extra-fine knurling

Thanks for the clarification, Richard

Meanwhile, I'm struggling to find the 'introduction date' for diamond knurling

... I need access to whatever search engine they use on CSI.

MichaelG.

By no stretch of the imagination can this be considered definitive, but; on this page about [fabric] thread-counting microscopes, only [some] 20th Century examples have diamond-pattern knurling. **LINK**

http://www.microscope-antiques.com/threadcounters.html

Just to satisfy my curiosity: Can anyone find a 19th Century example of anything with diamond-pattern knurling?

MichaelG.

Do a Google Patent Search with an end date of 31 December 1899.

Scissors nurling tool patented in 1898, despite the drawing the text says the knurls are applied at diametrically opposite points allowing much smaller and longer work to be knurled.

Critcally its states "The common knurlwork being of a checkpattern, as indicated on the nut E, the face of the one knurl may be suitable for making the impressions on the work in the one direction, and the face of the otherknurl suitable for making the cross-impression, or the entire pattern may be put on the faces of both knurls, and of course any pattern may be placed on the knurls."

The earliest US patent to mention a knurl or nurl is Heysinger's 1878 pen-case patent, which appears to show a diamond knurl although the resolution is poor it is clearly not a straight knurl.

I propose that in future we should call the 'scissors knurl' a 'Miller-pattern nurling tool', acknowledging its inventor!

Neil

Quite a few years back(?1990s), there was an article in ME about making wheels for rope knurling by using a tap to hob the wheel in a bit of silver steel. Ian S C

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

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.

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

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.

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.

.

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

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

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.

Nice work, Maurice

MichaelG.

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

MichaelG.

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

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

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

Neil

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

Neil

.

Noted, and agreed, Neil

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

MichaelG.