Looking for tips on scissors knurling.

[D.sebens]

I had a chance to play around with my scissors knurler on some aluminum. I figured I’d go with the most aggressive knurl for my test. Course and tightened it until the knurler was full diamonds. A few thoughts, as I was tightening it you could really hear it groan for oil. It quieted up a lot with oil. I continued to oil as I ran the knurler down. The knurl looks pretty good. Maybe a little bit of galling. If I wanted full diamond peaks should I do it in multiple passes instead of one? I was feeding at .0037” and that seemed okay. Running around 280rpm.

So did I do it okay? Any tips?

 

[woodchucker]

so there are those who say one pass, and others who say more. So you will get many opinions.

I wonder if @darkzero can chime in, as he has done some beautiful knurling on titanium, and that is some hard stuff.

 

[MrWhoopee]

If you want to hear some opinions, post pictures.

 

[D.sebens]

If you want to hear some opinions, post pictures.

Will do. I figured maybe people had some tips but I’ll post my knurl tomorrow.

 

[OTmachine]

One pass, using oil or water soluble coolant. With aluminum, the grade and type does matter as far as machinability. Difficult to pick up knurl for cumulative passes in production .

 

[WobblyHand]

Will do. I figured maybe people had some tips but I’ll post my knurl tomorrow.

It's easier to tell what happened with pictures.

I've had interesting experiences with knurling, everything from too little pressure and not tracking to too much pressure and tear out. I don't knurl enough to remember everything so if I need a knurl I run a similar practice piece just to remember what "just right" feels like. For me it's developing muscle memory to get the right pressure and remembering to use enough cutting oil. You need quite a bit of lube both on the wheel axles and the knurling wheels.

I take my knurler apart before use and make sure the HSS axles well lubricated. Then lube the wheels. Don't forget to wear an apron or crappy shirt, else you will earn your stripes for the day! Yes, I learned the hard way. High sulphur cutting oil has a persistent aroma.

 

[7milesup]

@D.sebens There is a little bit of math behind knurling if you want to dig into it. Most people don't bother with it but here is a link to a website that will walk you through it, just in case you are interested.

 

[OTmachine]

@D.sebens There is a little bit of math behind knurling if you want to dig into it. Most people don't bother with it but here is a link to a website that will walk you through it, just in case you are interested.

Good link! Thanks for posting! Technique is similar to thread rolling, which already has it built into rolls.

 

[D.sebens]

Here’s the knurl

 

[woodchucker]

Here’s the knurl

That's a nice knurl. Nothing to complain about.
That section that looks a little muddled compared to the rest, is not clear as to what happened.
I think that it might be material being re-cut instead of dropping out of the way. That's where I think plenty of cutting fluid comes in. Not only does it lubricate, but it washes away old material.
Other than that, those look pretty good.