Knurling how deep? How far do you go?

[WobblyHand]

From watching Joe Pie's video, it seems I have not gone too far. I have not gotten to the point of breaking off the diamonds. I haven't quite formed diamonds yet. That's fine for what I need to do.

The next piece I did was in 12L14. It was just a tommy bar for my ER32 chuck that I had made and wanted to knurl. This bar would get a little greasy when using, so I thought a knurl would help. I knurled 6 inches of the bar. The knurling depth is not even. It is better formed near the tailstock and less so closer to the chuck. I do know my tailstock is not centered vertically with the spindle axis - that is another mini-lathe project. Guess I need to adjust the pressure a little along the way. Nonetheless, the knurl is functional. Machined a couple of grooves to give it a little interest. For some reason my phone isn't uploading the photo. When it's uploaded I'll post it.

 

[Illinoyance]

I disagree with Mr Whoopee. Run the knurl a little longer and possibly more pressure to get the points to fully form.
A fully formed diamond knurl can be uncomfortable to grip so it is better to stop with less than full diamonds. I think your sample is just fine. I would suggest running a file against the finished knurl to remove the sharp edges from the craters.

 

[MrWhoopee]

This discussion has caused me to re-examine what I was taught about knurling and the cause of the craters where the points should be. I was taught that the craters were caused by the points breaking off by feeding in too far. While reading the comments in this thread, I realized that the craters are actually created by material being pushed up from the grooves and rising above the stock surface, surrounding the area where the points will finally be.

You learn something new everyday (with any luck).

 

[Illinoyance]

Knurling looks pretty simple but what is going on between the tool and the work is pretty complex.

 

[Aukai]

There are more things that can go wrong, or not perfect, than can go right.

 

[Illinoyance]

Actually I find it rather easy. I just use a lot of pressure and traverse slowly over the part. If the knurl doesn't track right I use more pressure. I use a lot of cutting oil when knurling.

 

[Christianstark]

I'm a total noob as so far that I have not even received my lathe or mill, but I think those knurls look fantastic. Everything you posted.

I know...low bar, but I am impressed.

 

[Illinoyance]

Christianstark,​

If you use an Aloris style bump knurler the biggest problem will be setting the tool height so both knurls bear equally on the work. If you use a scissor or clamp type too tool height is not an issue.

 

[Aukai]

Tool height no, centering is important though. In aluminum my knurls are 6" long, my SS ones are 2' long. I have a cookie tray under my lathe, and put pig mat down. Cutting oil is expensive, I use a Reilang oil can with ATF, and as the knurler traverses I shoot copious amounts of ATF on the wheels, axles, and the work to float away any metal particles. It also helps keep the axles lubricated with the load on them.

This is just what I have come up with, I did not ask if I was doing it right, so I'd like to hear any comments as well. I have done close to 30 of these, and no 2 look exactly alike, so I'm no expert at all.

 

[Illinoyance]

Nice job. You stopped just short of a full diamond point. That is good.