Outside metal rod

I thread lots of 5/16 stainless rods to make into "U" clamps for ham antenna projects. Use a 7" EMCO lathe and a die in a holder in the tail stock. Guess you don't have a lathe.

Should also be able to hold it in a vice. Are you tapering the rod where the thread starts? That has to be done to get the die to begin making threads.

Paul

snipped-for-privacy@handyman.com fired this volley in news:XBFct.19873$ snipped-for-privacy@newsfe24.iad:

How much of it do you have to thread?

For hand-threading stainless, it's helpful to have progressive dies, but you're not going to find them in a hardware store, or at hardware store prices. Usually, it's pretty easy to thread on a lathe, unless you get careless and work-harden piece.

If you don't have a lot of it to do, it might be cheaper to take it to a local machinist and ask him to do it.

If you're wanting to thread the whole length -- it's available already threaded cheaper than you'll ever do it yourself.

The other option would be to use all-thread inside a piece of SS tubing cut to fit what would be the 'unthreaded' section.

LLoyd

Missing a lot of info. How long does the rod have to be? Would galvanized bolts work? How many rods are you wanting? What about aluminum? Brass? Stainless threaded rod. Zinc plated threaded rod?

The stainless rod you have is probably work hardened. How about heating up the end you are trying to thread with a propane torch to soften the rod you have. Anyway you get the idea, we can help more if we knew more.

Dan

Looking for 1/4" metal rod I can thread. These will be attached to wood so rusting or staining can be a problem since they will be outside. Got a piece of stainless, the softess I could get but it is too hard to thread, have a good vise but with all the pressure It won't hold in the vise. Even bought a new die and tapered the end first. Had tried aluminum but it makes dark stains. Not into metal stuff so don't know what to look for. Maybe something coated? Thanks.

Stainless is a bitch to thread, no question about it.

But I didn't have any trouble finding stainless all-thread on the web.

Here's 1/4-20 threaded 18-8, 36" long for about $6 each:

18-8 won't stay shiny when exposed to weather, but it won't rust either. It just gets a dark brown patina on it.

316, on the other hand, will stay pretty shiny, but I couldn't find it threaded under 3/8" diameter.

Tom

Although not cheap, brass rod should do nicely and is pretty impervious to weather.

Wasnt he going to bend it after it was threaded?

Wont work with brass. Bronze..maybe

Gunner

Bronze is usually used in marine applications. Check at Jamestown for the item you need, A.

They probably have bronze allthread, too. (Entirely threaded rod.)

If it is for a boat then use 316 stainless as it is far more "stainless" than other common stainless :-)

As for threading. Try to file the end of the rod that you are planning on threading. If a file cuts it easily than your problem is the vise not the threading.

As JB says, 316 stainless if you want it to be stain-free.

I didn't notice if this is for fresh water or salt, but if it is for salt water use and it has any load on it, anything but 316 will develop stress-corrosion effects that can drive you nuts. Even if strength isn't an issue, a stressed piece of 304 in salt water will probably get rust spots or streaks on it.

Sure you're not mixing up stress corrosion and crevice corrosion? Both

304 and 316 are prone to stress corrosion. 316 does resist crevice corrosion and pitting better than 304.

As far as cosmetic rust spots go in a marine environment, for stuff out in the open and above the water line, the finish can make a bigger impact on rust spotting than the the difference between 304 and 316. It's tough to distinguish between 304 and 316 for parts that are highly polished and not exposed to stagnant water.

Stress corrosion is blamed for rusting of sailboat rigging and similar applications. It's not something I learned from materials science but rather something I learned as a sailor. I don't know what the mechanism is. But the story is that 304 gives problems, and 316 does not. I've seen it, but the descriptions come from experieced boating people I've known, not from materials scientists.

I don't have experience with that, but I'll take your word for it. Passivating and the quality of the steel are issues, too.

There is something wrong with your threading technique or tools if you can't thread a piece of 304 or 316 rod. It is not at all hard to thread.

With threading tools, I would first check that your thread die is proper quality.. With a cheap one it may well be that you can't make a single thread to even steel.. Get a good one.

Of course, if you don't know the material of the rod (mystery metal from junkyard), it could be some very hard material.. In this case, get proper 316 rod.. The file test is also a good idea - you should be able to file it easily..

Kristian Ukkonen.

I worked in boatyards for several years after college, then ran a custom marine hardware fab business for several more years. It drove me nuts that it seemed the answer to every materials question was "316 SS," even from folks I had a lot of respect for.

This is what the corrosion volume of the ASM Handbook says regarding

304/316 and stress corrosion: "The common austenitic grades, AISI types 304 and 316, are especially susceptible to chloride SCC."

But it also says that stress corrosion is generally not a problem in the environment that standing rigging is typically exposed to: "Stress-corrosion cracking is generally not a concern when austenitic or ferritic stainless steels are used in atmospheric exposures. Several austenitic stainless steels were exposed to a marine atmosphere at Kure Beach, NC. Annealed and quarter-hard wrought AISI types 201, 301, 302, 304, and 316 stainless steels were not susceptible to SCC."

OK, but to what do you attribute that "drooling rust" that appears on stressed sheet-metal clevices, shackles, and so on?

Unfortunately I don't have the ferrous volume of ASM Metals Handbook or I'd look it up myself.

If it's drooling rather than surface spotting it may be coming from the load bearing surfaces in the joints. As the rigging works there's bound to be galling or wear that'll break the passive layer and create scratches that are going to continue rusting as long as there's movement in the joint.

The passages I quoted are from Volume 13 - Corrosion.

That sounds reasonable.

I *definitely* don't have that one.

It doesn't seem to work that way in practice. One very seldom finds rust of any consequence on the pins and bolts that hold the rigging to the mast or to the rigging screws. In fact, stainless rigging does not seem to be particularly prone to corrosion. My experience was that bronze rigging screws required more attention than the stainless rigging :-)

Well, I've certainly seen it, on lighweight rigging used on planing dinghies and such. It appears to be cosmetic.

As for the grades of stainless used, again, I can only go on what other sailors, mostly with more saltwater experience than I have, have told me.

I had a Cape Dory Typhoon on Barnegat Bay for some years but rusting stainless was never a problem. Cape Dory doesn't spare expense on anything.