The designer sat at his drafting board
A wealth of facts in his head was stored
Of what can be done with a radial drill
A turret lathe or a vertical mill
But above all things a knack he had
Of driving machinists completely mad
So he mused as he thoughtfully scratched his bean
Just how can I make this thing hard to machine
If I make this body perfectly straight
The job would surely come out first rate
But that would be easy to cut and pour
It never would make the machinist sore
So I'll throw in a compound angle there
And a couple of tapers to make them swear
Now brass would do for this little gear
But that's too easy to carve I fear
So just to make a machinist squeal
I'll have him machine it from tungsten steel
And I'll put the holes that hold the cap
Down underneath where they can't be tapped
Now if they can make it they'll do it by luck
‘Cause it can't be held with a dog or a chuck
And it can't be drilled nor planed nor ground
So I think my design is completely sound
The designer sat back. His plan he surveyed
The screwiest thing he had ever made
He signed his name with a line so thin
Then put down his pencil and started to grin
He shouted with glee, “Success at last
I've designed a part that can't even be cast.”