enough to do damage to the hand.
 
One thing to keep in mind is that diametral pitch knurls work best on nominal diameters and circular pitch knurls work best on odd diameters, that is they tend to not double track at the start. I start the knurl at perhaps half the width of the knurl with lots of pressure to get it tracking properly, then start travel.
 
In aluminum, you'll know when you went too deep, it rips the diamonds out by the roots. A friend told me so :rolleyes:
 
I like to make my knurls deep to a point then use a powered wire wheel as if I am cleaning out the valleys.
I go in both directions to ensure they are clean and this smooths them enough to be comfy.
I mainly knurl stainless.
 
Knurling is usually done for grips of different kinds or to increase diameter but for decorative use it can look good knurling deep then skimming off the tops lower with a lathe cutter. Sometimes down to the diamond shapes only or what you think looks good.
 
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