At my work place I came across a bunch of old lag bolts of different lengths and diameter that all have square heads instead of hex. I tried using different normal wrenches and sockets on them but none will fit right. I showed them and asked at the hardware store if they knew of a wrench or socket used for these and they said they said they'd never even seen square headed lag bolts. I googled a little and found that apparently these are outdated and rarely used nowadays. Any comments appreciated.

 

An open end wrench should work fine. I've seen/used those types of lag bolts but it's been awhile. A hammer helps to speed up their installation

 

You'll want to find an old fashioned square wrench



if you can't get a standard square wrench, I find that a square bolt train wrench will do

 

An eight point socket is intended for use on those.


Image source: Billings and Spencer

 

I failed to mention I was really hoping to be able to drive these with a socket, not manually turn by turn with an open end or crescent wrench.

 

Good to know. I think I have some of those around, and if not at least I know now that's what's needed. Thanks ray2047!

 

When you buy a set of sockets.....you'll sometimes see two of the 8 point sockets at the low end. Snap On sets all came like that. I have 8 point sockets in all three drive sizes.

 

Hardware guys who've never seen a square-head lag bolt?

 

Yeah, I'm thinking that a hardware guy who has never seen a square head lag bolt should probably be working at one of the big box's instead. I can't recall for sure, but would almost be willing to bet that 30-40 years ago, before certain power tools became prevalent, it was the other way around; you only found square head ones. Today, I have ocassionally had to dig a bit deeper or search a bit farther to find the right size square head lag for the sake of maintaining an element of authenticity. Nevertheless, the guy should have known. I dont know how many lags you have to drive, but you may spend more time and as much money buying the right sockets as you would to simply buy new hex head bolts. Hal, thank you for the reminder. I have a wrench very much like that in one of my tool boxes, and have used an open end or adjustable wrenches on square head lags for so long that I may have forgotten what it was originally used for.

 

Not sure if he said he'd never seen a square-head lag bolt or if he said (after I asked) he'd never seen a socket to drive one. It was one or the other.

 

I don't have to drive many very often. Not necessarily planning on buying the right sockets (eight point [thanks again ray2047 for that info]) and have been simply buying new hex head bolts when I've needed lag bolts. But we do happen to have a bunch of old ones as I mentioned and I was curious about them, considering trying to use them if I can.

 

I have driven square head bolts with a 12 point socket many times. Fit is a little sloppy, sometimes a metric will give a better fit.

 

Okay, I did try fitting some of the square heads into 12 point socket but since the fit seemed sloppy I didn't actually try driving with it, just assumed it would slip/strip. But if you say you've had some success I'll at least give it a try. thanks

 

I wonder of one of those multi fit sockets would work? GATOR-GRIP Universal Socket | The Official AsSeenOnTV.com™ Shop

I wouldn't pay $20 but I think I've seen them much cheaper.

 

Near the bottom of the ad it says square nuts.

 

That got me thinking/wondering about this Crescent brand adjustable socket wrench tool that I never have really had occasion to use. Looks like just the ticket, at least for those square heads up to 1/2" square.