Williams all-thread rebar - thread form?

[gregormarwick]

I have been asked to quote on a part that connects to this stuff. I found it, with no real details, on their website.

The drawing calls out:

2 1/2" REBAR THD TOMATCH "WILLIAMS
GRADE 75 ALL-THREAD
REBAR"

Internal thread, to screw onto the rebar.

To add to the fun, the thread is 9.5" deep, blind hole.

Does anyone have any real data on this thread? Looks like it's just a semi-circular cross section, what size, pitch etc. I have no idea.

 

[DDoug]

I have been asked to quote on a part that connects to this stuff. I found it, with no real details, on their website.

The drawing calls out:

2 1/2" REBAR THD TOMATCH "WILLIAMS
GRADE 75 ALL-THREAD
REBAR"

Internal thread, to screw onto the rebar.

To add to the fun, the thread is 9.5" deep, blind hole.

Does anyone have any real data on this thread? Looks like it's just a semi-circular cross section, what size, pitch etc. I have no idea.

Maybe ?
McMaster-Carr

 

[Bill D]

sounds like it could be a API thread?
Bill D

 

[Rob F.]

Ask client why it needs to be 9 1/2"? The 2 1/2" Williams couplers are only 8" long and the bars go in 1/2 way so full strength is only 4" of threads. Looks like part #R62-20.
Per website:
All Couplings and Hex/CollarNuts exceed 100% of the bar’s published ultimate strength and meet ACI 318Section 25.5.7.1 for mechanical rebar connections.

First time I saw that stuff I thought it was a ballscrew, very similar form.

 

[gregormarwick]

Thanks for the replies. From what I can tell it's not the same as coil thread, and it's definitely not API.

Ask client why it needs to be 9 1/2"? The 2 1/2" Williams couplers are only 8" long and the bars go in 1/2 way so full strength is only 4" of threads. Looks like part #R62-20.
Per website:
All Couplings and Hex/CollarNuts exceed 100% of the bar’s published ultimate strength and meet ACI 318Section 25.5.7.1 for mechanical rebar connections.

First time I saw that stuff I thought it was a ballscrew, very similar form.

Rob, the thing goes underwater, so maybe the length of thread is to compensate for corrosion over time. Also it's load bearing - I don't know exactly what it's for, but I'm told it's an anchor point sticking out of concrete on the floor of an artificial lake or dam that they attach buoys or something to.

Do you know anything about the thread itself? Any idea if they'd be forthcoming with data if I contacted them?

 

[Red James]

If thread data is not available, you might use their coupling nuts and weld on whatever you want to adapt to your parts.

 

[Joe Gwinn]

When I googled on "williams all-thread" (without the quotes), a likely-looking suspect came up. Is this it?

Uploader

Uploader

 

[Rob F.]

Thanks for the replies. From what I can tell it's not the same as coil thread, and it's definitely not API.



Rob, the thing goes underwater, so maybe the length of thread is to compensate for corrosion over time. Also it's load bearing - I don't know exactly what it's for, but I'm told it's an anchor point sticking out of concrete on the floor of an artificial lake or dam that they attach buoys or something to.

Do you know anything about the thread itself? Any idea if they'd be forthcoming with data if I contacted them?

That makes sense if used underwater. The threads used on reusable concrete form screws are that shape to make it easy to clean off dry concrete, almost self cleaning. Unlike a vee thread where grit will get locked in and wedge the threads tight.
The underwater thread will surly collect grit and corrosion and this thread form has a better chance of coming apart down the road than a standard thread.

This is probably a similar pitch, from the link:
"Knuckle threads are an unusual highly rounded thread form. The large space between the rounded crests and roots provides space for debris to be shifted to not interfere with the thread, making this form resistant to debris and thread damage."
Knuckle thread - Wikipedia

Look at the reference at the end of the wiki page for more places to look.

Have you called the company and asked about them making you longer couplers? Just weld a stub of the rebar in the end to cap it off? Or thread the end for a plug, maybe pipe threads (or?), if no welding?

 

[gregormarwick]

I haven't contacted them yet simply because I don't expect much cooperation, but of course I can do.

Welding is not so simple, as the parts supposed to be made from forged 4340QT.

 

[kb0thn]

We anchored a 120' tower to bedrock using a bunch of engineer specified Williams components. Williams was reasonable to work with. It was a tiny job for them, but they appreciate that once an engineer specifies Williams parts, somebody has to be able to buy them and install them regardless of the job size.

I think I would pick up the dreaded phone and give them a call. If they won't provide thread specs, I think they would make the custom part for you. It's all made in Oregon, if I recall correctly.