Are these two things related? Sure seem to me that they would be.

Yes, they are. Yiddish shtik 'bit, piece' (also spelled schtick and shtick) is cognate with German stück same meaning. Though, in German, a stick is called Stock. They all come with a host of other cognates from PIE *steigh- 'stick'.

In looking these 2 words up to see how their definitions relate, I found that "slapstick" has a meaning that I hadn't known. It is a device used by actors to make a loud noise when someone strikes another, without causing injury. I hadn't known that!

And of course, Kalleh, the Three Stooges' favorite routines were slap-shtik!

It is a device used by actors to make a loud noise when someone strikes another, without causing injury.

I'd've thought that the meaning of slapstick was pretty well know, and so I did not really go into it. The stick in slapstick is uncontroversial semanticswise.

I think "slapstick" is pretty well known; I just hadn't heard of that acoustic device, though it makes perfect sense. However, "slapstick" comedy of course is used all the time.

Now, one thing I haven't ever seen before is "I'd've." I like it!

Quoting:
CW: Are these two things ['slap stick' and 'schtick'] related?
jheem: Yes, they are. Yiddish shtik 'bit, piece' (also spelled schtick and shtick) is cognate with German stück same meaning. Though, in German, a stick is called Stock.

The authorities say that the word stork, the bird, comes from this same root -- but why? Some say that the allusion is "perhaps with reference to the bird's stiff or rigid posture," others speculate that it is "probably from the stiff movements of the bird".

With all due respect I suggest that there is a much more obvious and earthy reason why a bird long associated with bringing babies might, just might, be associated with and named the words for 'stick' and 'stiff'.

Perhaps the stork's stick-like legs also have a bearing on the matter?

Also, the stork's nest is made of sticks. Actually though the authorities say that stork is from a different root: *ster- 'stiff'. While stick and shtik come from *steigh- (which see above).

Kalleh, I meant that I thought everybody knew what a slapstick was, i.e., the device from which the comedy genre got its name.

So - does all this relate to the saying

"More fun than you can shake a stick at"?

"Slap", in UK slang at least, also means make-up. It originated with stage make-up according to this site. Might a "slap-stick" therefore be lipstick or similar cosmetic?

Great site, Arnie! I found the nearby entries to slap interesting, too. The things you learn around here!