"What's the difference between a sewing machine…

A NSFW jogging riddle is:

Q: What’s the difference between a sewing machine and a female jogger?
A: A sewing machine only has one bobbin.

The pun is one the word “bobbin” (a spindle); a female jogger has two “bobbing.” The joke has been cited in print since at least the 1940s.

Google Books
Washington State Dental Journal
Volumes 9-10
1942
Pg. 24:
You know the difference be tween a sewing machine and a sweater girl is that the s.m. has one bobbin.
B. A. SUTTON

Google Books
The Iowa Engineer
Iowa State College
Volumes 48-49
1947
Pg. 36:
Freshman; “What is the difference between a sewing machine and a girl running for a trolley.”
Senior: “A sewing machine has only one bobbin.”

Google Books
Producers Monthly
Bradford District Pennsylvania Oil Producers Association
Volume 17
1952
Pg. 44:
What is the difference between a girl running down the street and a sewing machine?
Answer: A sewing machine only has one bobbin

Google Books
Typo Graphic
1953
Pg. 27:
What is the difference between a girl running down the street and a sewing machine?
Answer: A sewing machine only has one bobbin.

22 March 1974, San Francisco (CA) Chronicle, Herb Caen column, pg. 25, col. 1:
Giggling girl, describing herself as “O’Hair Bunny,” on the phone yesterday morn: “Hey, you know the difference between a sewing machine and a female streaker? A sewing machine has only one bobbin,” with which she disappeared in gales of laughter.

Google Books
Dirty Stories for All Occasions
By Andrew L. Cleveland
New York, NY: Galahad Books
1980
Pg. 36:
What’s the difference between a sweater girl and a sewing machine?
A sewing machine has only one bobbin.

Google Books
1001 Great Sports Jokes
By Jeff Rovin
New York, NY: Penguin Books
1991
Pg. 198:
Q: What’s the difference between a woman jogging and a sewing machine?
A: A sewing machine has just one bobbin.

Google Groups: talk.bizarre
pro and con
Gerald Oskoboiny
9/23/92
(...)
q. What’s the difference between gypsy’s sewing machine and a woman jogging?
a. The sewing machine only has one bobbin.

Google Groups: rec.humor
Female Joggers
Myron Selwyn Lodkin III
6/24/94
Q.- What’s the difference between a female jogger and a sewing machine?
A.- A sewing machine only has one bobbin.

Twitter
Ghetto Smurf
@BimblerBaz
RT @Radeeboi: What is the difference between a sewing machine and a lady horse rider? < A sewing machine has only got one bobbin

6:08 PM - 9 Sep 2009

Twitter
Melissa Attree
@MelAttree
#FridayFunny: What’s the difference between a woman running down the street and a sewing machine? A sewing machine only has one bobbin.
9:59 AM - 18 Sep 2009

Google Books
Jokes for Blokes:
The Ultimate Book of Jokes not Suitable for Mixed Company
By Llewellyn Dowd and Phil McCracken
London, UK: Ebury Press
2011
Pg. 93:
What’s the difference between a sewing machine and a girl jogging?
A sewing machine only has one bobbin.

Twitter
Shit Jokes
@ShitJokes
What’s the difference between a sewing machine and a big boobed lady jogging?
A sewing machine only has one bobbin.
4:18 PM - 30 Sep 2017

Reddit—Jokes
Posted by u/bbcuh162 July 9, 2019
What’s the difference between a sewing machine and a female jogger?
A sewing machine only has one bobbin.

“What’s the difference between a sewing machine and a female jogger?” (joke)