Comments on: Rolled vs Cut Thread Bolts

By: Liz

Liz — Sat, 27 Jun 2009 12:56:55 +0000

Is there a visible difference between rolled and cut threads? I’ve heard that it may be possible to tell based on the curvature of the thread root, but I can’t find a source anywhere that says so either way.

By: Adam Oakley

Adam Oakley — Thu, 19 Mar 2009 18:11:36 +0000

ASTM allows full body A325 bolts to be roll threaded. However, reduced body roll thread, which is the process that Portland Bolt uses and is the topic of this article is not allowed. ASTM states that A325 and A490 structural bolts must meet the dimensional tolerances of ANSI 18.2.6 that would not allow the use of reduced body pitch diameter material. For A449 fasteners it references ANSI 18.2.1 for the dimensional tolerances. This specification allows a reduced body diameter to be used if the manufacturer and purchaser agree. Since the reduced body pitch diameter material is between the major and minor thread dimensions, it is usually allowed for most applications.

By: Jerry Hickey

Jerry Hickey — Thu, 19 Mar 2009 17:22:45 +0000

If you’re stating that A325 bolts should not be roll threaded. What is you opinion on roll threading non-head A449 bolts and A449 fully threaded studs?

By: Adam Oakley

Adam Oakley — Wed, 18 Mar 2009 22:24:30 +0000

Portland Bolt has two methods of threading bolts. Roll threading is mainly limited by diameter (up to 1") and material grade restrictions. This is a very fast way of threading large quantities and produces a very cost effective bolt. Cut threading is primarily used for bolts over 1" up through 6" in diameter, high strength fasteners, and smaller manufacturing runs. Since we have two threading options, the most effective method is selected for each order, saving customers time and money. We specialize in large non-standard anchor bolts for the light pole and traffic signal industry.

By: WILLIAM WADE

WILLIAM WADE — Wed, 18 Mar 2009 20:07:42 +0000

WHY IS PORTLAND BOLT LIMITED TO A MAXIMUM 1″ DIAMETER” I WOULD THINK IN THE CONSTRUCTION TRADE, BOLTS CAN GET UP TO 2 1/4″ IN DIAMETER..i.e TRAFFIC SIGNAL POLES.

By: Adam Oakley

Adam Oakley — Wed, 18 Mar 2009 18:30:37 +0000

Thanks for adding your expertise, Doug. You are correct no one should ever make changes to specifications without the engineer’s approval. An elaboration on note 5 under “Disadvantages of roll threading” briefly talks about this concern. We don’t have any engineers on staff and always recommend that they be consulted before any changes are made.

By: Doug

Doug — Wed, 18 Mar 2009 15:24:13 +0000

The shank diameter of bolts connecting timber components can be critical. Bending strength in longer bolts may control the capacity of the connector. A .912” diameter bolt through a 10 ¾” timber member would have ~18% less load capacity than a 1.000” diameter bolt. Rolled thread bolts should not be used in timber systems unless done so with the blessing of the designer/specifier.
Bolt design equations can be found ANSI/AF&PA NDS-2005, Part 11.3.

By: John G Asimou

John G Asimou — Mon, 02 Feb 2009 21:59:23 +0000

What is “pitch diameter”? What are the material diameters before threading for “strandard” sizes? Is there such a thing as a “handy dandy” chart/table? I run a service as “ask the metallurgist” for my firm and get asked quite often. thank you, JG

By: Adam Oakley

Adam Oakley — Tue, 11 Mar 2008 22:18:56 +0000

Darrell » I’m not familiar with the specification you reference in your question. Our knowledge is focused on construction fastener products and it sounds like this may be out of the scope what you’re researching. All roll thread product we provide are externally threaded. If you are not able to find an answer can I run this by operations manager.

By: Darrell

Darrell — Tue, 11 Mar 2008 16:06:22 +0000

I know you can make an acceptable external thread per ASE AS8879, but is this also true for an internal thread? The ones I’ve seen have the appearance of being double thd’d.,lacking material streangth near the pitch line.