How to choose multi-material drill bits: diameter, shank and use

A multi-material drill bit is the right one when you need to drill different materials with the same drill, masonry included, without changing the bit for every hole. For small and medium holes, between 3 and 8 mm like those in this collection, a hammer drill or a driver compatible with the bit's shank is enough. For frequent holes in concrete or large diameters, it is better to move to SDS plus or SDS max bits with a rotary hammer.

The types

• Single multi-material bit: the best seller in the collection, with a carbide tip designed to go from one material to another. You will find them in diameters from 3 to 8 mm and above, with a working length of about 7 to 13 cm.
• Drill bit sets: the number in the name indicates the pieces (sets of 9, 10, 19, 63, 85 or 100). They are worthwhile if you work with different sizes and want everything in one case.
• Drill and screwdriving sets: combine drill bits and screwdriving inserts, useful for the installer who does both operations.
• Hex-shank bits: fit drivers and drills that accept the quarter-inch hex, such as those on compact cordless models.
• Water dispensers and drilling guides: accessories to cool the bit or guide the hole, when precision is needed or when drilling a material that heats up a lot.

How to choose according to the job

The features to look at

• Diameter: from 3 to 8 mm in the most common values in the collection, including intermediate sizes such as 3.5 and 6.5 mm. It must match the wall plug or screw: a hole that is too large and the plug will not hold, too small and the wall breaks.
• Working length: from 73 to 130 mm. This is the usable depth of the hole, not the overall length. If you have to go through a thick element, choose the longest one.
• Tip type: carbide, to withstand hard material. A carbide tip does not make the bit suitable for every material: always look at the stated application material.
• Chuck fitting: cylindrical, hex, SDS plus or SDS max. It must match your tool.
• Application material: the collection lists multi-material and masonry. A bit marked for masonry only is not suitable for metal.
• Weight: from a few grams up to about 165 g for the sets. Useful only if you carry many sets around.

Common mistakes

• Engaging hammer action on metal, timber or tiles: the bit is ruined and the tile breaks.
• Choosing the diameter from the tip of the wall plug without checking the plug's data sheet.
• Using a multi-material bit on reinforced concrete for dozens of holes: it wears out immediately.
• Forcing it instead of letting the bit do the work, or not withdrawing it now and then to clear the dust.
• Carrying on with a worn bit: it drills badly, heats up and makes you push harder.

Frequently asked questions

Is a multi-material bit suitable for concrete?

For a few small holes, yes, with a hammer drill. For continuous work in concrete, SDS bits and a rotary hammer are better.

Can I use it with a cordless driver?

If the bit has a hex shank, yes, but for masonry you need a tool with hammer action or enough power. For timber and soft materials it is fine.

When do I engage hammer action?

Only on masonry and concrete. On metal, timber and tiles it must be switched off.

Is a single bit or a set better?

A set if you change size often; a single bit if you have a fixed diameter and use up many, for example for a standard wall plug.

You will find all the bits in the multi-material drilling accessories collection, such as the DeWalt DT6525-QZ multi-material drill bit or its siblings DT6515-QZ and DT6516-QZ. For advice on diameter or shank, ask for a quote from the AMES technicians.