there are several ideas out there about the origin of the term “eight-six”
If anyone can get to the bottom and deliver the truth, it’s the SDMB.
Somehow, I’d connected it with 86 fathoms and Davy Jones’ locker. Eh, live and learn.
Just so you know, Cecil already covered this:
www.straightdope.com/classics/a1_291b.html
It talks about how 86 was a term in the 1920’s in diners, to mean all out of something. Read for yourself.
There has been at least one follow-up thread discussing Cecil’s answer. http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=130341&highlight=where+term
Cecil’s answer is still correct.
The earliest use of the term found so far was by Barry Popik. It appeared in a Walter Winchell column from 1933 and was offered by a “soda-jerker” as meaning “all out of it.”
Cecil’s column basically says he doesn’t know the answer. I have heard that it comes from grave dimensions: 8’ long casket, 6’ deep.
The average length of a casket is 84 inches, not 96" or 8’; width 28 inches, and height 23 inches. I got this off of two different websites. Hope this helps in the process of elimination at least.
Wrong. What Cecil said is
Considering that there are ample print cites from the 1930’s backing him up, he got it right.
Having worked in many bars and restaraunts, I knew that it was in use there still, figured it originated there as well. I tend to agree with danielle801 in that Cecil’s column basically says he doesnt know the answer.
“Derives from a roundabout code…” doesn’t exactly give the origins. The use of the term by line cooks alerting waitstaff that the particular item just ordered is no more resulting in its popularization I buy completely, but it doesn’t exactly explain the origin. As close as the “Master” comes is to suggest probably because it rhymes with “nix”.
That’s hardly definitive.
Origin and birthday are two different things. Otherwise, it’s just a tautology.
Sheesh! And I though that I was pedantic. 
To the OP. No one has yet figured out the “origin” of the term “86.” For that matter, probably 99% of all the slang terms and phrases in the English language are of “unknown origin.” Etymologists and linguists may search in vain, but the true origin will usually elude them. The best that they can FUCKING DO is try to find print cites and then try to figure out just why the first person in the world who ever used the term, used the term the way they did. To Cecil’s credit, he did by offering “nix” as noted by pfbob. I personally don’t think it is correct, but that’s just my opinion.
daniel801. You’ve “heard” that it comes from the dimensions of a grave. Where did you hear that? When? Do you think the source had any specialized knowledge of the origin of the phrase? Why? Any suggestions on how the grave origin might have gotten picked up by diner and soda fountain employees in the 1920-30’s?
IN the same Walter Winchell column, there were offered other terms that were used by the soda jerk----“81” was a glass of water, “13” meant that a “big boss” was around, “89” meant that a big movie star was in the joint. So it was possibly just a part of a fad at the time. Maybe nothing more than that.
I didn’t mean it to read that way. My point is that finding the first usage doesn’t really explain why that term was introduced. Why did they pick 86 instead of widget or 4.6, was my angle. Mentioning that I had heard it as grave dimensions lends insight into why “86” may have been used. I’ll go with the “rhymes with nix” idea for now (of course 6 works as well, so there’s gotta be more to it.)