Knurling wheels misterry

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?

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

That sounds like a bin job!

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

Tony

Does it matter? What does the pattern look like?

Rod

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

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

Phil

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?

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

Brian G

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I’m with you there, Bernard

MichaelG.

… eagerly awaiting someone’s explanation..

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

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.

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

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!

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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.

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

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

Thanks for the clarification

I remain bewildered as to how that arrangement could be useful

… but we’re all here to learn.

MichaelG.

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

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