Knurling question

[john barnes 4Participant @johnbarnes4]

Hi all, I am John from Wigan and this is my first post. I have a question which I hope someone can help with. I have made a knurling tool with 21 tpi knurls. As I work in mm I have converted this to a pitch of 1.2095 by dividing 25.4 by 21. Am I right to assume that to get the knurls to track properly I need to choose a circumference which is divisible by 1.2095? Thanks in advance john.

[john barnes 4Participant @johnbarnes4]

[john carruthersParticipant @johncarruthers46255]

That makes logical sense doesn't it? However I find that with diamond knurls at least, it makes little or no difference.
Just put on a good depth and it 'self rights'. They soon start tracking into the pattern.
I have a small clamp type with medium knurls. I offer it up to the work so the knurls just touch,back off, apply a copious amount of oil then put on say half a turn and bring it onto the work, then run it along as necessary.
Never had a problem with double cuts or skipping.
If it doesn't look right tighten it up a fraction.
They seem to raise material just as much as cutting into the surface.

Edited By john carruthers on 02/06/2017 08:29:36

[Thor 🇳🇴Participant @thor]

Hi John B.,

Welcome to the forum. I have the same experience as John C. when it comes to knurling. Knurling has been discussed before, here are a few links that may be of help:

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Thor

Edited By Thor on 02/06/2017 08:39:17

[Neil WyattModerator @neilwyatt]

Hello John,

Welcome to the forum!

Between the top and bottom of a knurl pattern there are generally three different whole numbers of 'knurls' that will fit around a bar. This means that as long as you start with a decent depth of cut it will 'self align', problems only arise if you only apply a light cut.

Neil

[john barnes 4Participant @johnbarnes4]

All of my knurling problems to date have been with straight knurls. I have now fitted diamond knurls and so far so good. I feel much more confident now. I will let you know how I get on with the parts I plan on making over the weekend. Thanks for the help guys. Great forum. John.

[john barnes 4Participant @johnbarnes4]

Knurled a few small parts over the weekend. Used narrow diamond knurls instead of the wider straight knurls I had used before. Much less pressure needed with these knurls. Still need a bit more practice but they turned out okay. Pictures in my album show the knurling tool and a close up of the knurling. the bluing on the knurl is because I welded threaded rod instead of screw cutting.

John

[John ReeseParticipant @johnreese12848]

I have been knurling since 1957. I have never been concerned with matching part diameter to the pitch of the knurl. With a knurling tool with a pivoting head I never have a problem with tracking properly. If the knurls don't track right off I just increase the pressure. The knurling tools built into the QCTP toolholder can be a problem. It is difficult to get both knurls to bear on the work evenly.

[john barnes 4Participant @johnbarnes4]

Hi John,

I was one year old when you started knurling. I was taught to knurl as a turning apprentice when I was fifteen but I have done hardly any knurling since and it has been like starting again from scratch. The new knurling tool I made and the narrower knurls I used seem to have made a big difference. Also it seems to me that diamond knurls are easier to get right than straight ones. Others on this forum agree with what you say about diameter not being critical and that is what I found also. My knurling tool fits in place of the toolpost and was made to be on centre. When squared the wheels bear very evenly on the workpiece. If you click on my photos you will see the knurling tool and an example of the knurling. I would be interested to know what you think.

John.

[John ReeseParticipant @johnreese12848]

John B,

It is a nice looking tool. The knurling on the screws is beautiful. I have been wanting to try aa clamp type knurling tool and will probably base it on your design.

John R.

[john barnes 4Participant @johnbarnes4]

I am sure you will like It if you make one. They are much kinder on the lathe than a push type.

John.

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