"Roy Smith" wrote in message
...
| Yesterday I was holding in my hand a grub screw. A rather ordinary
| object, costing no more than a few cents, but I realized I have no
| idea how they are made.
|
| The threads are no problem, but how do the get the allen-head
| indentation in the end?

I'll take another stab at it, having seen bits and pieces of the process
and similar operations over the years. Starting with a drawn roll of steel
wire, the wire end is heated (maybe, not so sure this is needed) and held in
a mandrel or clamp. At the same time a round punch forms the hole another
die shears off the other end. There is now a slug with the proper ends
(various shapes are available) which is dropped into a mill that rolls the
threads in between a couple plates. Finally a final cleanup punch with the
hex shape. You can barely see the material from the punch if you look in
the end.
When you look at the other end of non-specified grub screws (whatever
you call ones that have not been specified as having a certain point on
them) you'll see a little bit of material that has rolled over the end from
thread rolling. After the threads have been rolled then the final point or
cup gets put on it somehow or the other.

I used to be an industrial scale tech in another life and got to see how
sockets, wrenches, and other tools were forged/punched at one place (in
other words, buy the cheapest American brand you can find!) watched threads
rolled in another shop that made bolts (the machines weren't near as big as
expected,) and discovered that how the consumer is silly enough to pay more
for a different color of carpet pad that was simply called "premium" (carpet
pad is recycled foam from couches, beds, industrial processes, and so forth,
and dyed to make you want to pay more.) Very enlightening. While I'm at
it, I learned that the lowest fat hamburger is simply beef that has had less
fat added during the blending process to get to the specified amount. And
unleaded gas actually costs less to make than leaded!