Key h9 or k9

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1

Hello

I have a silly question about the keys:

Why on the width of the keys we find (often) 2 possible tolerances h9 or k9?

For manufacturing reasons? historical?

Thank you

2

See these links

http://www.tracepartsonline.net/PartsDefs/Production/EMILE_MAURIN/10-06082008-153109/documents/barreau-clavette-acier-31-995-pdf-65-ko-31_99-LMOD1.pdf

http://www.mitcalc.com/doc/tolerances/help/fr/tolerancestxt.htm

http://www.langlet.fr/bdd/docs/4-tolerances-systeme-iso-tolerances-ajustements.pdf

tolerance h 9 

tolerance k 9 

@+ ;-))

3

Thank you for the links (even if I know what an adjustment is), my question was more about why steel keys are in k9 tolerance and stainless steel in h9 (see Emile Maurin link)

Ease of manufacture of the key?

To differentiate stainless steel keys from steels?

1 Like
4

Hello;

The choice of tolerance is based on  the operation of the system as well as the overall material (resistence, bending,.....)

5

Hello;

The choice of tolerance is based on  the operation of the system as well as the overall material (resistence, bending,.....)

6

Hello

The DIN 6885 (all shapes) or NFE 22177 standard specifies that the tolerance for a new assembly must be h9 on the width, and h9 or h11 on the height, whether the material is stainless steel or steel. So negative tolerances.

The k9 and zb10 tolerances, which are also found on the market, are positive tolerances that allow adjustment at the time of assembly for mated-up shafts. This makes it possible to save a damaged tree, or to adjust a housing to the wrong tolerance.

Distributors therefore offer tolerances according to their supplier's offer. There are 2 manufacturers of keys in France, the distributors mentioned above use one or the other.

See attached file.

 

I hope this will help you.

Stéphane Server, Gardette

 

 


argumentaire_zb10_gardette.pdf
3 Likes
7

Thank you very much @Sales & Development Gardette Group for the answer (and for understanding my question).