Lag Screws: Dimensions and Mechanical Properties | AFT Fasteners

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Lag Screws: Dimensions and Mechanical Properties

AFT Fasteners Lag Screws Specs

Hex Lag Screws: Dimensions (ASME B18.2.1-1996)

Basic Product Diameter

Threads Per Inch  Body or Shoulder Diameter (E) Width Across Flats (F) Width Across Corners (G) Head Height (H) Shoulder Length (S)
Max Min Basic  Max  Min Max  Min Basic Max Min Min
#10 .1900 11 .199 .178  9/32 .281 .271 .323 .309 1/8 .140 .110 .094
1/4 .2500 10 .260 .237  7/16 .438 .425 .505 .484 11/64 .188 .150 .094
5/16 .3125 9 .324 .298  1/2 .500 .484 .577 .552 7/32 .235 .195 .125
3/8 .3750 7 .388 .360  9/16 .562 .544 .650 .620 1/4 .268 .226 .125
7/16 .4375 7 .452 .421 5/8  .625 .603 .722 .687 19/64 .316 .272 .156
1/2 .5000 6 .515 .482  3/4 .750 .725 .866 .826 11/32 .364 .302 .156
5/8 .6250 5 .642 .605 15/16 .938 .906 1.083 1.033 27/64 .444 .378 .312
3/4 .7500 4-1/2 .768 .729 1-1/8  1.125 1.088 1.299 1.240 1/2 .524 .455 .375
7/8 .8750 4 .895 .852  1-5/16 1.312 1.269 1.516 1.447 37/64 .604 .531 .375

 * Click on the basic product diameter to find products.

Lag Screws: Tolerance on Length
Nominal Screw Size Nominal Screw Length
Up to 6 in Over 6 in
1/2 and smaller
+/- 0.12 +/- 0.25
Over 1/2 +/- 0.25 +/- 0.25

 

Lag Screws: Performance & Mechanical Specs

Description

A full-bodied bolt with hex head, spaced threads and a gimlet point.

Applications

Steel, Electro-plated Zinc: For use in wood in non-corrosive environments

Steel, Hot-dip Galvanized: For use in corrosive environments

Stainless Steel: Has superior corrosion resistance to galvanized steel bolts.

Material

Steel: AISI 1006-1022 or equivalent steel

Stainless Steel: 18-8 stainless

Heat Treatment

Stainless: The austenitic alloys develop their strength through work hardening during the fastener manufacturing process, as seen from the hardness properties below. The only heat treatment normally available on austentic stainless alloys is annealing, which is done at approximately 1900 Degrees (F) to a dead soft condition and is not normally thermally reversible.

Hardness

Steel: Rockwell B70-B100

Stainless Steel: 100,000 - 125,000 psi

Minimum Length of Thread

The minimum length of thread shall be equal to 1/2 the nominal screw length plus .50 inches, or 5.00 inches, whichever is shorter. Screws too short for this formula shall be threaded as close to the head as practicable.

 

 

Fully Threaded Lag Screws Specs

Fully Threaded Hex Washer Lag Screws: Dimensions (Low Carbon & Grade 5)

Screw Diameter

 

Threads per Inch

 
Head Height (H) Width Across Flats (F) Washer Diameter (C) Washer Thickness Major Diameter
Max Min  Max  Min Max  Min Max Min Max Min
1/4 10 .190 .172 .437 .429 .625 .610 .060 .050 .260  .237
5/16 9 .230 .200 .437 .429 .625 .610 .060 .050 .324 .298
5/16-High Head 9 .312 .300 .437 .429 .625 .610 .060 .050 .324 .298

  

Fully Threaded Hex Washer Lag Screws: Performance & Mechanical Specs (Low Carbon & Grade 5)

Description

A fully threaded fastener with a spaced thread pitch, tapered point, and an integrally formed hex washer head with an indented top surface.

Applications

Designed specifically for attaching track brackets and flag brackets of garage door assemblies to wooden door jambs.

Material

AISI 1018 or equivalent steel

Tolerance on Length

+/- .012