Knurling wheels misterry

[Sonic EscapeParticipant @sonicescape38234]

I bought one of these knurling tools that seems to be everywhere. They came with three sets of wheels. When I merged together the wheels with the largest teeth I noticed that they only partially overlap. Then I counted them and one wheel has 33 teeth and the other 34! Is this normal? What can be the purpose?

[Sonic EscapeParticipant @sonicescape38234]

[MacolmParticipant @macolm]

Possibly a "hunting tooth" to average out variations, so avoiding patterning?

[bernard towersParticipant @bernardtowers37738]

That sounds like a bin job!

[Tony Pratt 1Participant @tonypratt1]

China (or India), strikes again, get a refund.

Tony

[Roderick JenkinsParticipant @roderickjenkins93242]

Does it matter? What does the pattern look like?

Rod

[BazParticipant @baz89810]

Posted by Sonic Escape on 05/04/2023 21:17:51:

I bought one of these knurling tools that seems to be everywhere. They came with three sets of wheels. When I merged together the wheels with the largest teeth I noticed that they only partially overlap. Then I counted them and one wheel has 33 teeth and the other 34! Is this normal? What can be the purpose?

No it is not normal, wheels should have the same number of teeth or serrations.

[Phil WhitleyParticipant @philwhitley94135]

Try it, It may be perfectly good, it does sound like a hunting tooth, try it out and post up some pics.

Phil

[bernard towersParticipant @bernardtowers37738]

I don't understand how you can have a hunting tooth on a knurling tool when the object is to have the wheels follow the same path every revolution or am I missing something?

[Brian GParticipant @briang]

First question that comes to mind is whether the diameters are in the same 33/34 ratio?

Brian G

[Michael GilliganParticipant @michaelgilligan61133]

Posted by bernard towers on 06/04/2023 19:17:15:

I don't understand how you can have a hunting tooth on a knurling tool when the object is to have the wheels follow the same path every revolution or am I missing something?

.

I’m with you there, Bernard

MichaelG.

… eagerly awaiting someone’s explanation..

[SillyOldDufferModerator @sillyoldduffer]

Odd, but are the two wheels the same diameter? If so, they should have the same number of teeth to give the same pitch.

A possible explanation. Noting that it's the pitch that's important, not the number of teeth, if one of the wheels is made slightly larger, an extra tooth could be added to maintain the same pitch. The advantage of having an extra tooth on one wheel is it would distribute wear by rolling one wheel slower than the other.

Dave

[FulmenParticipant @fulmen]

I don't buy the hunting tooth theory, the two wheels aren't connected in any way.

My guess would be that they got two batches of cheap wheels and just mixed them together. If they're the same pitch the knurl should turn out the same. If they're the same diameter the knurl would be slightly asymmetric but I doubt it's noticeable.

[DiogenesIIParticipant @diogenesii]

33/34.. ?..for creating metric knurls on Imperial stock..?

[MacolmParticipant @macolm]

Once there is an impression of the knurl on the work, it becomes exactly like three gear wheels running together. They stay in mesh. The advantage of a hunting tooth is that the effects of irregularities and wear will be averaged. The wheels would, of course, be constant pitch so slightly different diameters. If so, this may be a superior knurling tool!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Macolm on 06/04/2023 22:18:01:

Once there is an impression of the knurl on the work, it becomes exactly like three gear wheels running together. They stay in mesh. The advantage of a hunting tooth is that the effects of irregularities and wear will be averaged. The wheels would, of course, be constant pitch so slightly different diameters. If so, this may be a superior knurling tool!

.

I’m happy to be wrong, but this statement from the opening post suggests wheels of the same diameter, but with different tooth counts: “When I merged together the wheels with the largest teeth I noticed that they only partially overlap.”

MichaelG.

[Sonic EscapeParticipant @sonicescape38234]

The wheels have exactly the same diameter, 25.83mm. I can't try them very soon because I have to fix better the tool post for this kind of operation. Here there is a better picture where you can see how the teeth start to be misaligned from the bottom:

This is how I noticed in the first place that they have a different number of teeth. Besides that the wheels are identical

Edited By Sonic Escape on 07/04/2023 07:47:05

[Sonic EscapeParticipant @sonicescape38234]

For the 1mm pitch wheels is the same story. 69 and 70 teeth. So maybe there is a reason for this. Apparently knurling is still hiding some secrets

It is strange that they don't have a marking to separate them.

Edited By Sonic Escape on 07/04/2023 07:59:02

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the clarification

I remain bewildered as to how that arrangement could be useful

… but we’re all here to learn.

MichaelG.

[Martin KyteParticipant @martinkyte99762]

Why does it matter?

Each wheel has only to register in the imprint it made on the previous revolution. Even the rivet counters are never going to notice that the rhombus pattern is not perfectly dimensioned across the sides.

regards Martin

[John HaineParticipant @johnhaine32865]

Try rolling them across a softish flat surface while fitted in the tool. Soft wood, plasticine? See what kind of pattern they imprint.

[Michael GilliganParticipant @michaelgilligan61133]

You’re right, of course, Martin … which presumably kills the ‘hunting tooth’ proposition.

My own curiosity concerns around how that arrangement could be useful, rather than whether it’s good enough.

MichaelG.

[Sonic EscapeParticipant @sonicescape38234]

Posted by John Haine on 07/04/2023 08:35:15:

Try rolling them across a softish flat surface while fitted in the tool. Soft wood, plasticine? See what kind of pattern they imprint.

The pattern is ok

[Martin KyteParticipant @martinkyte99762]

I suspect the variation in pitch is down to the method of manufacture. If the knurls have bee made by knurling themselves then they could quite easily have a pitch error. If you look at the crests on the knurls they don’t suggest they were cut but formed which would raise the surface as metal was displaced.

regards Martin

PS This would make the pitch discrepancy an artefact of the manufacturing process rather than any intentional or useful design.

Edited By Martin Kyte on 07/04/2023 09:57:50

Edited By Martin Kyte on 07/04/2023 10:00:59

[Phil WhitleyParticipant @philwhitley94135]

As I suspected there is nothing wrong with them!

Phil

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