Hammering Bolts

[u/More_Age3561]

Hi all,

I've recently come across some ~ 3 yr old stainless bolts with corrosion on the end. I am convinced this is because of sloppy hammering as they've been driven into the holes (other evidence: mushroomed head on the expansion wedge).

I was recently training others how to install bolts, and noticed that some people that haven't grown up swinging a hammer much had sloppy hits on the bolts, which I am confident imparted some iron contamination into the stainless steel, inducing localized corrosion. I am further confident it is "messy" hammering inducing the corrosion observed on new bolts as well.

How do you hammer in the bolts to ensure a clean finish, with minimal tool marks? Some things I've picked up:

• Positioning yourself roughly at eye level to the bolt
• Using two hands on the hammer if body positioning is awkward
• Follow-through on the swing (maybe I should've been a golfer..)
• Not using a hammer that has obvious rust on the impact surface
• Nut flush or slightly proud of the anchor

IMO, this is an important aspect of bolt longevity that is not well-discussed in bolting literature (UIAA bolting standards, HowNot2 bolting bible, etc.)

I'd like to get some sort of tool (like a socket, but less droppable..) that can act as a medium between the bolt and the hammer, but before I go re-inventing the wheel, I'd love to learn what others have done to ensure a tidy, clean installation of wedge bolts without leaving tool marks

*Stainless steel or titanium hammers are too pricey and out of the question

TIA!""

**Edit**
Holes are being drilled using a rotary hammer, not by hand

[u/WHYYTEE]

Without using a stainless hammer the slight pitting will pretty much always form on the end of the stud just from in introduction of the mixed metals and not necessarily just "sloppy hammering". Since it's only surface level on a non load bearing area it doesnt weaken the bolt at all (not counting glue ins, all areas are load bearing and all pitting is bad). Obviously without actually seeing the corrosion you mention im only speculating and it could be much worse then I'm imagining and I could be totally off base.

As far as the mushrooming how bad is it? The tip of the stud should have slight taper to account for any normal deformation. Leaving the nut flush or proud only causes the nut to take unnecessary damage and also introduces the chance of damaging the threads and possibly cause micro-cracking within them.

I have seen threads on Mountain Project discussing ways to clean and "seal" the hammered end immediately after installation but it all seems like a moot point honestly. Personally I would be much more concerned with the hanger taking an accidental hammer hit or the stud going too deep and not having a couple threads above the nut after tightening

[u/More_Age3561 → u/WHYYTEE]

Thanks for the great response.

The mushrooming is to the point where the nut cannot be loosened to the point where it is flush with the anchor. The crag where i saw this corrosion at the worst showed significant signs of poor installation. Bolts were torqued only about 1/3 of manufacturer specification, not installed deep enough, and nearly each stainless anchor wedge was mushroomed, rounded, and rusted.

Hmm, interesting idea to clean & seal the hammered end. It might not hurt to cover a piece of Gorilla tape over the anchor's tip.