I'm doing a set of exercises to make eye bolts and S hooks. I'm using
5/16" round M/S. I can make larger diameter rings OK, but I am
struggling with the smaller diameters. I am starting the bend on the
horn and attempting to finish it on the face. But the rings come out
oblong instead of round. Any suggestions on how to approach this are
P.S. I am using a Harbor Freight 110lb anvil. The horn is very
misshapen. Is making small rings impossible on this anvil? I don't
want to automatically give up because of the anvil, but don't want to
beat my head against the wall either.
The HF anvil's horn isn't misshapen. It's just different from a London pattern
anvil. The horn on a London pattern anvil has a circular cross section and
it tapers to a point. The horn on the HF anvil has a constant radius on the
top but tapers to a (rounded) point. You will notice that if you bend a bar
straight over the horn on a London pattern anvil it will veer to one side
because of the varying radius, while bending a bar straight over the horn of
your HF anvil it will bend straight.
Bending a ring smaller than that radius would be tough with that anvil.
I suggest you think about this until you completely understand what I just
wrote, and then decide what to do. You can certainly get a small cone and
true up your rings in one final step.
The need you have described is one reason why blacksmiths are always
looking at other peoples' junk piles. They are looking for pieces that
could be used for mandrels, etc. for some project they have in mind.
I have many anvils and only a couple have real pointy horns. So, it's
nice to have a separate tool for making small rings, etc. and the tool
might as well be up higher where you can easily see what's going on.
Make yourself an anvil bick (beak). Car or truck axle will work well.
If using car axle, the parent stock might be about 1 3/8" in diameter,
meaning that you will end up with a tool to make max diameter rings of
about 1 3/8"- 1 1/2" diameter. If truck axle, closer to 2".
In either case, take about 8 inches of stock. Butcher off an inch or
so and draw that out square to fit your hardy hole fairly closely (you
don't want to thing wobbling around a lot). Then draw a square taper on
the rest of it, all the way to a point. It'll get considerably longer;
that's fine. Now turn the taper into an octagon- a real GOOD octagon.
(If you don't know why, ask me). Then round it up. If it isn't real
round at this point, take some time with grinder or file to make it
pretty good. Don't quench at any point in the process.
Now stick the hardy end into the hardy hole. You have a pointy thing
sticking straight up toward the ceiling. Mark it about 3" above the
anvil face, heat it up at the mark and bend it 90 degrees, so most of it
is in the same plane as the anvil face. Don't bother to heat treat.
You need a rounder tool, which looks like a steel cone. I made one from a
truck axle to go in the hardy hole. Get close on the horn, then bump the
work down on the rounder while it's hot. It's good to about an inch and
a half inside diameter. If you weld the eye closed first, you can just
drop it over the spike and drive it down all around until it's circular.
If you're trying to form the eye in the first place, then you'll need to
mount the spike horizontally, like a mandrel.
Welcome to the wonderful world of tooling fabrication.
The easiest way I know to make small rings is to use a piece of pipe or
round bar as a mandrel. Heat a long length of your ring stock, clamp it
against your mandrel in a vise (vertically) and just wrap the stock
around the mandrel. You need to get things HOT and work fast. Use a
hacksaw or thin cut off disc in a hand grinder to separate the rings.
Perfect rings in multiple!