Hi everyone-

I'm back to this bottomless pit of knowledge for another heapin' helpin' of your hospitality. This weekend we will be placing a new side sill and the needlebeams on our Lawndale boxcar. Very quickly, we will be needing to repair the truss rods which were torched when the car was converted to a storage building, and unfortunately, none of the queen posts survived.

In an ideal world, some of you museum folks might have some scrapped ones laying around that could find a good home here in NC. Otherwise, a nice, roughly dimensioned drawing or photograph, or even a scan of an catalog hardware page would be most helpful, as we have a very gifted machinist available to us.

Can anyone help us out in this regard? The truss rods are 1" diameter.

While we're at it, anybody have a source for turnbuckles appropriate for this size of rod?

Thanks in advance- all of the advice given on this board to our project has been incredibly helpful.

Best Regards,

Matt Bumgarner
Alexander Chapter NRHS

McMaster-Carr lists 1" turnbuckles. mcmaster.com and search for turnbuckle

I was also going to suggest McMaster Carr for the turnbuckles. For the truss rods you should be able to get the appropriate round stock and cut to length and bend without a lot of grief. Dies for threading - remember one of the turnbuckle ends is left handed.

The queenposts are probably more complicated. Some that IRM meeded - we made our own patterns, had them cast (two different projects) and then machined them. The dimensions vary widely in height from the needle beam. What is the size of the needle beam which I assume is wood and how are the posts to be fastened? How many are we talking about?

Bob Kutella

I have a couple of thoughts…

Many if not most truss rods had upset ends, i.e. the threaded portion of the truss rod was forged to a larger diameter prior to cutting the threads, so that the smallest diameter of the threaded section was still the core diameter… We recreated this by welding threaded stock onto our truss rods.

Here in California many narrow gauge cars didn’t have turnbuckles on the truss rods, depending on the ends to take up any slack. We worked up a clamp to allow us to put new truss rods into a car as halfs then weld in the center where a turnbuckle would have been.

I am currently making a pattern for a 6 inch queen post. Parts would probably be 6 months away. Alternately you can use weld-ups. If you go that route you can make them look like castings by careful grinding, tumbling and acid baths.

Finally, there is typically a casting on top of the bolster for the truss rod to bear on. It is called a truss rod bearing or truss rod saddle. I have a pattern for a California example.

PM me for details.

Bob-

The needlebeams are 4.5" wide, 8.5" deep. We'll need 8 queenposts, and honestly, I am guessing they are bolted on.

Randy-

I'll email you off list later in the weekend. Would be very interested in your patterns/castings. On the two outer truss rods, our truss saddles on the bolsters are in place and in great shape, other than some surface rust. On the two interior rods, there are some smaller saddles, but one is broken in half. None of these are bolted or fastened in place in any way, shape or form (other than a groove in the wood), and they are merely held in place by tension.

Thanks

Matt Bumgarner

I a machine shop the Lathe with hole thru the head stock of big the rod will let you to thread Left head by set the Lathe to left on the cutting.
I recommend that the support be provide to keep the length from sagging on the rod.

Randy,
I thought the threads were actually rolled, which results in a thread somewhat larger than the diameter of the rod, and the threads are considered stronger than cut threads because of the compression of the metal. Now, where you'd find the tooling to to that today, um, err, you're solution is probably the best one!
S'
David D.

Hi Jeff,
Yes, I know rolled threads are still commonly used on bicycle and other wheel spokes (somewhat in the size area you mentioned), but for the size of truss rods, I'm not so sure you'll find that easily available--but if it is (at a somewhat reasonable price & shipping expense), I'd think they'd get some biz from groups restoring early cars.

BTW, Rolls Royse used truss rods on their car frames up to the early 30s too!
S'
David D.

No reason you couldn't either weld up and turn the OD larger for the threads, or upset them at the forge. Either way you can turn the threads on in the lathe, or simply turn the ends to spec and thread with a die.

Truss rods, guys, not the space shuttle.

dave

Dave,
Well, it WAS the "space shuttle" of it's time!! :)
Yepper, that's why I said that Randy's idea of welding a larger rod was probably the most practical solution.
Hmm, could we then say we'd "Hot Rodded" it??
S'
David D.

I suspect we are seeing at least two ways of achieving the same result…

The term we find used for this on Carter drawings is “upset,” a blacksmith term meaning that you forge an item to a larger cross section… Our local blacksmith regularly upsets metal, but not in the sizes needed for truss rods. Voss (Railway Car Construction, 1893) says “The ends of the rods, when provided with a screw thread, must be enough enlarged to make their diameter at the bottom of the thread equal to that of the iron in the body of the rod.” (So the upset rods are not just California practice)

The Carter Bros plans for a gallows turntable (held by CSRM, found in a collection of papers from a San Francisco foundry/machine shop) show that each of the three pairs of truss rods get progressively larger as they radiate out from the tower, and that all have upset ends called out… All in all a relatively sophisticated bit of engineering, designed to reduce the amount of metal used to a minimum, at the cost of additional labor. These designs were not the space shuttle, but not just thrown together by a couple of local carpenters...

I have an older French hand made bicycle frame with “butted” tubes… the wall thickness was increased where the frame was brazed together to compensate for the reduced strength of the metal after being heated while reducing the overall weight.

I say the way to make 1" and 1- 1/4" is the use a Lathe with Headstock big to take the 1' and 1-1/4 thru the inside and the length of rod can be support while the Lathe is turn. The Lathe will make Left and Right hand thread
If you want small size like 5/8 a South Bend Lathe 9 will work. The Machine Shop can do it. The Lathe are cut, not thread rolling.

Stan

Randy,
Wow, what neat documents! The specification requiring the root of the thread to be no less than the diameter of the rod makes good sense, as the rod is only as strong as its smallest diameter
Ah yes, double-butted tubing, if I recall rightly, one of the favorites was Reynolds 531, besides being double-butted, it was a special alloy too. (I had a small repair shop in high school--not much competition in little Dunsmuir!--I should dig out my old catalogs and put then on eBay; they're probably "collectibles" now, NO not "antiques!")
S'
David D.