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STK 4

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Mick72

Mick72

Mechanical
Jan 23, 2009
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I would like to know what STK stands for and when should it be used.

Thank you

Mickey
 
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I have seen it used to indicate "stock", as in from-the-mill condition. While I'm not sure if it should be used based on drafting standards, it is typically used to indicate sizes of materials that should not need to be modified. For example, if using a piece of angle iron with a 5" leg and 6" leg, a leg might be dimensioned as " 5" STK " to indicate which leg is which. With the "STK" notation, it is generally assumed that title block tolerances do not apply and it is basically a reference dimension in that sense.

-- MechEng2005
 
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Per ASME Y14.38z-2002 STK is an abbreviation for STOCK

ASME Y14.5M-1994 1.4 (a) "Each dimension shall have a tolerance, except for those dimensions specifically identifed as ... or stock (commercial stock size)..."

For a stock material the tolerances as defined in the relevant material spec apply. So it's not quite a reference dimension, more a 'soft' reference to the relevant material spec.



KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies: What is Engineering anyway: faq1088-1484
 
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We have used stock for a raw material surface that we would machine. So we sometimes (Very rare) Put a reference dimension from the machine surface to a phantom line of what the raw material was to indicate to the machinist how much material is being removed.
 
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Yep because I do not agree with this practice. This STk label was on some older prints that we have. It was a different example of stk being used than what was in Kenat's description. We do not practice this at all on our new prints. If we create a new print from one of the older prints we keep the STK on the print to make the prints consistent.
 
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STK should be used sparingly anyway, especially when dealing with plating which can vary in thickness by as much as the next lower and higher sizes. It is best to just let the machinist use the material configuration of their choosing (as long as the type is correct, of course). However, with sheet metal, I would say using STK is some what important, but only used in the way that KENAT did mention.

Matt Lorono
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I would agree that STK is stock. Although you need to be careful when assuming things. I used Ø.250S.F. for a spot face on a shaft. I had a vendor call up saying that they thought it was surface finish.
 
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Well, in fairness I don't think "S.F." is in the current industry standars for Spot Face. Althouth "SF" is in ASME Y14.38a-2002 (there are 3 other definitions for SF too) but Y14.5-94 uses the same symbol as a counterbore for the most part.

KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies: What is Engineering anyway: faq1088-1484
 
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Difference in a Spotface and a Counterbore, is usually depth. They can be produced in the same way, saometimes. but the spotface is depth limited to providing a flat surface of the specified diameter. They are usually used on castings to provide a smooth seat for a washer under a bolt or nut. Counterbores provide a depth into the part, usually so the bolt head or nut is recessed below the original surface.


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Spotface is now in the 2009 standard with it's own callout now. As a result of a lawsuit it was separated from counterbore.

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I have had to recently defend the use of "STOCK" or "STK on tooling parts where specified thicknesses are unmachined stock material thicknesses (IAW 1.4a). It states that the tolerances are per the material spec, and thus not to be inspected per drawing "block" tolerances.
This is because some of our people thought the word STOCK should be in parentheses, i.e. reference.

If material stock size is in a material parts list on the detail drawing, stock thickneses are covered there.
If not, then stock thicknesses dimensioned on face of drawing need to carry the word STOCK, or STK to cover the applicable tolerance.

Further discussion of this regarding form is in paragraph 2.7.1.3 (1994) or 2.7.2(2009) of Y14.5.

 
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Well done Ron, I was looking for that when I put my first reply.

asme Y14.5M-1994 said:
2.7.1.3 Form Control Does Not Apply (Exceptions to Rule # 1) The controls of geometric form prescribed by limits of size does not apply to the following:
(a) stock, such as bars, sheets, tubing, structural shapes, and other items produced to established industry or government standards that prescribe limits for straightness, flatness, and other geometric characteristics. Unless geometric tolerances are specified on the drawing of a part made from these items, standards for these items govern the surfaces that remain in the as-furnished condition on the finished part. …
Click to expand...


KENAT,

Have you reminded yourself of faq731-376 recently, or taken a look at posting policies: What is Engineering anyway: faq1088-1484
 
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