I need to use steel rod on a gizmo I'm making. It needs to be smooth
along its length but the ends need to be threaded. I don't know what
lengths of rod I'll need but there will be enough different lengths
that I will need to cut it myself. What tool do I need to put threads
on the ends? How do I do this?
You want a "die", which kind of looks like a nut, but has sharpened teeth
to cut the thread. Use cutting fluid (motor oil works in a pinch) to
keep things lubricated, & just thread it on. A good hardware store
should have an assortment and be able to advise you what thread you
should use for your application.
Dave "...has a metalworking shop as well" Hinz
You need a die. It's the compliment to a tap. You can
buy individual dies, and a separate handle to mount it in,
at a hardware store. Most standard thread pitches are
readily available. You can also buy tap and die sets.
This might be more economical if you have need for more
than one size thread.
You can get a decent used South Bend metal lathe from almost any school
ripping the heart and soul out of a shop program. And since we're
looking at new tools anyway, may as well go for some medium-sized iron.
Still looking for a place to put that South Bend ;-)
The die would be the way to do it in this case, but no reason
to not also buy the welder.
If you don't plan to use taps & dies often, or even if you do,
I'd suggest buying a _good_ die for this purpose, rather than
getting an entire set of less-than-fantastic tools. My dad,
well, he shops for price sometimes. I borrowed a die from him for
a size I happened not to have, and it was literally unusable
(and it came in a set bought at the BORG). It was off-center,
the teeth were different sizes and profiles, and there was no
lead-in taper so it was impossible to start unless I tapered the
shaft. With a real die, it was a 30 second job, with the one
from the BORG it was an impossible one. Not specifically a
Home Depot issue, but more a "avoid cheap tools in this instance"
kind of warning.
No tools needed. You take the rod to work with you. Take a couple of
coffees down to the maintenance guys and ask them if it can be done. They
will say sure, how long do you want the thread? Tell them. Pick it up ten
No icky cutting oils, no expense for a tool that you will never use again.
Ha! Reminds me of the days when I worked for a research department
at the university. They had a machine shop and two machinists who's
job it was to make up fixtures and gadgets for experiments. I needed
a drill bit one day to put a hole in some aluminum diamond plate
on an instrument truck. Went in to the shop to ask the machinist for
a drill bit. He asked what it was for and then proceded to regrind
the profile of the bit to work better in aluminum. Those guys were
amazing. They would have had no problem cutting threads on round stock
to any pitch and length needed, and would have had chamfered
the end of the thread slightly to make starting the nut easier, and
probably a couple other nice touches I might or might not notice.
firstname.lastname@example.org wrote in message wrote in message ...
Similar experience, only the shop had 4-5 guys on staff and I was a
grad student. I approached things a little differently: I always
asked HOW they would recommend doing something. The pro's were
always interested in teaching if you were willing to learn. Very few
people can come up with custom equipment designs as screwed up as
physicists who haven't spent time making their own parts.
The department also had a reasonably well stocked shop for student use
-- basically old but sound machines with nary a digital readout to be
found. Learned a lot of design by doing my own machining. Of all
the things in grad school time spent in the shop is probably what I
miss the most. Since the current choice is working in wood I don't
have room for metal tools.
P.S. to keep this at least marginally on topic:
to the OP -- go get a die. If you haven't experience with a die, then
the posts elsewhere in this thread about cutting threads on a lathe
are a little far off. It's not all that hard to cut threads with a
good lathe, but still significantly harder than cutting threads with a
You've already heard about what tool to use. You might also consider
using a bolt of the proper length, cut off the head, then thread the
unthreaded end. End result, a smooth shank thats threaded on both ends
and of sufficient strength (probably) for the project at hand. Cheaper
than buying unthreaded rod and stronger too.
Mitch from NYC wrote:
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