Greg's FAQs

Galvanizing Bolts for Pressure Treated Wood

Are current ASTM galvanizing standards suitable for use with the new chemicals being used in pressure treated wood? Some people have told me I need to use double or triple dipped fasteners. Is this true?

Since the new chemicals (alkaline copper quat [ACQ], copper azole [CBA-A and CA-B], and sodium borates [SBX]) now being used in pressure treated wood have been shown to be up to two or three times more corrosive than the previously used chromate copper arsenate (CCA), the recommended galvanizing thickness for materials being used with the... Read more

Galvanized Bolts and Chased Threads

Can threads be chased after hot-dip galvanizing for proper nut fit?

Absolutely not! Externally threaded fasteners should never be “chased”. During the hot-dip galvanizing process, excess zinc has a tendency to build up in the threaded portion of a fastener. Chasing threads is a term used to describe re-cutting threads after galvanizing to remove this excess zinc gained during the galvanizing process. Chasing threads will not... Read more

SAE Grade 8 markings

What visual markings does a grade 8 piece of all thread rod have that would identify it as being so? Meaning, how can you tell just by looking at a stick that it's grade 8?

Most grade 8 bolts require a permanent marking symbol that is designated by 6 radial lines. However, the SAE J429 specification that covers grade 8 fasteners does not require grade markings for studs (fully threaded rods) or slotted and cross recess head products. Therefore, you will not be able to visually identify a threaded stud... Read more

ASTM and SAE Differences

What are the main difference between ASTM 307 GR.B, ASTM A449, and SAE Grade 5 bolts?

There are two specifying bodies when it comes to fasteners. ASTM (American Society for Testing and Materials) covers primarily bolts and fasteners for construction applications. SAE (Society of Automotive Engineers) covers fasteners for automotive, machinery, and OEM applications. ASTM A307 grade B is made from a low carbon steel and is a relatively low strength... Read more

ASTM A325 vs A449

I have two items that use 1" bolts, one is ASTM A325 and the other is ASTM A449, I would like to just use one. Which is the one that meets or exceeds the other?

These bolts are identical with regard to strength and chemistry. There are very minor differences in the hardness requirements, but the proof load, tensile, and yield strength requirements are the same. From a manufacturing standpoint, we make these bolts using the same raw material and the same heat treating and production methods. Our strength by... Read more

Concerns Calculating Torque

How do I calculate torque for construction fasteners?

Torque is a difficult value to calculate accurately, especially for construction fasteners and should be used cautiously. The primary challenge is accounting for environmental factors, coatings, and a number of other variables including surface texture, material hardness, and thread series. In most situations, it is challenging to give reliable allowable torque values for bolted assemblies.... Read more

Hex Bolts vs. Hex Cap Screws

What are the differences between a hex cap screw and a hex bolt?

These terms are often incorrectly used interchangeably. The most basic difference between a cap screw and a bolt is the way in which these fasteners are installed. Technically, a bolt is installed by turning a nut to tighten the fastener, while a cap screw in installed by turning the head of the bolt to assemble... Read more

Lag Screw Shear Strength

How do I determine the shear capacity and strength of lag screws?

Unfortunately, we have no specific data to answer this question. First, “standard” lag bolts that are readily available in the marketplace are ungraded, meaning they are not manufactured to any ASTM specification and have no verifiable mechanical requirements. Therefore, it is impossible to determine the strength characteristics of a lag screw unless they are custom... Read more

Grade 55 Steel Properties

Can I use ASTM 108 Round Bar, a CF-1018 round bar, for F1554 Grade 55?

The problem with ASTM A108, 1018CF is that there are no mechanical requirements and typically the test reports that accompany this steel reflect the chemistry only and not the strength of the steel. Test reports will need to accompany this material that reflect all four of the values listed below, and these values will need... Read more

Malleable Iron Washer Details

What are the purposes for the different components in malleable iron washers (MIW)

For many years a malleable iron washer has been a common component in heavy timber and marine construction. With a large bearing surface and thick cast design they help prevent the bolt head or nut from pulling through wood connections. There are two common types of MIW. One style of malleable washer is produced in... Read more