UKC

Hi folks. I need some advice on bolting granite.

Before I go any further - it's not for climbing purposes. It's on private land. It's not going to ruin any trad route (climbed or unclimbed). Basically it's low down on a short bit of bare, broken, quite loose granite. No real potential for climbing or bouldering etc. as far as I can see.

Hopefully headed off any outcry. So - I've never placed a bolt. What kit do I need and where can I buy/hire? I can find the bolts/hangars/resin etc. But what kind of drill do I need for granite? And any advice on drill bits?

Thanks all

In reply to Pbob:

Bolting on granite follows the same principles as bolting on any rock. If anything, good, solid granite is an ideal medium for bolts as (away from the obvious cracks) it is generally very solid resulting in strong placements. But checking the rock's integrity is always task #1. Visually assessing the surrounding rock along with tapping with a hammer tells an experienced route setter a great deal.

You need an SDS drill. If the location is remote from power supply then you'll need a cordless model. Contrary to popular belief you don't need a big, heavy rig. An 18V 1/2" chuck drill from a reputable brand will do the job. But be sure to distinguish between SDS and a 'hammer-drill'. You need SDS.

You'll need bolts obviously and a drill bit (SDS) of the diameter of the bolts (typically 3/8" diameter) and 3 inch in length or longer is best for climbing applications - but more than 3 3/4" is getting overkill in granite. Get a bulb blower to clean out dust and ideally a small bottle brush. There are special brushes available for bolting. Your kit will require a hammer to drive in the bolts and a spanner to tighten. A 3/8" nut requires a 9/16" spanner.

If you only have a few bolts to place you could get a hand-drill. Theses are fine for one or two holes but it can take 30-40 minutes per hole so it's a poor substitute for a power drill.

You mention resin which is usually to do with glue-in bolts. That's another type and one I haven't used myself so I'll leave it to others to comment. For wedge (Hilti) bolts I wouldn't use epoxy, it's just as likely to trap in moisture as keep it out. If you are in a marine environment and these bolts are for personal protection like climbing, you'll need marine grade steel or titanium bolts and hangers. Regardless of the environment avoid mixing metal types. Stick with stainless steel and they will last several decades.

In reply to Wild Isle:

Fantastic. Just what I needed. Thanks.

In reply to Wild Isle:

Plenty of good advice in there, although the quaint Imperial measurements might be misleading when sourcing equipment in Europe. Bolt diameters of 10mm and 12mm are both still very common, with 12mm steadily becoming the new norm, while length will typically be around 80mm for good quality limestone and any rocks that aren't softer than that.

In reply to Pbob:

Go read the general info on the boltproducts webpage then buy some of their stuff.
As Wild Isle said, you NEED to use an SDS drill as granite is simply too hard for a normal consumer hammer drill to drill holes of the diameter you need. If you live in a granite area then borrow a drill from a tradesman or rent one.

In reply to Toerag:


Ummn... SDS (or rather nowadays SDS+ or SDS Maxi) are mount types. What the OP wants s a proper pneumatic action impact drill (not the cheapo hammer drill). That being said, most proper pneumatic impact hammer drills do indeed come with SDS+ mounts for bits.

Unless you have a lot of bolting & big renovations to do... perhaps renting one will be more adviced (good enough such cordless drills retail four like 300 eur and up).

For glue ins, 12mm is the norm, and a proper blower, brush and 2 component epoxy. We mostly use Hilti stuff here , but I'm sure there are other suitable stuff available. For reference, the stuff we use with the bolts is HIT-HY-200-A, but you'll need a special 2 piston extruder for that stuff (again, from Hilti, other glue-system might be available).

In reply to HeMa:


What constitutes a pneumatic action impact drill? Give an example.

In reply to Pbob:

In reply to Deadeye:


I once put bolts in two granite boulders either side of a gate entrance so a chain could be put across the drive so who knows?

In reply to Toerag:

E.g. Makita DHR 242 or the 243 (which I have).

Not a proper one would be Makita HP 2050.

In reply to Deadeye:

A mate is exploring ideas for what to do with a small outcrop behind his house. Like I say not good enough to make a decent climb but there are bits which appear solid enough to attach something to.