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Advice/Help pulling 3/8 inch stud bolts.


Original Post
climber pat · · Las Cruces NM · Joined Feb 2006 · Points: 241

I built a greggor stud puller and spinner but I am having problems using them, especially spinning a stud.  I think the problem with spinning the studs is that it the original installer did not drill the hole perpendicular to the rock.  I think the studs were bent inside the hole when the bolt was tightened down.  The initial problem is just getting the stud to spin.  I take off the bolt and hanger and tap the stud sorta gently with a hammer to push the stud into the hole.  Sometimes the stud moves with the tapping sometimes it does not, even if I hit it fairly hard.  I try the spinning tool but the drill is unable to spin the stud.  Then I try pulling the stud a little and then retap into the hole.  After a few rounds of this the stud usually will wiggle around a little bit.  But when I try spinning the stud usually jams again and the drill wants to wobble.  I have tried using a wrench, hangers, and bolts wedged between the stud puller and the rock to have the stud puller pull along the studs axis.

If I am able to get the stud to spin it usually wobble the drill so bad that it is really difficult to keep it spinning.  

I had success with one stud and that stud's hole was much closer to perpendicular to the rock than the others.  It spun pretty well and eventually came out.

I have tried 'lubricating' the stud with water and grid before starting.  That seems to help a little bit.

  

Drew Nevius · · Oklahoma · Joined Jun 2012 · Points: 1,884

I’ve only done a handful of wedge bolts, but I would try putting the coupler nut (to be used with the spinner tool) and try tapping the bolt with a hammer to straighten it out so it wobbles less when you spin. Definitely spray the hole before spinning, and every 10s or so after that. If the hole is too angled to pull the bolt without bending it, you may be able to just spin it and pull it as it widens the hole enough to come all the way out (occasionally moving it back and forth as you spin). Spinning it all the way out and widening the hole obviously only works assuming you’re replacing with 1/2” bolts.

Good luck with it!

eli poss · · Durango, Co · Joined May 2014 · Points: 523

Have you tried using the drill in hammer mode instead of tapping the bolt with the hammer? That ended up solving an issue that first gave me trouble when trying to spin it. Sometimes you just need a lot of lube and some force behind it it (the hammer drill) to get it started.

Another thing is that on one wedge bolt I pulled, I had to keep trying to spin it even though the drill was binding, and after like 5 sec it stopped binding and started spinning. You might just have to be a little bit more persistent with the drill, although of course don't break your drill. 

M Hanna · · Seattle, WA · Joined Apr 2015 · Points: 5

That's a good idea Eli, I always forget about hammer mode.... I have noticed this spinning thing is pretty hard on drills.

MH

climber pat · · Las Cruces NM · Joined Feb 2006 · Points: 241
eli poss wrote: Have you tried using the drill in hammer mode instead of tapping the bolt with the hammer? That ended up solving an issue that first gave me trouble when trying to spin it. Sometimes you just need a lot of lube and some force behind it it (the hammer drill) to get it started.

Another thing is that on one wedge bolt I pulled, I had to keep trying to spin it even though the drill was binding, and after like 5 sec it stopped binding and started spinning. You might just have to be a little bit more persistent with the drill, although of course don't break your drill. 

I have not tried hammer mode explicitly and not for a long duration. I tried spinning until I could smell the drill getting hot.

I will try again with the hammer mode, much more lubrication and persistence.

Thanks
M Hanna · · Seattle, WA · Joined Apr 2015 · Points: 5

An aside, but wondering if anyone has tried an abrasive powder slurry as the ridge cutter lubricant.... Seems like this would create the needed score of the wedge with less spinning needed. Lots of options too, cerium oxide, aluminum oxide.....

https://www.kramerindustriesonline.com/product/silicon-carbide-grit/

Just a nerdy thought

MH

eli poss · · Durango, Co · Joined May 2014 · Points: 523
climber pat wrote:

I have not tried hammer mode explicitly and not for a long duration. I tried spinning until I could smell the drill getting hot.

I will try again with the hammer mode, much more lubrication and persistence.

Thanks

Am I the only one giggling at this? Maybe I should go back to hiding under a rock...

Guideline #1: Don't be a jerk.

Fixed Hardware: Bolts & Anchors
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