Fixing an angled expansion anchor (wedge bolt) that wasn't drilled perpendicular

I came across an anchor bolt at the crag I'm developing at where the nut/washer wasn't sitting flush against the hanger due to the wedge bolt not being drilled perpendicular enough. I'm just simply sharing what I did to fix the problem. 

But I am also curious what other developers would have done, or have done before. 

Or would you have personally left the bolt as is? (Which I couldn't do because there are standards and expected competency/quality at this crag.)

Here are the before pictures:

I didn't feel just simply whacking on the threaded anchor body till it was straight was the best idea (given the less-than-perpendicular angle); My thoughts were that it would have driven too much of the upper threads against the top of the hole. So I decided to chisel away at the rock area under the hanger using my hammer and fine chisel. The goal was to match the hanger angle to that of the threaded anchor body sticking out. After doing so, I noticed I had a little extra play in upper of the hole, so I put the nut back on and lightly hammered the threaded shaft up about 1mm or so. Now the hanger sat really flush on the rock. Last, I re-tightened the nut to appropriate torque with my torque wrench, (I know what it was after finding out what type of wedge bolts the original installer used). The end result was pretty satisfactory.

In concrete construction I would specify beveled washers or re-drilling, if that's an option. Otherwise I'd have a discussion with the installer because that probably doesn't meet installation tolerance set by the manufacturer. 

I've used epoxy (JB Weld) under a hanger that wasn't flush to the rock.  Seemed to work ok.

Added bonus of your fix is that the hanger probably won't ever spin...!

Brian in SLC wrote:

Added bonus of your fix is that the hanger probably won't ever spin...!

^This. 

To the OP: Nice job! It's a good trick, not only for fixing crooked bolts, but also for spinners.

As an aside, if I suspect a bolt might be subjected to sideways pulls, possibly becoming a spinner, I'll sometimes drill this way on purpose: Ever so slightly crooked to increase friction on the bottom of the hanger. It can also be made a little better with a tiny bit of surfacing/trenching underneath. 

Looks like you fixed it Kevin, on harder rocks brush away your hammer marks before putting the hanger back on, you did a decent job of minimizing the flattening footprint based on the pix.

Not a fan of the JB weld on the hanger, more of a band-aid than a solution and color matching can be a pain.

I'm sure lots of developers do this flattening, but no one really likes to talk about chiseling away rock. 

I think in most instances this flattening method is better than drilling a new hole but best to be perpendicular in the first place. 

The more holes you drill the more tired you get and if you are drilling above your head or far from your center of gravity this will make misalignment more common. Orienting yourself into a better position to drill holes can help minimize this misalignment. You can also drill in a half inch or so, stop, check alignment then bias/correct for the remainder of the hole by gently favoring a side.

Looks good, thanks for the improvement!

Shawn S wrote:

Not a fan of the JB weld on the hanger, more of a band-aid than a solution and color matching can be a pain.

I'm sure lots of developers do this flattening, but no one really likes to talk about chiseling away rock. 

I think in most instances this flattening method is better than drilling a new hole but best to be perpendicular in the first place. 

Yeah...bit of an experiment.  The rock is quartzite, and the hanger was "tippy".  Hard to chisel it flat without additional fracturing...it seemed.

Over 16 years ago.  Still hanging in there as far as I know.

 Seemed like a bit of an improvement over:

Flatting the surface the best way to go I'd think.

Well as long as the hole can still breathe (water drainage is good, looks like yours can still drain out the bottom) and it don't look too bad then its not that bad of an option! Way better than that rusty old death triangle haha

I have used the drill to "countersink" hangers when doing bolt replacement on non-perpandicular bolt holes. Helpful to have a drill that doesn't hit super hard. 

Also something not mentioned you could extract the bolt and straighten out the hole for a larger glue-in.

I have done that to holes that were deliberately drilled at an angle for removable bolts. 

Brian in SLC wrote:

Yeah...bit of an experiment.  The rock is quartzite, and the hanger was "tippy".  Hard to chisel it flat without additional fracturing...it seemed.

Over 16 years ago.  Still hanging in there as far as I know.

good comment about the concern of quartzite wanting to fracture if you chisel/impact it. i am surprised the JB weld stuck to the quartzite so well, i usually find quartzite slippery as shit.  looks like a nice job.

If you're gonna mess with a wedge bolt, where the nut is not already loose, simply re-torquing it may not be enough to maintain the bolt tension. You should throw some loctite on it too. The bolt being at angle is not going to make it fail, but it may be more likely to loosen the nut, if the direction of pull facilitates that. If it isn't loose after significant use, leave it alone.  

Personally, I would have left it alone with some loctite. But in the case that it must be dealt with, I would have chopped or hammered in the stud, patched the hole and put in a new bolt. Less work and less visible damage to the rock.

On hard rock like granite, I use exclusively wedge bolts and overdrill the hole depth. Then in the case that a bolt needs to be removed, I simply hammer in the stud, and patch the hole with some glue mixed with rock sand. This has been the easiest method for a satisfactory cosmetic job in my experience.

I like the chalk to mark the area that's out of bounds, that's a good idea. I carry a spare cheapo bit for my rotary hammer for flattening the rock.

Nice job you did, it can be pretty fiddly work.

Fan Y wrote:

Personally, I would have left it alone with some loctite. But in the case that it must be dealt with, I would have chopped or hammered in the stud, patched the hole and put in a new bolt. Less work and less visible damage to the rock.

On hard rock like granite, I use exclusively wedge bolts and overdrill the hole depth. Then in the case that a bolt needs to be removed, I simply hammer in the stud, and patch the hole with some glue mixed with rock sand. This has been the easiest method for a satisfactory cosmetic job in my experience.

So the only reason to drill the hole deep enough to bury the bolt is because you are putting in garbage. Top quality SS wedge bolts will last indefinately in hard rock. Wedge bolts are very easy to spin and remove.

Put a bolt in that your friends grandkids wont have to worry about the first time. 

Shit happens in replacement but chopping and patching should be a last resort in my opinion.

timothy fisher wrote:

So the only reason to drill the hole deep enough to bury the bolt is because you are putting in garbage. Top quality SS wedge bolts will last indefinately in hard rock. Wedge bolts are very easy to spin and remove.

Put a bolt in that your friends grandkids wont have to worry about the first time. 

Shit happens in replacement but chopping and patching should be a last resort in my opinion.

Actually I use exclusively Petzl SS wedge bolts. Sometimes bolts need moving to facilitate better clipping stances, for example, simple as that. But hey, if you are a man who gets it right the first time with everything, good on ya!

timothy fisher wrote:

So the only reason to drill the hole deep enough to bury the bolt is because you are putting in garbage. Top quality SS wedge bolts will last indefinately in hard rock. Wedge bolts are very easy to spin and remove.

Put a bolt in that your friends grandkids wont have to worry about the first time. 

Shit happens in replacement but chopping and patching should be a last resort in my opinion.

If you have plenty of battery power, I see no reason not to overdrill holes. I always drill the full bit length when placing mechanical bolts. Even with SS wedge bolts, when they eventually need replaced there’s no downside to having that extra depth so that if removal doesn’t go well and the hole needs patched (which I agree should be a lower option than removing and reusing the hole) it can just be tapped in flush with the wall instead of requiring that the bolt be chopped or broken off first. If you’re hand drilling or battery power/weight is limited, there may be a case for drilling to exact depth.