1/4" or 8mm bolts for alpine climbing/emergency use

I'm prepared to get flamed for asking this but interested to hear inputs and start a conversation. 

I recently listened to a podcast with Vince Anderson and Josh Wharton where they mentioned that they were free climbing on old 8mm bolts on their new free route on Jirishanca. I also spent some time climbing in the Canadian rockies this summer and got to experience how tricky it can be finding pro/anchors in the limestone there. While climbing on mount temple my partner and I encountered an entire pitch of left gear and two anchors with new 3/8" bolts obviously drilled by some sort of rescue team about 3,000 feet up the face. I also have been getting more into rope soloing and have found it can be tricky to find multidirectional anchor pieces at times. All these things got me thinking about this. 

1/4" and 8mm bolts are not as strong and do not have as long as a lifespan as modern 3/8" and larger bolts but I know that they used to be the standard and were used frequently in the U.S. and Europe.

I have been interested adding a light bolt kit to my "bag-of-tricks for alpine climbing". (drill bit with a bunch of tape for a grip and 2-6 bolts+hangars) I also think this is lighter than an equal number of LA's. Obviously these would be used extremely sparingly and never on classic routes. I'm thinking like obscure limestone (since there is typically more gear on granite routes) choss-piles or life threatening situations. 

Some potential uses: 

Free soloing and end up over your head and either need to self belay section or rappel.

Can't find a multidirectional anchor for rope soloing/back loop soloing.

Partner gets hit by a rock and can't down climb and need to bail but can't afford to equalize 3 shitty pieces at every anchor to get down.

Lost/cliffed out on descent at night and need to drill single(?) bolt to rap off.

Questions I have:

How much strength are you losing between 3/8", 8mm, and 1/4" bolts?

How much time and energy do you save drilling 3/8" vs 8mm vs 1/4" bolts (i intend to test this as well)?

How bomber are 1/4"/8mm bolts, if the situation called for it, would you rap off a single 1/4" bolt?

What is the approximate "safe" lifespan of stainless bolts in limestone, granite?

What is the most bomber brand/type of 1/4" and 8mm bolt and hangar?

The standard 1/4" and 5/16" bolts in the U.S. (6mm and 8mm) were buttonhead compression bolts. They are NOT a good choice for limestone - they tend to fracture limestone badly during installation. The 5/16" buttonheads have not been available for many years. Fixe made a 8mm version of them in the 2000's but they were soft metal and I don't know what the strength was - they dented badly on installation and were easily broken off. None of these bolts were stainless.

The 1/4" versions are still made, and some use them for new routes on granite - they are a great temporary bolt in hard granite. But they are known to occasionally snap off after a single winter - that happened to me on a new route one time (about 9 months after placing it, over a single winter). I would not rap off a single 1/4" buttonhead even if I had just placed it.

Not sure if there is any stainless 8mm/5/16" bolt that is stainless and reasonably strong. Might be, haven't looked into it.

Time savings really depends on the rock, your drill bits, and your experience with hand drilling.

Greg Barnes wrote:

The standard 1/4" and 5/16" bolts in the U.S. (6mm and 8mm) were buttonhead compression bolts. They are NOT a good choice for limestone - they tend to fracture limestone badly during installation. The 5/16" buttonheads have not been available for many years. Fixe made a 8mm version of them in the 2000's but they were soft metal and I don't know what the strength was - they dented badly on installation and were easily broken off. None of these bolts were stainless.

The 1/4" versions are still made, and some use them for new routes on granite - they are a great temporary bolt in hard granite. But they are known to occasionally snap off after a single winter - that happened to me on a new route one time (about 9 months after placing it, over a single winter). I would not rap off a single 1/4" buttonhead even if I had just placed it.

Not sure if there is any stainless 8mm/5/16" bolt that is stainless and reasonably strong. Might be, haven't looked into it.

Time savings really depends on the rock, your drill bits, and your experience with hand drilling.

Thank you, very helpful!

Relevant thread:

https://www.mountainproject.com/forum/topic/121881022/8mm-bolts

stainless 8mm wedge bolt: https://www.oliunid.com/equipment/bolting-equipment/expansion-bolts/bolting-perforation-bolts/stainless-steel-bolts/raumer-hang-fix-inox-m8c-expanding-anchor-bolt-o8x60-mm.html

Are 5/16" bolts considered equal to 8mm from a drill bit to bolt size compatibility perspective? 8mm=0.3150 in.,  5/16"=0.3123 in.

Im sorry if this sounds critical, as Im genuinely trying to make helpful suggestions.  It seems to me though that your potential uses can all be avoided with better decision making.  I know drilling bolts is cool but knowing your limits and making good decisions is also cool.  If you really are questing out there in the Gnar Gnar, or are otherwise way out on the risk curve and need to slam something in and go down, a small assortment of titanium pitons and a tiny hammer on a single biner is something you are much more likely to actually carry with you and in many situations is probably the better option anyway.  Forrest, Lowe and Pika all used to make a nut tool with a tiny hammer on one end for testing pitons, driving the occasional one, etc.  Find one of those and carry it with your pins when you dont have an ice tool with you.  

Mitchell Goldman wrote:

Im sorry if this sounds critical, as Im genuinely trying to make helpful suggestions.  It seems to me though that your potential uses can all be avoided with better decision making.  I know drilling bolts is cool but knowing your limits and making good decisions is also cool.  If you really are questing out there in the Gnar Gnar, or are otherwise way out on the risk curve and need to slam something in and go down, a small assortment of titanium pitons and a tiny hammer on a single biner is something you are much more likely to actually carry with you and in many situations is probably the better option anyway.  Forrest, Lowe and Pika all used to make a nut tool with a tiny hammer on one end for testing pitons, driving the occasional one, etc.  Find one of those and carry it with your pins when you dont have an ice tool with you.  

Totally agree with your points! One of the things I love about climbing is there is no structure or hierarchy and you can go out and have any sort of adventure you want/need.
For all my imagined uses of this lightweight bolt kit I would already be carrying pins and an ice tool or a light hammer (Grivel Thor). 

You want to free solo with a hammer and bolt kit?

Desert Rock Sports wrote:

You want to free solo with a hammer and bolt kit?

Yee haw

Agreed the 1/4” are fine in granite but not at all familiar with limestone.  In general those 8mm Raumers look like the bomb for alpine hand drilling if you can get your hands on them.

with practice there’s surprisingly little difference in the time it takes to drill a 3/8 vs 1/4 hole.  5/16-8mm even less so.  I’ve theorized is has something to do with the rigidity of a thicker bit.

The big hole in your plan that I see is a taped up drill bit as handle/holder.  I’ve got a tiny,short little holder at it’s terrible compared to a full size one.   Hand cramps, binding,  just really inefficient.   I think your idea woukd be even worse.  That said I have place bolts with it on lead and in remote canyons so it works.  Also used it to bail off a wall of choss where pins simply wouldn’t have worked.

While it goes unsaid it seems to me that bolts have become a fairly common part of the alpinist toolkit.  When I saw the 5.13 tagged to Jirishanca (sp) I sort of assumed bolts. And watching Meru it would be interesting to me to know how those fat bolted anchors got placed (brap brap?).

I'd use 3/8" by 2.25" concrete screws for that application.  They'll be easy to remove later, which you should do if you're using any button heads or <3/8" wedge bolts.

https://youtube.com/shorts/sEKOPXiIegA?feature=share