Wedge bolts, clean vs uncleaned hole strength.

I was curious if anyone had data on strength for a wedge bolt with a blown out/bushed hole vs a hole that was not cleaned.    I know it is a big deal with glue ins, but couldn't see it being critical with a wedge.   I ask because I recently  set a 12mm wedge for a 2 bolt single pitch anchor and am not 100% sure I blew the hole out, and I know I forgot to brush it.    It took spec torque, near 40lbs, just fine and set appropriately deep as I had overdrilled. It seems solid and holds weight fine.  I will funk test it as well.   Just curious if there is any reason I should consider sinking it and  placing a new bolt or if it is nbd.  Thanks!

It´s fine and you need to do nothing, you´ve already tested it by torquing it up. The standard tightening torque for metric wedge bolts tests them to around 20kN (for whatever thread you have got on yours you can look up the compression force/torque tables on the internet). This is the reason for the tightening torque, to test the bolts installation and it is common to apply the test torque then use another lower value for whatever is being fastened.
The problem with too much dust in the hole is that it may get between the clip and the cone and prevent it sliding and locking up, since your´s torqued up o.k then it´s good to go.
I test about 100 wedge bolts per year (each time a new batch is delivered) and don´t bother to clean the holes properly, in fact I don´t even tighten them up, just hammer them into the hole and put them on the test rig.

Caveat that doesn't apply to most:

Hand drilling out in granite in wilderness/national parks we use short wedge anchors (2 1/4") that have a minimum embed of 1 7/8" and excessive rock dust left in the hole can lead to some slippage until they torque down leaving a small margin over the minimum embed depth. That said, a nice round hole matters even more and quality rock for the initial placement.  But, there is a perfect storm of all of the above that can lead to a crappy bolt so be aware.

Harumpfster Boondoggle wrote: Caveat that doesn't apply to most:

Hand drilling out in granite in wilderness/national parks we use short wedge anchors (2 1/4") that have a minimum embed of 1 7/8" and excessive rock dust left in the hole can lead to some slippage until they torque down leaving a small margin over the minimum embed depth. That said, a nice round hole matters even more and quality rock for the initial placement.  But, there is a perfect storm of all of the above that can lead to a crappy bolt so be aware.

Well yes but!!!!

Dust in the hole can certainly make them a bit "soft" to take up but the minimum embedded depth is only related to concrete, not the bolt. You need the depth to get a large enough cone of fracture for whatever material you are bolting in and in granite I have succesfully tested resin anchors down to 20mm embedded depth. In fact my local climbing wall uses drop-in inserts in extremely high quality concrete and they test out fine with only 25mm. The standard requires an embedded 5x the diameter for bolt-ins but in granite or other good rock (especially with 1/2" bolts) I can´t say I´d get too concerned about going a bit lower, I´ve installed hundreds myelf  

Thank you both for the info!  Harumpfs answer brought up another question in my mind.   Assuming his above scenario of the bolt have set above a depth you are comfortable with, what do you do with that bolt?  Can you back off the nut and bang it in deeper + retorque?  I assume there is some risk of a spinner if you damage the sleeve in the process.   

Taotao 1 wrote: Thank you both for the info!  Harumpfs answer brought up another question in my mind.   Assuming his above scenario of the bolt have set above a depth you are comfortable with, what do you do with that bolt?  Can you back off the nut and bang it in deeper + retorque?  I assume there is some risk of a spinner if you damage the sleeve in the process.   

Jim makes an excellent point that it really comes down to the rock quality.

Rarely we do come across some rotten granite that was previously under hummocks that seem to practically digest the rock but have to use it to protect some sections of routes. This  becomes a little sketchy if the bolt doesn't torque up right away, imo.

Point being that in ideal Granite (something like 20-50k PSI hardness) you can be remarkably shallow and not have any trouble with producing a "cone" of rock failure that occurs in softer stuff.

Jim knows way more about it than I do, but as I understand it most of the shear rating for bolts comes down to the crushing of the soft concrete (ie 3-5k PSI) below the bolt and it then pulls out. If your stone is very good this doesn't happen in any climbing scenario imaginable. The minimum embed depth is based on this soft concrete testing and only when we are obligated to place in bad stone does it become an issue for us.

This is my understanding anyways, hopefully Jim can provide us with a more educated elucidation.

DO NOT try and hammer the bolt in and try again. If it torques up well you have to decide to use it or not, or pull it and patch it and use another hole. For wedge anchors the 4-tipped type drills produce a better round hole and a non-round hole is probably the issue with bolts failing to torque up quickly.

It´s all a bit complicated and variable! Normally you can trust if the bolt takes the specified torque then it will hold the force given but if the rock isn´t continous then life gets difficult, the extreme being bolting in conglomerate where if the bolt is through a pebble then it has enough strength to hold the cone and provide the required torque. But the pebble pulls out! That´s why the standard specifies the distance apart for the tester support legs.
Shear strength and the way failure occurs is well studied for concrete but hardly at all for climbing anchors, we do the tests because the standard says we have to but that´s usually it because with the normal bolts and the test concrete the failure forces and the way they fail is more or less identical to testing straight out. Shear testing there is a bit of damage to the concrete and then the bolts fails in bending shear anyway. Industrial testing in concrete shows that normally one expects the fastening to fail either by material failure or pry failure (the fastener tilts and pries out a half-cone of concrete) but I´ve only ever seen material failure since I´ve never tested short enough bolts in soft enough rock. Normally we wouldn´t test a bolt this way because it would already have failed the straight pull-out test as the cone would just rip out through the block.
I´ve tested shorter bolts for various reasons but it´s not much of a priority to investigate the characteristics, first because the standards require adequate depth so the market is limited and I´m not sure I want to encourage the general public to reduce depths to the limit!