Historic Turnbuckles capacity

[Bridge_Man]

Hi,

I have a turnbuckle that am trying to get its capacity, the only thing I know about this turn buckle is it's size (Std 1-7/8) , its weight (12 lb), and the fact that it was made in 1928, no other info about what standard did it follow or anything else.

any recommendations on how to calculate its capacity, any historic references?

Thanks

 

[WinelandV]

SlideRuleEra has a page that has a bunch of vintage/historic resources.

 

[JStephen]

My 1948 AISC handbook gives dimensions (but not capacities) for turnbuckles and says they are based on Cleveland City Forge Company standards, and that similar products of other companies are essentially the same.
And it looks like Cleveland City Forge is still around, so they might be the ones to ask:

https://www.clevelandcityforge.com/industrial-fasteners/structural-steel-turnbuckles/

 

[rb1957]

wouldn't the turnbuckle be as good as the thread ?

another day in paradise, or is paradise one day closer ?

 

[Bridge_Man]

Thanks to all

rb1957, agree, it should be even better, but I need to show that it's actually better

Winelandv, and JStephen, thank you so much, I will use the material used at that time mentioned in those manuals with the associated dimensions of the turnbuckle I found in those manuals to approximate a rough and conservative capacity.

 

[hokie66]

In my experience, old turnbuckles, and most new ones, do not have equivalent capacity to the rods they connect. If you want one equivalent to the rod, you can make one, typically out of square or hexagonal stock. But if a reputable manufacturer has test data to show the capacity of its turnbuckles, use it.

 

[JStephen]

In some cases, the turnbuckles may use upset ends, which would help on the capacity.
Some of the old water-tower turnbuckles have ends that come out and form two little loops that go around a pin. Those may have been hand-forged, I'm not sure if that was ever a manufactured part.

 

[rb1957]

how can the turnbuckle be better than the thread ? Once the thread fails, the turnbuckle is in two (or several) pieces ...

another day in paradise, or is paradise one day closer ?

 

[JStephen]

Edit: Sorry, I was just trying to show the end pieces, and added the turnbuckle per the comment below. These were pictures of the overall tank, so they are cropped severely to get the items in question, which is why they are not so sharp. The turnbuckle looks like those rods may have upset ends, but I can't tell for sure. The outer ends look like the funky forged double-loop I mentioned, but I can't tell for sure- it may be a welded-up assembly. The reason I show them, without having some way of evaluating the strength of the end connections, it may not matter so much what the turnbuckle capacity is.

 

[hokie66]

Those are not turnbuckles. They are eye bars. There may be a turnbuckle on the bar somewhere, but I can’t see it in the picture.

 

[rb1957]

so turnbuckle don't tend to fail in the threads ? um, wouldn't've thought that.

another day in paradise, or is paradise one day closer ?

 

[Bridge_Man]

Thanks all

JStephen, man this is quite close to what am working on, I do have upset ends where a turnbuckle connects to, the rod itself will fail way before the turnbuckle will, I only needed to show that.