Dr. Piton... Rivets?

So Pete,

What type of hardware do you use for rivets and how long do you use? Any other info about rivet replacement would be nice too, tricks and tips.

Thanks Dr...

Zac

Hey buddy,

I will post up on this in a few days. I have some pretty cool photos of rivet replacement off of Wyoming Sheep Ranch that I can put here. We also need to get Greg Barnes of ASCA to chime in, too.

Cheers,
Pete

The accepted standard for rivet replacement in the Valley is to use a hangerless 1/4" split-shaft buttonhead - namely the standard bolt for decades of climbing. These bolts are known by various names, usually just "buttonheads", but they're currently sold as the Powers Drive bolt ( powers.com/product_03601.html ).

The shortest available is 1.25". The problem with these is that if they stick out far enough to get a rivet hanger over them, the split shaft is often not fully in the rock (especially if replacing slightly blown-out holes or if there's any cratering while placing). So the standard length for rivet replacement is 1.5". The best method (developed/standardized by Bryan Law) uses two washers (fairly thin ones) on a 1.5" - one to protect the rock surface, and one to protect the underside of the buttonhead from odd-shaped rivet hangers torquing out and wearing out the head of the bolt.

These are easily replaced in the future since 1/4" buttonheads nearly always pull clean using tuning forks (#3LAs with slots - ASCA mills these and sells them).

The one complaint on their use is from those who consider them as too strong to be considered rivets (especially old-school folks who used 1/4" buttonheads on new routes for years). However, all the alternate rivets break, wear out, or shear off, often in ways that require a new hole. Some argue that a combination of bat hook holes and buttonheads can be used to keep things spicy and allow replacement of rivets in the same hole.

Thanks, Greg. That was fast.

Greg's links are busted. Here are the two correct ones:

powers.com/product_03601.html

powers.com/pdfs/mechanical/…

I believe Greg is mistaken when he refers to these buttonhead rivets as "split shaft" - this does not appear on the specs, nor does it look that way when you hold the thing in your hand. I have removed many old 1/4" split-shaft buttonhead "bolts" from El Cap, drilled out the holes, and put in a new 3/8" stainless steel expansion bolt. Those split shaft things are total junk, and it is scary how easily some of them come out.

In the future when it comes time to replace these ASCA buttunheads, will you be able to re-use the same hole? When I take out old "rivets" from El Cap - usually 5/16" diameter Grade 5 machine bolts hammered into a 1/4" hole and held in place by the "squishing" of the threads - I cannot re-use the same hole. I have had to drill a new 1/4" hole to put the new 1/4" buttonhead into, and have then patched the old hole with epoxy to render it virtually invisible.

One problem Greg points out is that if you replace an old "rivet" [machine bolt] with a new buttonhead, it makes the placement much stronger, and thus makes the route "easier" and/or "safer" since the rivet is far more likely to hold a fall. I believe Greg said on another forum that these buttonheads are good for about 2000 lbs on granite - is that correct, Greg? The specs only talk about their strength in concrete, which isn't all that strong.

Quick response only because it's winter and I'm at my girlfriend's place!

The shaft is split - just look at the picture on the link. That's how they work. And it's also why they don't work in softer rocks - the split shaft doesn't compress, it just carves its way into the rock.

When placed properly, they're pretty darn bomber - 2090 lbs ultimate load in shear (divide in 4 for safe working load...).

However, especially in places where they are subject to frequent freeze/thaw cycles, they pop easily after a decade or two. They rust and weaken and snap sooner or later. Hence the whole point of the ASCA - replacing old bolts, but primarily the 1/4" Rawl Drives that were the mainstay of bolting in the US from the late '60s through the late '80s.

They are easily replaced in the same hole, unless the rock is really poor. Another bonus of Bryan's two-washer system is allowing easier removal of the bolt in the future.

And you can probably reuse a number of the 1/4" rivet holes for the 5/16" machine heads (assuming the whole machine head comes out) by drilling the hole deeper and using a 1.5" Drive - even if the top section of the hole is flared/cratered, the machine head holes are usually shallow and the longer 1/4" Drive will be OK (not as bomber as freshly drilled, but stronger than most rivets).

In some cases where the FA party wants to maintain really scary rivets, other options may be available - for instance, the Wings of Steel dudes used Zmacs (ultra dicey, super soft - 6 of them are used to hold up the toilet paper in those standard NPS/USFS/BLM concrete outhouses), and these days you can get Zmacs with somewhat threaded, unscrewable nails.

Well I'll be buggered. I really was not aware that the shaft was split on those things! I thought it was held in place solely by the compression of the little "wings" on the shaft.

When Tom and I replaced anchors on the first two pitches of Wings of Steel, we consulted Mark Smith and Richard Jensen, and they asked us to replace their old Zed-macs with new ones of the same kind. It's like a little mushroom with a hollow shaft like a soda straw, and you pound a little nail into it. "We never intended them to actually hold falls," they told us. [Those guys are sick!]

I believe the box said that they would hold a whopping 485 pounds or so in concrete - sheesh. Pretty scary if you ask me - not even as strong as a head.

I am unfamiliar with the washer method, Greg - you had best explain that to me in greater detail along with some photos. We need to talk about this spring anyway - it is most probable that Minnesota Mawk and I will climb Wall of Early Morning Light, and we will have to replace some Beyer-ized anchors. So I will probably need a big supply of ASCA gear, please. I really need one of your #3 LA tuning forks - I have been using the ones Tom made from Bugaboos, and they are getting rather buggered. I would also use two #6 LA's side by side, but when I borrowed Erik's #3 LA tuning fork, it worked really well, although the angle is a bit aggressive for some of the more stubborn bolts.

It is possible if not probable that Beyer chopped some of Warren Harding's original dowels, which if I recall correctly from 1998 when I followed them for a ways on Reticent Wall, these consist of aluminum bar stock whacked into a hole, with the head kind of mushroomed. So we need to figure out what to do there. The dowels were not even three feet apart.