{"id":3581,"date":"2017-06-13T08:00:05","date_gmt":"2017-06-12T23:00:05","guid":{"rendered":"https:\/\/norimen.net\/wordpress\/?p=3581"},"modified":"2026-05-17T06:50:57","modified_gmt":"2026-05-16T21:50:57","slug":"norimen-various-drilling-methods-3","status":"publish","type":"post","link":"https:\/\/norimen.net\/en\/norimen-various-drilling-methods-3\/","title":{"rendered":"Various Drilling Methods for Slope Drilling (Part 3)"},"content":{"rendered":"

Hello, everyone.<\/p>\n

This is Enta.<\/p>\n

I started overhauling the mixers a few days ago, and I\u2019ve successfully finished removing the rust from the first one lol<\/p>\n

Next, I'll thoroughly clean off the dirt and apply a rust-preventive coating.<\/p>\n

I use an airbrush to apply it, but that's a real pain, isn't it?<\/p>\n

That's hard!<\/p>\n

\"\"<\/p>\n

\n

But that's beside the point.<\/p>\n

Double Drilling (Double-Pipe Drilling)<\/strong><\/span><\/h3>\n

\u2014 Outer Casing \u2014<\/h4>\n

This is the drilling method used in rotary percussion drilling. (Applies to both skid-type and crawler-type rigs.)<\/p>\n

This is the outer casing.<\/p>\n

\"Outer<\/p>\n

As the name \"outer\" suggests, this is the outer casing used during drilling.<\/p>\n

The sizes increase in the following order: \u03c690 \u2192 115 \u2192 135 \u2192 165.<\/p>\n

This is what government agencies refer to as the nominal bore diameter.<\/p>\n

But!\u03c690 is the nominal diameter of the pipe; the actual circumference of the pipe is 96 millimeters.<\/span><\/strong>That's it.<\/p>\n

And the outer circumference of the bit is still large!<\/p>\n

Some of you might be thinking, \u201cHuh?\u201d But, for example, a drill bit with a \u03c690 bore diameter has an outer diameter of about 105 mm.<\/p>\n

There is a slight difference of a few millimeters depending on the manufacturer.<\/p>\n

For a drill hole diameter of \u03c6115, the length is approximately 125 mm.<\/p>\n

Basically, it means that a 90mm bit is a little too big to drill a hole large enough to fit a \u03c690 pipe.<\/p>\n

From a design perspective, this means it\u2019s erring on the side of safety. (This increases circumferential friction.)<\/p>\n

*The bit below is pretty worn down, lol*<\/p>\n

If you insert the inner casing into this, it will look like the image below.<\/p>\n

\"Double-Pipe<\/p>\n

And that completes the double-pipe drilling.<\/p>\n

Hammer<\/h3>\n

Since the hammers on the rotary percussion machine are mounted on the main body of the machine, they are classified as back hammers.<\/p>\n

While the down-the-hole hammer was a front-hitting hammer, the air hammer and percussion hammer are back-hitting hammers.<\/p>\n

\"Hammer\"<\/p>\n

There is a hammer built into the red part.<\/p>\n

In terms of power, the backhammer is less powerful than the down-the-hole hammer.<\/p>\n

 <\/p>\n

Double-Pipe Structure<\/h3>\n

\"Double-Pipe<\/p>\n

Water and air for drilling are supplied from the red circle.<\/p>\n

When drilling through the gap marked with the green circle, the slurry (drilling cuttings, etc.) rises upward.<\/p>\n

The slime is designed to be discharged to the outside through a part called the swivel.<\/p>\n

\"Double-Pipe<\/p>\n

That's a cross-sectional view from above, isn't it?<\/p>\n

This is a bit sloppy, but please cut me some slack lol<\/p>\n

This is double-pipe drilling (double drilling).<\/p>\n

I hope this gives you a general idea of what it's like.<\/span><\/strong><\/p>\n

There are plenty of other drilling methods besides these.<\/p>\n

I think these are typical examples of ground anchor installation and rebar insertion (rock bolts) work.<\/p>\n

As for other construction methods, there are various vested interests involved, so I can\u2019t discuss them publicly. I hope you understand lol.<\/p>\n

There are also ways to increase drilling speed that make you think, \u201cSeriously, this is impossible!!\u201d<\/p>\n

Since you can't see what you're doing, digging is a field that requires a high level of skill, so it's very difficult.<\/p>\n

I\u2019d like to try all sorts of things and keep developing my skills!<\/p>\n

Various Drilling Methods (Part 1)<\/a><\/span><\/span><\/strong><\/span><\/p>\n

Various Drilling Methods (Part 2)<\/a><\/span><\/span><\/strong><\/span><\/p>\n

See you later<\/p>\n

M's EDH3.5 Drifter Review | Key Evaluation Points in the Field<\/a><\/p><\/blockquote>\n