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?
Thanks, Mitch
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.
Bill Ranck Blacksburg, Va.
Go to
-Doug
Another method would be to cut the head off a bolt or threaded rod and weld it to the unthreaded portion.
Just an idea.
Oops! Didn't see the smooth part. :-)
Hmm, and excuse to buy a welder or an excuse to buy a tap and die set . . . decisions, decisions. ;-)
Bill Ranck Blacksburg, Va.
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.
Vic 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.
Dave Hinz
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 minutes later.
No icky cutting oils, no expense for a tool that you will never use again. Ed
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.
Bill Ranck Blacksburg, Va.
Good point. Food and/or drink is always a valuable tool for such situations.
But...must...buy...tools... I'm not sure how to mentally arrange this. Clever approach vs. new tools. I thought "buy 'em all" was the general advice here?
Dave Hinz
VRadin wrote in news:MPG.1afb0504a27cde0e989945@206.141.193.32:
That's definately the way to go. That way you can use all manner of weird threads (1/2 - 40? 11tpi Acme?) and ensure no-one else wanders off with your stuff.
John
remember to back the die off to clear out the chips frequently. like every quarter turn or so.
You buy a tap and die set.
A "die" will cut threads on bar stock. Use cutting oil.
I don't think that'll stop them from being taken, what it will do is cause them to end up in the trash when the new "owner" can't find any attachments to fit.
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.
hex
-30-
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 die.
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