Knurling wheels misterry

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Phil Whitley on 07/04/2023 10:20:08:

As I suspected there is nothing wrong with them!

Phil

.

Is the wink there because you have now conveniently omitted to mention that you also espoused the ‘hunting tooth’ theory ?

MichaelG.

[Chuck TaperParticipant @chucktaper]

"If the knurls have bee made by knurling themselves then they could quite easily have a pitch error."

Resulting in the same 1 tooth difference? Is that likely? (granted from a sample to 2!!)

On the other hand – looking at the impression – is it drifting slightly to the left/right.

Why? How?

Probably nothing.

Regards

FC

[Martin KyteParticipant @martinkyte99762]

Posted by Chuck Taper on 07/04/2023 10:32:32:

"If the knurls have bee made by knurling themselves then they could quite easily have a pitch error."

Resulting in the same 1 tooth difference? Is that likely? (granted from a sample to 2!!)

On the other hand – looking at the impression – is it drifting slightly to the left/right.

Why? How?

Probably nothing.

Regards

FC

Well the master doing the forming does not have to be the same diameter as the knurl it is making. In fact it it’s advantageous to be so as it would take longer for it to wear. This would make the number of ‘teeth’ around the wheel subject to some variation as it self registered. Similarly the same effect could occur if they were made by a diagonal free hobbing process. That opens a couple of possibilities for a start.

Really all I am saying is unless we know for definite how the knurls were made much of this is speculative including any suggestion that it was intentional because of some operational advantage in use.

regards Martin

[MacolmParticipant @macolm]

Now we have most of the facts, it seems that it simply does not matter the exact number of teeth round a given diameter. Once a clean single (not double!) impression on the work has been started, a successful knurl will be formed by going to the full depth. An interesting parallel is car gearboxes. Say for a given gear 30:20 teeth would not be quite ideal, instead 29 teeth are cut on a 30 size blank, so a 29:20 ratio pair is formed. This is very a common technique, and does not seem to cause any problems.

The last bit of info that would be of interest is if the OP will make a sample knurl, and count the number of clock and anticlock teeth.

[Sonic EscapeParticipant @sonicescape38234]

But if the diamond pattern is oscillating left-right then it will ruin work. Unless the circumference of the work coincide with the period of this oscillation. Or a multiple of it. Here is a longer sample of this knurling wheels. I'm afraid these wheels are useless.

Edited By Sonic Escape on 07/04/2023 13:29:01

Edited By Sonic Escape on 07/04/2023 13:30:51

[old AlParticipant @oldal]

The real question is , does it give a suitable knurl. And if not have you tries setting the tool on ctr height, a bit below and a bit above and then upside down to all of the above.

I dont use science in what i use unless it dosnt work. Life is too short

[Chuck TaperParticipant @chucktaper]

Posted by Sonic Escape on 07/04/2023 13:28:22:

But if the diamond pattern is oscillating left-right then it will ruin work. Unless the circumference of the work coincide with the period of this oscillation. Or a multiple of it. Here is a longer sample of this knurling wheels. I'm afraid these wheels are useless.

True but if the tool were allowed to freely move along the work at the rate of drift (imaged above) above then a perfect knurl would result. (?)

A diagonal knurling wheel is in effect a multi start thread. Another wheel with one extra tooth sets up a differential screw type system. That would underlie the drift. (insert hard math here!)

I found this link – http://www.reed-machinery.com/wp-content/uploads/2019/04/knurls-and-knurling-tech-data-master.pdf

Which is more than I can onboard in the middle of the day.

Regards.

Frank C.

[Martin KyteParticipant @martinkyte99762]

As per usual some people are overthinking this. Knurling works because the knurl is free to follow the pattern of ridges it has just made and generally will do so. Just occasionally it can be half a ridge out and you get a double row. The trick is to be a little aggressive and make your first impressions deep. Each knurl acts independently so don’t think diamonds think diagonal grooves.

I would not have even noticed the pitch difference. So long as the tool worked that would be it and if it didn’t it would have probably been slung in a drawer and forgotten about.

regards Martin

[Neil WyattModerator @neilwyatt]

If the wheel has two pitches, it can't slip to lock in with both of them, it either goes sideways or produces a bastard knurl.

Neil

[Martin KyteParticipant @martinkyte99762]

Posted by Neil Wyatt on 07/04/2023 17:19:14:

If the wheel has two pitches, it can't slip to lock in with both of them, it either goes sideways or produces a bastard knurl.

Neil

But it doesn’t have two pitches it’s two independent wheels each forming their own series of ridges.

regards Martin

[Neil WyattModerator @neilwyatt]

Posted by Martin Kyte on 07/04/2023 17:57:00:

Posted by Neil Wyatt on 07/04/2023 17:19:14:

If the wheel has two pitches, it can't slip to lock in with both of them, it either goes sideways or produces a bastard knurl.

Neil

But it doesn’t have two pitches it’s two independent wheels each forming their own series of ridges.

regards Martin

Of course! Excuse my brain f*rt!

N.

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