Knurling - The Mechanics Behind It

[uv8452]

Self-built gadgets gain in appearance and usability if they are equipped with knurled knobs. A knurled knob signals an old white man that he sees an interesting thing which needs some adjustment.
Knurled knobs are very practical as they save the fumbling with spanners or Allen keys. More often then not, you can replace hexnuts with a threaded knob, provided that the needed clamping force is not too high and knob diameter and grip are high enough.

Most of the knurler designs I have seen at HMT (well over 100) look like heavy duty pliers. This originates perhaps in multi-spindle automatic lathes where the knurling ‚plier’ must engage the turned piece from the side. This is not necessary in the paradise of bricolage. If you modify the plier to a kind of garotte, keeping the knurling wheels in the middle (principle that was used by our members ‚mark f’ and ‚ndnchf’), then the molding of the knurling profile is easier to adjust and the forces involved become much smaller.

[tonyfoale]

Self-built gadgets gain in appearance and usability if they are equipped with knurled knobs. A knurled knob signals an old white man that he sees an interesting thing which needs some adjustment.
Knurled knobs are very practical as they save the fumbling with spanners or Allen keys.

Your conversion at the end of your second paragraph on page 1 needs some adjustment.

[uv8452]

Tony, thank you very much for the hint.
A finger force of 70 Newton corresponds roughly to 7 kilograms. Double this even more roughly and you get 14 lbf. The exact value is 15.7 lbf. I could have checked it easily that the '300 lbf' were wrong. I'm sorry. The woman's finger force of 50 Newton corresponds to 11.2 lbf.
Ulrich

[tonyfoale]

Tony, thank you very much for the hint.
A finger force of 70 Newton corresponds roughly to 7 kilograms. Double this even more roughly and you get 14 lbf. The exact value is 15.7 lbf. I could have checked it easily that the '300 lbf' were wrong. I'm sorry. The woman's finger force of 50 Newton corresponds to 11.2 lbf.
Ulrich

My rough mental conversion Kg or Kgf to lb or lbf is double it and add 10%. So 7 x 2 = 14, 14 + 1.4 = 15.4

"70 Newton corresponds roughly to 7 kilograms." No it doesn't, apples and oranges. 70 N corresponds roughly to 7 Kgf.

[mklotz]

My rough mental conversion Kg or Kgf to lb or lbf is double it and add 10%. So 7 x 2 = 14, 14 + 1.4 = 15.4
...

Yes, mentally multiplying by x.x is easy. Multiply by x, shift the decimal and add.

A meter is very close to 3.3 feet. One meter is 39.37... inches, which is 3.280833 feet or about 3.3 feet

10 meters = 32.808... feet

10 * 3.3 = 33 feet, about 0.6% error

[Toolmaker51]

To applications of and forces required, it seems straight knurls appear with items that react to fine adjustments, diamond knurls for coarse grip.

[mklotz]

Coarse knurls can be tough on the fingers for anything that needs frequent adjustment; a fluted knob is usually more comfortable, at least in my estimation.