Bolting Question: 3/8 vs 1/2 inch

I am generally placing 3/8in 304 s/s wedge bolts in andesite, 1/2 inch in roofs.

I read in the Vertical Times (Access Funds magazine) that they recommend using 1/2 inch hardware for all placements because they are easier to replace. Can any one enlighten me on why this is?

I assume it is because 3/8 inch hardware is more likely to break and get stuck in the hole when removing it. How big of a problem is this for s/s hardware?

In order to preempt bolts breaking during removal in the far off future I have been drilling all of my holes to a full six inches. That way if the bolt breaks the piece remaining can be pounded down into the bottom of the hole and the hole can be reused. Does that seem like a reasonable solution?

Thanks

A number of people have been developing tools for removing bolts and specifically wedge bolts. The key to most of the tools for wedge bolts is the ability to remove the nut and hanger and then being able to thread on some sort of spinning then pulling tool.

So, there is not really a problem with using 3/8" wedge bolts as long as you take care to not damage the threads when placing them.

That being said, the longevity of a 1/2" SS bolt is probably longer than a 3/8" bolt, especially if the rock is on the soft side and the bolt gets fallen on a lot.

A quality stainless bolt in most environments should last 50+ years and by the time someone has to replace it I am sure a mass-produced climbing-specific bolt remover will be available. We already have tools that can remove 3/8" stud bolts with a reasonable amount of success and the tools are improving yearly. What it sounds like you're doing currently is fine. Place a quality 3/8" stainless wedge like the Hilti Kwik 3 and a stainless hanger and you'll be fine.

It's not just cost, but number of holes per battery. Obviously a 1/2 hole is going to take more power to drill than a 3/8. I botched a stud bolt a while back and was able to pull it back out enough to break it cleanly with a hammer hitting it back and forth and then pounded in the remainder flush. The collar got jammed on the edge of the hole going in.

In hard rock, 1/2" bolts seem like overkill. I don't understand how a 1/2 would be easier to remove than a 3/8. Seems to me it'd be easier to replace a 3/8 with a 1/2 by reusing the same hole and drilling it to 1/2.

Stich - if you can drill the hole deeper than needed, you can just countersink the whole bolt if you end up with a bad placement. It doesn't take much drill power or time to get that extra 1/4" or so of depth. Just a friendly suggestion.

RadDawg wrote:In hard rock, 1/2" bolts seem like overkill. I don't understand how a 1/2 would be easier to remove than a 3/8. Seems to me it'd be easier to replace a 3/8 with a 1/2 by reusing the same hole and drilling it to 1/2. Stich - if you can drill the hole deeper than needed, you can just countersink the whole bolt if you end up with a bad placement. It doesn't take much drill power or time to get that extra 1/4" or so of depth. Just a friendly suggestion.

RadDawg wrote:Stich - if you can drill the hole deeper than needed, you can just countersink the whole bolt if you end up with a bad placement. It doesn't take much drill power or time to get that extra 1/4" or so of depth. Just a friendly suggestion.