Hex Lag Screw

Hex lag screws are the best in the industry with six sided heads. A lot of bolts including ASTM A307 Grade A bolts and SAE hex bolts require a standard hex head. As far as specifications such as A307 grade B, A490 and A325 that require a heavy hex pattern is concerned, referring dimensional tolerances for structural bolts and/or heavy hex bolts is an ideal solution.

Manufacturing

BBI manufactures superior quality lag screws. With a diameter of 1/2″ – 1-1/2″, these bolts fulfill most specifications of the ASTM, SAE and AASHTO. In fact, we can even create special tooling to help produce nonstandard bolt heads / head dimensions with your preferred logo and/or name.

Non-standard lag screws manufactured by BBI generally have a semi-cone point rather than a cone point or a gimlet. It’s crucial to sport a full point as a pilot hole that’s as large as the root diameter of the lag screw needs to be drilled prior to installation. Moreover, in small diameter screws, to facilitate installation without a pilot hole, a gimlet point is designed. Lag screws in the above mentioned diameters generally do not demand a gimlet point because much torque is needed to install large screws if it’s not chosen to drill a pilot hole in the beginning. If a pilot hole is absent, the heads of screws often break before installation of the lag screw.


Stock

Diameters: 1/2″ – 3/4″
Lengths: 18″ maximum
Origin: Import
Finish: Plain and hot-dip galvanized

Standard Thread Length

The minimum thread length shall be equal to one-half the nominal screw length plus 1/2″ or 6”, whichever is less. One should consider longer than standard thread lengths for lag screws which are extremely long.

Note: Hex lag screws larger than 3/4″ in diameter and all square lag screws are rarely available in the marketplace as a stock item.

Hex Lag Dimensions

Click table to show drawing
Bolt DiameterDFHThreads Per InchThread Dimension
Body DiameterWidth Across FlatsHead HeightPitchTFTDTR
MaxMinFlat At RootDepth of ThreadRoot Diameter
1⁄20.5150.4823⁄411⁄3260.1670.0720.0640.371
5⁄80.6420.60515⁄1627⁄6450.2000.0860.0770.471
3⁄40.7680.72911⁄81⁄241⁄20.2220.0960.0850.579
7⁄80.8950.85215⁄1637⁄6440.2500.1080.0960.683
11.0220.97611⁄243⁄6431⁄20.2860.1230.1100.780
11⁄81.1491.098111⁄163⁄431⁄40.3080.1330.1190.887
11⁄41.2771.22317⁄827⁄3231⁄40.3080.1330.1191.012
13⁄81.4041.34621⁄1629⁄3230.3330.1430.1281.119
11⁄21.5311.46921⁄4130.3330.1430.1281.244
Dimensions per ASME B18.2.1 2003

Stock Lag Screws

Length (in.)Diameter
3/8″1/2″5/8″3/4″
PlainGalv.PlainGalv.PlainGalv.PlainGalv.
11137511376––––––
11⁄41137711378––––––
11⁄211379113801890418905––––
13⁄41138111382––––––
2113831138411413114141144711448––
21⁄2113851138611415114161144911450–19575
31138711388114171141811453114541148911490
31⁄21138911390114191142011455114561149111492
41139111392114211142211457114581149311494
41⁄2113931139411423114241145911460––
51139511396114251142611461114621149711498
51⁄2113971139818906189071890818909––
61139911400114291143011465114661150111502
71140311404114331143411469114701150511506
81140711408114371143811471114721150911510
9––114391144011473114741151111512
101141111412114411144211475114761151311514
11––––18910189111891318914
121890218903114451144611479114801151711518
14––182661826711481114821152111522
16––182681826919597195451152511526
18––182701827119693196941152911530
20––––––1891518916
These sizes are readily available in the marketplace and baseline Bolt stocks many of them in varying quantities. If you require a size that is not listed, baseline Bolt will manufacture them.