Majosoft's Metalworking Site

Everything about Drilling

When you start to drill a hole in your product , you must make a start point. On my center page i describe how to do this. When you don’t do this, the drill will search and start always with drilling on the wrong position.

Two types of drills

There are many types of drills. We describe only metal drills.

There are two types of metal drills. For Short and long chips.

Long chips drills are for steel and short for brass.

Properly they look the same , but on the top of the dill we change the cutting surface like this.

Big Drills

When you must drill a big hole. For example a diameter of 30mm. You can do this with 1 drill, but it is for a lot of hobby people not wise to do this. It’s better to drill first a small hole and than the big one.
The reason is the thickness of the soul of the drill. This part of the drill do not carve very good.

It is possible to drill a big hole with 1 drill, but then you must grind the soul.

Turning Speed

Because there are 10000 different kinds of materials shall i show you the most used.
There a 2 things you must know.
1) Cutting speed.
2) Turning speed. ( for drilling machine )

With the cutting speed you can calculate the turning speed.
Example. You use normal steel. That has a cutting speed of 20. And you use a drill with a diameter of 6 mm.

Turning speed = ( Cutting speed X 1000 )  /   (  Diameter X PI )

Turning speed =  ( 20 X 1000) / ( 6 X 3.1416 )

Turning speed = 1061 rotations / minute

Material                     Cutter speed
Stainless Steel         6 - 10
Brass                         50 - 100
Copper                      25 - 35
Aluminum Hard         50 - 120
Aluminum Soft          30 - 50
Synthetic soft            50 - 100
Synthetic hard           15 - 35

The speeds i gave you are old. New types of drills have different and much higher cutting speeds, but these values what i gave you are for hobby people and not for industrial tools.

Grinding

I’m not ready with this site, be patience.