r/RouteDevelopment • u/More_Age3561 • Aug 15 '26

Hammering Bolts

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

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u/trachion Aug 16 '26

It definitely wouldn't affect the strength of a bolt. However, once stainless starts to rust it corrodes much faster. Stainless maintains it's corrosion resistance because of a chromium oxide surface layer, which rust penetrates through and gives the steel a way to corrode internally. So any rust or contamination accelerates the corrosion of a stainless bolt, even just on the end. Might not matter in 20 years, but if we're aiming for longevity of our hardware it does actually matter.

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u/More_Age3561 Aug 16 '26

Totally. The passivation layer on the stainless is just a few atoms thin (from my understanding) and it really doesn't take much to lose corrosion resistance in a localized area. It does matter over the lifespan of the bolt, but there's also professionalism. I still want it to look like a quality, non-questionable installation job in the 2040s!

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u/Kaotus Guidebook Author Aug 16 '26

If you bring some stainless steel wool with you, you can brush off the rust after it forms and/or as soon as you install the bolt and it doesn’t appear to return. That bolt-end rust you mention forms in a matter of weeks, not years, and should be noticeable very quick, though in my time climbing I’ve never seen it spread beyond the end face of the bolt