Countersink Drill Bits

[chiangrai]

Hi,

I just got these drill bits from Home-Pro.Vermont American.

They are excellent quality but I'm a little confused about how to use them.

There are 2 cutters at the top,I don't know what the first one is for.

I use non tapered screws,the bronze coloured ones for power drivers.

Can any any one tell me if I should go as far as the first or second countersink blade.

[bankruatsteve]

I've never used like that myself, but I think you would counter-sink to the size of the screw head you plan to use. Yah?

[chiangrai]

Yes,but what is the barrel shaped hole that it cuts out

before you get to the larger countersink blade.

I've never seen anything like it before and it was the only countersink

bit in homepro.

I can use it o.k but I would love to know what it's for.

[ClutchClark]

You only use the first "most outward" tip of the actual countersink (the dark part). You set the pilot hole depth based on the length screw you are using. Then drill into the wood until you have just penetrated with the counter-sink blades maybe 1mm (depending on application). Are you going to be plugging the fastener head from view when you are finished? Perhaps with a wood dowel?

Not knowing your application it is difficult to offer more specific instructions.

[chiangrai]

O.k,I see.

I'm only sinking the screws so as to be flush with the wood.

But if I was sinking them further I would cut out the barrel shaped

hole so I could add filler later,is that about the jist of it.

Anyway the most important question is answered,just barely make an indentation

with the first blade if I'm only countersinking to be flush with the wood.

[ClutchClark]

O.k,I see.

I'm only sinking the screws so as to be flush with the wood.

But if I was sinking them further I would cut out the barrel shaped

hole so I could add filler later,is that about the jist of it.

Anyway the most important question is answered,just barely make an indentation

with the first blade if I'm only countersinking to be flush with the wood.

If you only want the fastener, or screwhead to be flush with the wood surface then the countersink should barely penetrate that surface. Your goal is for the sharp countersink blades to just cut the fibers in a clean fashion. So much depends on the type of wood and moisture content as well.

Best to apply downward pressure between the two pieces being screwed together either with clamps or if its a deck, then with body weight.

As you know, its important to spin the screws at a steady slow-to-medium speed or the heads will either snap off or go in too deep.

I wish I had a good woodworking project right now--I envy you. Need a helper? ;-)

[wayned]

It's used to drill the hole for a counter sunk screw and the hole for a plug ate the same time:

[chiangrai]

Yes,

The drill bit drills the pilot hole.

The first countersink blade drills the countersink space for the screw.

I get that much and it's all I need to know for what I'm doing.

But what is the second blade that drills a larger hole for,and the third blade which drills an even larger hole.........what's that for.

Something to do with plugs and dowels,I suppose.

[wayned]

Try this, specialized for furniture and special fasteners:

[thaibeachlovers]

The drill is for the part of the screw in the wood being screwed into, the second part is bigger so the hole in the wood being attached to the first piece of wood is larger than the screw thread, and the final, bevelled, part is the actual countersink. As shown in the middle picture in # 9.

You go to the second cutter, which is the countersink.

Saves having to change bits 3 times.