A drill bit that will go through metal, stone, tile and glass

[James Harris]

Is it feasible to have one drill bit that will work with all those materials?

There is a video at

From 0:48 the video shows a bit being used to drill through various materials including a brake disc and a tile, and apparently coming with a 10-year guarantee (though each replacement under warranty costs £5 including P+P).

This seems to be the product:

Are such drills feasible?

James

[newshound]

Cobalt drill bits are very good, but the advert reeks of snake oil. For an accurate hole in metal plate, you *don't* want to be grinding, you want to be cutting it.

I don't see why they wouldn't work on glass, personally I would stick with tungsten carbide tipped bits for tile and concrete.

The price of that package seems a bit too low to me. I wonder what "cobalt tipped" means? Proper "cobalt" drills are solid, not tipped.

[John Rumm]

The Bosch Multimaterial bits will certainly drill all those... They are very good on masonry, and adequate on other materials.

[David Lang]

Fine if lubricated with snake oil.

[newshound]

Certainly handy if you are drilling through a batten and want to mark the masonry clearly, but would *you* really use the same drills for everything? I would have thought that the cutting edge would blunt if used for serious stone or concrete drilling, especially with impact, and then not be much good for wood or metal.

What I liked about my set, before one of my youngsters filched them, was that they would tolerate more abuse when drilling metal than traditional high speed steel drills.

[David Lang]

Never tried one on glass - have you tried it?

IME they are OK on alluminium, never tried steel though.

[newshound]

For those with an interest in the metallurgy see

M2, M35, and M42 are different AISI grades of chrome/moly/vanadium high speed tool steels. M2 is the default for traditional good quality HSS drills, it looks as though M42 might be the norm for the "Cobalt" drills.

From

HIGH SPEED STEEL M2 high speed steel tool bits are designed for general purpose machining mild steel, alloys, and tool steels. They have good heat and abrasion resistant properties and are best used when making an interrupted cut or where the tool may be subjected to heavy load or shock.

5% COBALT (M35) (M35) 5% Cobalt tool bits are designed for heavy duty machining alloy steels and tough materials, such as castings and forgings. They have high heat and abrasion resistant properties and are best used when making heavy cuts, at high speeds and feeds, or where high heat is a factor.

(M42) 8% Cobalt tool bits are designed for machining work hardening alloys and other tough materials. They have increased water resistance and tool life. This improves performance and retention of the cutting edge.

8% COBALT (M42)

[newshound]

And for anyone who wants more about the metallurgy of cobalt in tool steels, this is very good:

[alan_m]

Bosch Multi-construction drill bits

concrete, masonry, brick, eternit, light building materials, multi-layer materials, ceramics and tiles, wood, plastic, sheet metals and aluminium.