extra-fine knurling

[JasonBModerator @jasonb]

Or in more recent times rope knurling has come up several times on THIS forum, best link of the bunch looks like this one

[Michael GilliganParticipant @michaelgilligan61133]

Thanks, Neil

That's very helpful … especially as it supports my assumption that diamond-pattern knurling would be most uncommon on pre-20th Century scientific instruments.

MichaelG.

[JasonBModerator @jasonb]

Not Done It Yet

Any chance of enlightenment on how your fine screwcutting running up and down would work yet?

If I were to run a fine R/H thread up a piece and then a L/H thread down the same piece is all I would end up with is this, which does not look much like any form of knurl

If you show me your method, then I'll show you mine that can give diamond patterns like this

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 29/09/2016 13:12:31:

Thanks, Neil

That's very helpful … especially as it supports my assumption that diamond-pattern knurling would be most uncommon on pre-20th Century scientific instruments.

MichaelG.

I'm not entirely convinced it does if 'checkpattern' was the 'common' knurl in 1899, that suggests it must have been around for some time.

[SteveWParticipant @stevew54046]

LH/RH thread would need to be multi start threads to get the helix angles large enough to provide a pattern(?). I think it might work.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 29/09/2016 15:10:03:

Posted by Michael Gilligan on 29/09/2016 13:12:31:

Thanks, Neil

That's very helpful … especially as it supports my assumption that diamond-pattern knurling would be most uncommon on pre-20th Century scientific instruments.

MichaelG.

I'm not entirely convinced it does if 'checkpattern' was the 'common' knurl in 1899, that suggests it must have been around for some time.

.

I suspect that 'checkpattern' may be a reference to Ornamental Turning work … But obviously can't be sure.

Hence my interest in finding the date of 'First Use' of knurling to that pattern on screw heads, and such.

MichaelG.

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 29/09/2016 19:35:59:

Posted by Neil Wyatt on 29/09/2016 15:10:03:

Posted by Michael Gilligan on 29/09/2016 13:12:31:

Thanks, Neil

That's very helpful … especially as it supports my assumption that diamond-pattern knurling would be most uncommon on pre-20th Century scientific instruments.

MichaelG.

I'm not entirely convinced it does if 'checkpattern' was the 'common' knurl in 1899, that suggests it must have been around for some time.

.

I suspect that 'checkpattern' may be a reference to Ornamental Turning work … But obviously can't be sure.

Hence my interest in finding the date of 'First Use' of knurling to that pattern on screw heads, and such.

MichaelG.

 

As far as '(k)nurling' + 'checkpattern' seems to be a Googlewhack, but 'check pattern' seems to be a pretty common description of a double-diagonal knurl.

Neil

Edited By Neil Wyatt on 29/09/2016 19:52:20

[Maurice Cox 1Participant @mauricecox1]

With reference to rope edge knurling, in 2012 I rebuilt a very old Stuart No. 1. At some point in its life, it had been fitted with a shaft governor. The two "knobs"| which adjust and lock the return spring tension are rope edge knurled, first picture, and I wanted to replicate this on a rod length adjuster, a stop valve hand wheel, and a near copy of a Stuart lubricator. I succeeded fairly well using the knurling tool shown. It has a convex face. I mounted it at 45 degrees in a boring tool holder. Having prepared the blank wheel, I engaged back gear and presented the knurl to the work. Once it had been round a couple of times, I moved the tool sideways to the right. You could hear the load come off the gears, and as this happened I fed the tool in to restore the sound. I progressed sideways until I thought it had cut far enough down the side. I then moved the tool the other way, retracting the tool as I went. On reaching the centre again, I continued to the left , feeding it in again while listening to the sound. Doing it all in one go without stopping, sounds like juggling, but I was surprised how quickly I got the feel of it. If prefered you can stop having gone one way, then retract the toll, return to the centre of the work, and carefully reengage the knurl to do the other side. The results are in the pictures. On the rod length adjuster, only the adjust screw is rope edged, the small locking screws are straight using the same knurling wheel. Not my best efforts at photography, sorry. I don't know how far down the sides the knurling came on old equipment, but I was able to duplicate that which was on the engine already. I hope this may be of some help

Maurice Cox

[Michael GilliganParticipant @michaelgilligan61133]

Of course, CheckPattern is also used on gunstocks … Cut by hand.

I'm still not sure, but the reference may just be to an effect rather than to 'prior art' in knurling.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Nice work, Maurice

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Here's another interesting patent [637,320] from 1899 **LINK**

MichaelG.

[duncan webster 1Participant @duncanwebster1]

All this got me thinking. as the purpose of knurling is to increase the friction when turning whatever has been knurled, surely a straight knurl is what you want? Normal to the circumferential force. Why do we use diamond? Is it easier to create?

Edited By duncan webster on 30/09/2016 00:47:46

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 29/09/2016 20:53:12:

Of course, CheckPattern is also used on gunstocks … Cut by hand.

I'm still not sure, but the reference may just be to an effect rather than to 'prior art' in knurling.

MichaelG.

I don't want to flog a dead horse but 'as indicated on nut e' makes it quite clear he is referring to a diamond knurl on an adjuster.

I would like to take credit for finding teh first example of a diamond knurl, but I suspect not.

Neil

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 29/09/2016 22:13:38:

Here's another interesting patent [637,320] from 1899 **LINK**

MichaelG.

That's my just reward for searching up to 31 August 1999 instead of 31 December

Neil

[Neil WyattModerator @neilwyatt]

Posted by duncan webster on 30/09/2016 00:47:28:

All this got me thinking. as the purpose of knurling is to increase the friction when turning whatever has been knurled, surely a straight knurl is what you want? Normal to the circumferential force. Why do we use diamond? Is it easier to create?

Edited By duncan webster on 30/09/2016 00:47:46

It's more decorative and appears 'sharper' perhaps?

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 30/09/2016 07:17:40:

I don't want to flog a dead horse but 'as indicated on nut e' makes it quite clear he is referring to a diamond knurl on an adjuster.

I would like to take credit for finding teh first example of a diamond knurl, but I suspect not.

Neil

.

Noted, and agreed, Neil

I had a rather wearying day, yesterday and wasn't really on form

MichaelG.

[JasonBModerator @jasonb]

Well as Not Done It Yet has not got back to us yet I'll enlighten you as to how the screwcutting method may work in theory.

Any fine pitch thread won't be any good as you will get a very long groove pattern that runs around the rod not across it so only good for pulling not turning.

If you up the pitch then you start to get something more like an oil groove, pitch is 1D

As I mentioned earlier and Steve also mentioned to get something like a knurl then a multi start thread is needed, this is the same pattern as above but with a 24 start

Still the diamonds are a bit long so playing about with teh figures to get the optimum diamond pattern the pitch of the "screw" needs to be Pi x D and the number of starts sufficient to make sure one Vee runs into the next and does not leave any flat tops to the diamonds (had to shorten the sample as it was taking the CAD a long time to do the cutting)

If you want to look at this finished knurl in more detail there is a 3D pdf here that allows the part to be moved about, zoomed into etc

The only problem with this is that unless you are trying to cut knurl a 1mm dia rod most lathes can't easily cut PiD pitches, the example above was 50mm dia so needed a 157mm pitch or about 0.17tpi. So the only real options for a screwcut method would be an electronic leadscrew, 4-axis CNC or as Michael hinted at above it could be done on an ornamental lathe.

J

 

Edited By JasonB on 30/09/2016 08:11:26

[not done it yetParticipant @notdoneityet]

I'm not likely too, eiter. I made a suggestion. Im not an engineer. Others have added that it should work, but with a small pitch(?) multi-start thread setting. Go figure for yourselves. Snarky comments from (a) poster(s), who think he/they are above the rest, can sort it out between himself/themselves.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by duncan webster on 30/09/2016 00:47:28:

All this got me thinking. as the purpose of knurling is to increase the friction when turning whatever has been knurled, surely a straight knurl is what you want? Normal to the circumferential force. Why do we use diamond? Is it easier to create?

.

Excellent logic, Duncan

The cap on my toothpaste tube is slightly tapered; a suitable diameter; and quite strongly 'knurled' … Ergonomically designed for its purpose.

One ergonomic subtlety is to use different styles and 'strengths' of knurl for different controls on an instrument: This allows them to be interpreted by touch, and, done well, that can be helpful.

Picking-up on yor closing remark: I think the diamond knurl might involve less 'shifting of metal' to produce a given visual and tactile effect [still pondering that one]; and may therefore be more efficient, production-wise.

MichaelG.

[JasonBModerator @jasonb]

Posted by not done it yet on 30/09/2016 08:21:10:

I'm not likely too, eiter. I made a suggestion. Im not an engineer. Others have added that it should work, but with a small pitch(?) multi-start thread setting. Go figure for yourselves. Snarky comments from (a) poster(s), who think he/they are above the rest, can sort it out between himself/themselves.

I read it as a question as it had ? at the end. But if it was a statement other members asked how that would work and I provided an answer to both as you did not come back with anything.

Also can't see anyone else suggesting a fine pitch, as I said above steve also mentioned multistart and I had mentioned it previously. Pitch is related to diameter but how fine the knurl is will be a combination of depth of cut and number of starts, as depth gets less number of starts has to increase.

Jason, not an engineer either.

Edited By JasonB on 30/09/2016 08:39:56

[Dave MartinParticipant @davemartin29320]

Posted by duncan webster on 30/09/2016 00:47:28:

All this got me thinking. as the purpose of knurling is to increase the friction when turning whatever has been knurled, surely a straight knurl is what you want? Normal to the circumferential force. Why do we use diamond? Is it easier to create?

Two reasons I can think of – firstly, as Duncan suggests, it may be for production reasons / more forgiving of slight misalignment. The second is that if it is the head of something that needs to be pulled, diamond gives grip when applying axial force.

[NJHParticipant @njh]

…." Jason, not an engineer either."

Oh yes you are:-

ENGINEER : A person who designs, builds, or maintains engines, machines, or structures.

Norman

( and, although I have engineering qualifications and worked as an engineer ( not mechanical I grant you)  you are a better engineer than me!)

Edited By NJH on 30/09/2016 12:12:49

[JasonBModerator @jasonb]

Oh no I'm not.

What I meant was that apart from school metal work I have no engineering training or background and have never worked in the engineering profession.

Now if there was a definition of Model or Hobby Engineer as a person who designs models, builds models and maintains models all with no training or relevent qualificationsthen that cap may fit

[NJHParticipant @njh]

Well Jason by the dictionary definition I posted what you do makes you ( and I guess the rest of us ) an engineer.

That you do this as a hobby with no formal training or experience makes you a very fine engineer in my book. That you are also prepared to give others on this forum the benefit of your experience is splendid. Don't be modest man – accept the praise!

[Ian S CParticipant @iansc]

Model engineers are often trained in the university of life, supervised by them selves, gaining instruction from books that are maybe 80 years old, and more. That was the time when industry closer matched a good bit of what we do. My first book on arc welding is dated 1942.

Ian S C

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