Structural Screws Shear Strength: Insights and Data

Choosing the right screws is crucial for construction projects. The durability and safety of any build, whether residential or commercial, depend on these small yet vital components. Structural screw shear strength plays a significant role in providing robustness and reliability in various applications.

Choos­ing the right screws is cru­cial for con­struc­tion projects. The dura­bil­i­ty and safe­ty of any build, whether res­i­den­tial or com­mer­cial, depend on these small yet vital com­po­nents. Struc­tur­al screw shear strength plays a sig­nif­i­cant role in pro­vid­ing robust­ness and reli­a­bil­i­ty in var­i­ous applications.


With a wide range of options avail­able, it’s impor­tant to under­stand their shear strength and ver­sa­til­i­ty. This arti­cle pro­vides builders and con­trac­tors with a com­pre­hen­sive guide to mak­ing informed deci­sions for their con­struc­tion needs.

Understanding Structural Screw Shear Strength and Its Measurement

Shear strength is a crit­i­cal para­me­ter that describes a screw’s abil­i­ty to resist forces that cause it to slide or shear off at the point where it joins two mate­ri­als. This mea­sure is vital in ensur­ing the dura­bil­i­ty and safe­ty of con­nec­tions in con­struc­tion projects.

How Shear Strength Is Measured

The shear strength of struc­tur­al screws is deter­mined through a test­ing process where a force is applied par­al­lel to the screw’s axis. The key steps include:

  • Set­up: The screw is placed in a test­ing machine designed to apply a par­al­lel force.

  • Force Appli­ca­tion: Force is grad­u­al­ly increased until the screw fails or shears. This force is applied at a con­trolled rate and the max­i­mum load the screw can with­stand before fail­ure is recorded.

  • Mea­sure­ment: The crit­i­cal val­ue not­ed is the max­i­mum load capac­i­ty, mea­sured in pounds-force (lbf). This fig­ure rep­re­sents the direct load the screw can sup­port before it shears off.

Significance of Measurement in LBF

Mea­sur­ing shear strength in LBF offers a straight­for­ward under­stand­ing of a screw’s load capac­i­ty. This approach is prac­ti­cal, and it pro­vides direct insights into the per­for­mance of fas­ten­ers under oper­a­tional stress­es. It sim­pli­fies the selec­tion process for engi­neers and builders and ensures that the cho­sen screws can with­stand the expect­ed loads and con­tribute to the struc­tur­al integri­ty of the construction.

This method empha­sizes the direct load-bear­ing capac­i­ty of screws to aid in the design and con­struc­tion of safer, more reli­able struc­tures by ensur­ing that all fas­ten­ers meet the required per­for­mance standards.

The Structural Screw Shear Strength of The LOK Fastener Series: Engineering Excellence for Every Joint

Fas­ten­Mas­ter pro­vides com­pre­hen­sive struc­tur­al shear strength infor­ma­tion for its LOK screws to help builders and con­trac­tors make data-dri­ven decisions. 

List­ed below is an expla­na­tion of each Fas­ten­mas­ter struc­tur­al screw that includes their appli­ca­tions, dimen­sions, and shear strength

Timber LOK Drawing

Tim­ber­LOK is the solu­tion for secure­ly attach­ing rafters, truss­es, head­ers, and stair stringers that fea­ture sharp points and aggres­sive threads for fast pen­e­tra­tion into dense woods to stream­line the instal­la­tion process.

TimberLOK Dimensions

  • Unthread­ed Shank Diam­e­ter: .189 (Inch)

  • Out­side Thread Diam­e­ter: .260 (Inch)

  • Allow­able Ten­sile: 1,300 (LBF)

  • Allow­able Shear: 940 (LBF)

View the Tech­ni­cal Eval­u­a­tion Report™ on the Tim­ber­Lok Fastener.

HeadLOK: Heavy-Duty Versatility

Head LOK Drawing

Head­LOK stands out for its ver­sa­til­i­ty across appli­ca­tions, includ­ing deck fram­ing and wood-to-wood con­nec­tions by offer­ing a high­er design shear than tra­di­tion­al lag screws to boost con­nec­tion strength.

HeadLOK Dimensions

  • Unthread­ed Shank Diam­e­ter: .19 (Inch)

  • Out­side Thread Diam­e­ter: .260 (Inch)

  • Allow­able Ten­sile: 1,215 (LBF)

  • Allow­able Shear: 965 (LBF)

View the Tech­ni­cal Eval­u­a­tion Report™ on the Head­LOK Fastener.

LedgerLOK: Ledger Board Security

Ledger LOK Drawing

Designed for attach­ing deck ledger boards with effi­cien­cy, Ledger­LOK fea­tures a unique flat head and TORX® ttap® dri­ve sys­tem for a seam­less fin­ish that blends aes­thet­ics with robust fas­ten­ing performance.

LedgerLOK Dimensions

  • Unthread­ed Shank Diam­e­ter: .228 (Inch)

  • Out­side Thread Diam­e­ter: .305 (Inch)

  • Allow­able Ten­sile: 1,833 (LBF)

  • Allow­able Shear: 1,235 (LBF)

View the Tech­ni­cal Eval­u­a­tion Report™ on the Ledger­LOK Fastener.


Versalok drawing

VersaLOK Dimensions

  • Unthread­ed Shank Diam­e­ter: .228 (Inch)

  • Out­side Thread Diam­e­ter: .305 (Inch)

  • Allow­able Ten­sile: 1,833 (LBF)

  • Allow­able Shear: 1,235 (LBF)

View the ICC-ES Eval­u­a­tion Report on the Ver­sa­LOK Fastener.

ThruLOK: Through-Bolt Alternative

Thru Lok Drawing

An effi­cient replace­ment for through-bolts, Thru­LOK is ide­al for mul­ti-ply beams, deck posts, and car­ry­ing beams that com­bine hold­ing pow­er with ease of instal­la­tion for scal­able appli­ca­tions and is backed by com­pre­hen­sive test­ing and code compliance.

ThurLOK Dimensions

  • Unthread­ed Shank Diam­e­ter: .228 (Inch)

  • Out­side Thread Diam­e­ter: .310 (Inch)

  • Allow­able Ten­sile: 1,970 (LBF)

  • Allow­able Shear: 1,235 (LBF)

View the Tech­ni­cal Eval­u­a­tion Report™ on the Thru­LOK Fastener.

FlatLOK: Multi-Ply Mastery

Flat LOK Drawing

Specif­i­cal­ly designed for mul­ti-ply dimen­sion­al and engi­neered wood con­nec­tions, Flat­LOK facil­i­tates sin­gle-sided instal­la­tions that are suit­able for var­i­ous ele­va­tions. It com­plies with the lat­est ICC stan­dards to ensure safe use in ACQ or treat­ed lumber.

FlatLOK Dimensions

  • Unthread­ed Shank Diam­e­ter: .227 (Inch)

  • Out­side Thread Diam­e­ter: .322 (Inch)

  • Allow­able Ten­sile: 1,940 (LBF)

  • Allow­able Shear: 1,230 (LBF)

View the Tech­ni­cal Eval­u­a­tion Report™ on the Flat­LOK Fastener.

Comparative Insights: LOK Line Versus Traditional Fasteners

When com­pared to tra­di­tion­al lag bolts, Fas­ten­Mas­ter LOK screws stand out for their shear strength, ease of instal­la­tion, and ver­sa­til­i­ty. The LOK line demon­strates a com­mit­ment to inno­va­tion by offer­ing solu­tions that not only meet but exceed the demands of mod­ern con­struc­tion practices.

Installation Guidelines and Best Practices

For opti­mal results, it’s impor­tant to fol­low Fas­ten­Mas­ter’s rec­om­mend­ed instal­la­tion guide­lines and best prac­tices. Using the right tools and tech­niques ensures that each screw per­forms to its full poten­tial in order to con­tribute to the over­all strength and dura­bil­i­ty of the construction.

Secure Your Build with Precision and Strength: FastenMaster LOK Solutions

Every detail mat­ters in con­struc­tion, espe­cial­ly the shear strength of struc­tur­al screws, which under­scores the neces­si­ty for safe­ty in projects. 

The LOK line of struc­tur­al screws by Fas­ten­Mas­ter stands out for its excep­tion­al shear strength, user-friend­ly design, and depend­abil­i­ty to pro­vide endur­ing sta­bil­i­ty for your projects.

Reach out to us today for more details!