Displaying Minimum Fillet Weld Size 5

[LobstaEata]

Hi all

There has been a debate in the office regarding if it was ever appropriate to show a fillet weld call on a plan without the size. Some engineers "in the day" were taught that displaying a fillet weld symbol without including the weld size used to indicate that a minimum weld should be assumed by the fabricator. Currently, fillet weld sizes are routinely displayed, on one (or both) side of the arrow line, depending on whether the weld is a single or double fillet.

The AISC Steel Construction Manual, since at least 1989, has displayed the same Standard location of weld symbol elements (currently Table 8-2 in AISC 360). A passage from this table reads that "Arrow and Other Side weld sizes are of the same size unless otherwise shown", suggesting that the weld size need only be displayed on one side of the line (for a double fillet) in most cases. Dimensions (length/spacing) however must be shown on both sides of the line. Nowhere however, does the code mention that the size may be left off the call, if a fillet weld is to be a minimum weld.

My question is this. Despite what seemed to have been industry practice in years gone (1980's) to omit the weld size for a minimum fillet call, was there ever any basis in code that would have allowed that practice to evolve?

Thanks for your assistance.

 

[Duwe6]

Correct in all regards. However, if you are feeling perverse, you can define an undimensioned fillet symbol as "minimum weld" in the General Notes portion of each drawing, along with a chart of minimum sizes versus basematal thicknesses.

And thus guarantee many holdups due to the welders doing the work asking somebody "Just what size do they want this weld?"

Not dimensioning a fillet was laziness by the draftsman in the 1960's, and still is. Or possibly ignorance, being perpetuated across many pages of prints. The decent thing to do is educate your draftsman/engineer and to put the size* on every symbol.
*Fillet sizes on prints are always the minimum acceptable size. And a good welder/fabricator will add a little for insurance from zealous Inspectors; i.e. 1/4" on dwg, welded at a shy 5/16". They have found out [the hard way] that when you aim at a minimum value, about half the time you will be below that value. ASME allows no underage, AWS only allows 10% of the length to be slightly undersize.

 

[gtaw]

I think is time for AISC to catch up with AWS A2.4 welding symbols. The weld size is suppose to be shown independent of the other since 1976.

Best regards - Al

 

[wannabeSE]

gtaw, AISC is getting closer.

13th edition Table 8-2: "Arrow and other side welds are the same size unless otherwise shown. Dimensions of fillet welds must be shown on both the arrow side and other side symbol"

14th edition Table 8-2: "Dimensions of fillet welds must be shown on both the arrow side and other side symbol"

 

[3DDave]

What about welders who really pile it on? 1/8th weld called for and you get 3/8 to 1/2 inch? Is there a standard way of reining them in short of requiring grind/machine to size post weld? Not to mention the distortion from such excess.

Saw a bracket that had plenty of designed room for a fastener; welds on .06 metal are tangent to the mounting holes starting from a wall a .38 to .50 away.

 

[gtaw]

It is called training and disciplining your work force.

Best regards - Al

 

[weldstan]

gtaw,

Wonderful answer!