Straight knurling questions

[Chris DentonParticipant @chrisdenton53037]

Do I need to calculate the knurling pitch when straight knurling on a 31.75mm bar?

[Chris DentonParticipant @chrisdenton53037]

[Michael GilliganParticipant @michaelgilligan61133]

No … The knurling will "find" its own pitch

But, of course, the effective diameter will be whatever it turns out to be.

MichaelG.

[jason udallParticipant @jasonudall57142]

Always wondered that..
Then I realised that a medium parallel knurle is say 0.5 mm pitch which translates to 0.08 mm on the diameter…so in any case as Michael says if sorts itself out…

[jason udallParticipant @jasonudall57142]

Btw…you don’t calculate the pitch…its intrinsic to the knurle…what I think you were asking is the start diameter. ..

[Chris DentonParticipant @chrisdenton53037]

Ok, thanks.

So it doesn't matter what size roller I use?

[Tony Pratt 1Participant @tonypratt1]

I believe in theory the work circumference should be exactly divisible by the knurl pitch for a perfect knurl, I did Google the subject and there is a lot of info available.

I have never bothered about precise work start diameters and have ben fairly successful.

Tony

[Michael GilliganParticipant @michaelgilligan61133]

Just go for it, Chris

The knurl is displacing metal, not cutting it.

… it should all sort itself out.

MichaelG.

.

Edit: I should just mention [before anyone else does ] that there is a rather exotic knurling system available that does have a cutting action … but most of us can't afford them.

Edited By Michael Gilligan on 29/07/2014 19:25:24

[Neil WyattModerator @neilwyatt]

I read along article once by someone who claimed to have defeated all known knurling problems by calculating both pitch and infeed with great accuracy.

My experience is that problems are mostly caused by a lack of 'well', just allowing the knurl to 'bite' on one side makes it easy to get it right into the work at the start.

neil

[Roderick JenkinsParticipant @roderickjenkins93242]

Posted by Michael Gilligan on 29/07/2014 19:06:17:

Just go for it, Chris

The knurl is displacing metal, not cutting it.

..

While I agree that you do get displacement, you will probably also generate some swarf – at least that's my experience, especially with brass.

As a matter of interest, when I was making a chuck key recently I used a fine straight knurl in the middle of the 1/4" handle. This increased the diameter by 10 thou and provided a good interference fit in the 1/4" hole.

Rod

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Roderick Jenkins on 29/07/2014 19:43:38:

… you will probably also generate some swarf – at least that's my experience, especially with brass.

.

Fair comment, Rod

"Hard Leaded Engraving Brass" in particular will chip rather than flow.

[i.e. some materials are more suited to knurling than others.]

MichaelG.

[jason udallParticipant @jasonudall57142]

Ok.
Speaking with no expertise beyond making 5000 to 7500 parts a week ,
knurled in a single pass .two wheels. Medium straight knurle
On drawn stock
Size of incoming stock did not once cause any issues with the knurles

That was for over seven years 48 weeks year.
There were metal fines in the knurles ( even with flood coolant).so some metal was cut…
Now the od of the part might have been selected carefully to suit but maybe not.
And yes every single nut was inspected for knurle…so some thing was working.

Edited By jason udall on 29/07/2014 21:10:32

[Michael GilliganParticipant @michaelgilligan61133]

Posted by jason udall on 29/07/2014 21:09:31:

… 5000 to 7500 parts a week

… That was for over seven years 48 weeks year.

.

That's a lot of Knurling, Jason

I bow to your wisdom and experience.

MichaelG.

[jason udallParticipant @jasonudall57142]

Michael.
I don’t know about wisdom.
That was one part so not much experience other than setting the same job a few times… knurles lasted about 6 mo.
Most of those on a non cnc automatic…so depth and so forth set by finish not number.

What I mean is knurling ( well straight knurling) although it seems critical to start with the right diameter..it seems pretty tolerant…
Now thread rolling is a different horse entirely. …did a few hundred thousand of those to….
But when all well, thread rolling is far quicker than screw cutting, (even a dia box).

Back to knurling…parallel or straight knurle…pretty painless…diamond knurles. .trickier……

[Oompa LumpaParticipant @oompalumpa34302]

That is 2100000 knurls I just had to work that one out. But the burning question Jason, were you any good at knurling when you were done?

LMAO!
graham

[jason udallParticipant @jasonudall57142]

2100000. Eh.
Was I any good ?.
Well internal scrap on that part ran at about 0.2%…none from knurle..split equally between part too short.. ( end of bar mis feed) and tapping failure on the nut… ( generally feed rate too high..hydralic rate control thermal thing).
..but as I said, knurling on that job too easy to gain much expertise. ..
Now if you ask about the 10, 000 to 15 000. Per week 1/8 bsf nozzles..those were a bast**..you could get a thread to pas the no go and fail on the go gauge… again my guess would be feed rate and setting on the die box…..but never totally got rid of it..just some times popped up..

Edited By jason udall on 30/07/2014 21:23:28

[Kevin FParticipant @kevinf]

Posted by Michael Gilligan on 29/07/2014 19:06:17:

.

Edit: I should just mention [before anyone else does ] that there is a rather exotic knurling system available that does have a cutting action … but most of us can't afford them.

Edited By Michael Gilligan on 29/07/2014 19:25:24

I'm guessing that would be the tool known as the ' quick knurl '

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Kevin Fenrich on 30/07/2014 22:40:00:

I'm guessing that would be the tool known as the ' quick knurl '

.

Indeed it would, Kevin

For the curious [or tonight's Lotto winner] here is the Instruction Manual.

… We can but dream.

MichaelG.

[Ian S CParticipant @iansc]

There is a thread on the quick cut knurle some where on this site. Ian S C

Edited By Ian S C on 31/07/2014 12:38:46

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