Comments on: Rolled vs Cut Thread Bolts

By: Jonathan Waltner

Jonathan Waltner — Wed, 06 Jan 2010 16:20:41 +0000

@Freddy Keener – Cutting the threaded portion of the bolt won’t have any effect on the strength of the bolt. The only factor to worry about in a situation like that is that you leave the amount of thread needed to achieve minimum thread engagement.

By: Freddy Keener

Freddy Keener — Tue, 05 Jan 2010 01:24:22 +0000

Does a rolled thread fastener become weaker than its equivalent cut thread fastener when cut to a shorter length?

By: Ken Rollston

Ken Rollston — Wed, 11 Nov 2009 00:53:43 +0000

why don’t you roll thread anything over 150KSI??

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.