Drilling granite wall

:-)

I have three.

My Dad managed to get two coal mines to join up in the early 1970s with a reasonable amount of accuracy - out by 6m and all calculations done by hand underground.

You can use long guides welded to the U WITH THE PILOT DRILL ALREADY IN THEM to ensure they 'meet in the middle

As with a rifle, the longer the guide, the more accurate it is.

Its like everything - making up a jig or a template is scarcely worth it for a one off. But if you do it again and again...

This is such nonsense. You are simply theorising. You clearly have no practical experience.

Bill

Absolutely.

Bill

Long masonry bits are slightly flexible. No amount of rigidity outside the hole will prevent wondering in the hole. And wood wouldn't stand the friction for very long. Soon the hole in the wood would become enlarged. A tiny bit of play in the wood would put the end of the bit well off course.

Bill

But why mess about like that? To prevent shelling all you need to do is get someone to hold a board against the wall. I've done it hundreds if not thousands of times. Almost every satellite or aerial installation needs a hole drilling from the outside.

Bill

why feed this retard?

Long 10mm drill bits in SDS Max fitting are not that easy to find... (and be prepared to pay for them when you do!)

SDS max will get you more impact energy per blow, but the drilling action is fundamentally the same as SDS Plus. It comes into its own fast and drilling larger diameters.

If I were the OP and did not already own a SDS, I would buy one - even if it fails on this job, you still have a very useful and versatile tool. If you really need SDS Max, probably better to hire it, since I find very few opportunities to use mine[1] (and almost always for chiselling rather than drilling)

I have a few but these are large masonry drill bits. I haven't seen the same system for SDS bits.

In your dreams.

Better to drill from the cosmetically important side, but the final exit point will be a modest away from any measured position after the drill bit has found it's easier path through the wall. More than 10mm in a

However may times you say bullshit, it doesn't make your assertion true.

Bullshit

The bit is pretty stiff to rotate in my cheapie when in roto-stop. Such I don't get the problem you mention. I guess not all cheapies are all the same.

I would expect they have improved with time as well as older designs get replaced.

Probably wouldn't work for SDS.

Bill

You keep on about it. Let's see proof.

Bill

Yesterday I took delivery of a Titan SDS Plus monster beast thing, plus 450mm and 600mm long 10mm drill bits.

When the neighbours are at work, I shall raise hell.