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Thread: Broken Lag Bolts

  1. #1
    Join Date
    Jul 2016
    Location
    Greensboro, NC
    Posts
    127

    Broken Lag Bolts

    I am moving my DC from the floor to hanging on the wall. When I was installing the brackets 2 of the lag bolts just snapped in two, right where the threads start. The last 2, of course. They are 1/4-4" bolts and I drilled a pilot hole just about the size of the shaft (not counting the threads). So, now I have to move the whole operation either higher or lower, what a pain.

    I have never seen a lag bolt snap like that? I feel like maybe I shouldn't trust these bolts with a 200lb chunk of metal over my head. Anyone have any ideas why this happened and maybe what kind of bolts I need to use?

    Thanks,

    IMG_3620.jpg

  2. #2
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
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    12,298
    Going into what, pine studs? Were you having to crank pretty hard? (Almost looks like it from the head but hard to tell from a picture.) A slightly larger hole and some wax rubbed into the threads might eliminate the need for a lot of force from friction.

    I don't use 1/4" much here on the farm, I prefer 5/16 or 3/8" for almost everything, sometimes larger. They don't make hardware like they used to so I prefer larger.

    JKJ

    Quote Originally Posted by David Justice View Post
    I am moving my DC from the floor to hanging on the wall. When I was installing the brackets 2 of the lag bolts just snapped in two, right where the threads start. The last 2, of course. They are 1/4-4" bolts and I drilled a pilot hole just about the size of the shaft (not counting the threads). So, now I have to move the whole operation either higher or lower, what a pain.

    I have never seen a lag bolt snap like that? I feel like maybe I shouldn't trust these bolts with a 200lb chunk of metal over my head. Anyone have any ideas why this happened and maybe what kind of bolts I need to use?

    Thanks,

    IMG_3620.jpg

  3. #3
    Join Date
    Feb 2014
    Location
    Lake Gaston, Henrico, NC
    Posts
    9,075
    http://www.spax.us/en/power-lags.html#.WxX51kgvztQ

    I've never wrung one of these in two.

  4. #4
    Join Date
    Sep 2011
    Location
    Warwick, Rhode Island
    Posts
    347
    Double, triple ditto marks on Tom's reply. Box store lags bolts can't withstand the rotational force to drive them home even with a pilot hole and waxing the the lag. I switched to Spax and I have never snapped one of them. I use their #6.8.and 10 screws too now.

  5. #5
    Join Date
    Jul 2016
    Location
    Greensboro, NC
    Posts
    127
    Thanks everyone. Spax lag bolts it is! I'll be picking some up today.

  6. #6
    Join Date
    Jan 2008
    Location
    Western Nebraska
    Posts
    4,680
    I prefer the GRK RSS over the Spax, partly because I hate the store that sells Spax here, but also because I think they are better. Either is better than a cheap lag bolt though.

    https://www.grkfasteners.com/tech-data/specs/rss

  7. #7
    Join Date
    Feb 2003
    Location
    McKean, PA
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    15,649
    Blog Entries
    1
    That is a typical lag bolt failure and it can occur even after you have completed your assembly. Most lag bolts sold today are of lesser quality and should not be depended upon for wight bearing. I use the better grade Timber lok screws now instead of lag bolts.
    31Ip7kqaAnL._AC_US218_.jpg
    These are like grade five bolts for wood.
    Lee Schierer
    USNA '71
    Go Navy!

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

  8. #8
    Quote Originally Posted by Steve Rozmiarek View Post
    I prefer the GRK RSS over the Spax, partly because I hate the store that sells Spax here, but also because I think they are better. Either is better than a cheap lag bolt though.

    https://www.grkfasteners.com/tech-data/specs/rss
    Another vote for GRK RSS fasteners. HD sells them.

  9. #9
    I'm also a big fan of timber locks. They are rated as strong as a 1/2" lag bolt. I drove hundreds of them when I built a retaining wall out of 6*6 pt wood without one issue . You can get timber locks at lowes

  10. #10
    Join Date
    Jul 2016
    Location
    Greensboro, NC
    Posts
    127
    I already installed the 3 5/16 Spax lag screws per bracket. I'm 220lbs and can hang from them and they don't move at all. My DC motor is about 150lbs, so I think I'm probably good. I'm also going to have a 2x4 stud propped under it to help. Probably overkill, but better than it falling on my head.

    I looked at the technical specs and the Timber lock and Spax are about the same as far as weight bearing.

  11. #11
    Join Date
    Feb 2014
    Location
    Lake Gaston, Henrico, NC
    Posts
    9,075
    I use any of the goods ones mentioned so far, with the only preference going to the nearest seller when I need some.

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