Through Holes Dowel Drills With Countersink Woodworking Boring Bits

Need a hole that goes right through the panel and a countersink around it, without a second setup on the head? This bit cuts both at once: D1 4 mm or 5 mm bore, D2 8 mm or 10 mm seat, drilling depth L1 10-30 mm, overall length 70 mm, on a round 10 mm shank. Body is tungsten steel with a V-type edge, welded at low temperature. Colour shows rotation: orange left, black right. 11 sizes.

A shop drilling through-holes runs into the same three things: one setup to bore, a second to open the countersink, and a head idle while the right spare is found. Add a bit that will not go into the chuck already bolted down, and a two-minute job costs a shift. This drill removes all three.

It is a through hole dowel drill with the countersink built into the same body, for woodworking drilling machines and CNC machining centres. One entry cuts both: bore at D1 4 mm or 5 mm, countersink at D2 8 mm or 10 mm, drilling depth L1 from 10 mm to 30 mm, overall length 70 mm.

The body is tungsten steel turned from fine-grain round bar, and the point is joined by a low-temperature welding process, so the joint does not cook the grain underneath it. That hardened section carries the V-type edge, which holds its form as the point clears the far face.

Rotation is marked on the body: orange left-hand, black right-hand, both on a round 10 mm shank, so the bit that goes back on the head turns the right way. Each bit travels in its own plastic tube inside an export carton; custom geometry is quoted from 50 pcs against your artwork.

What the numbers on this bit do once it is in the head:

• One bit, two diameters. The bore and the countersink sit on the same body, so D1 4 mm or 5 mm and D2 8 mm or 10 mm come out of one entry, not two operations.
• Eleven sizes on one shank. Three D1/D2 pairings across the depth range give 11 sizes, all on the same 10 mm round shank.
• Tungsten steel body. Cut from fine-grain round bar, so the section taking the load is the same material as the edge.
• Low-temperature welded tip. A cool joint keeps the grain under the cutting point intact instead of annealing it before the first hole.
• V-type cutting edge. The V-form opens the seat as it descends and leaves a rim that is cut, not pressed.
• Through-hole geometry. The point clears the far face in one pass, and the panel does not crack at breakthrough.
• Engineered flutes. Chips leave the hole instead of being re-cut under the point, so less heat reaches the edge.
• Colour-coded rotation. Orange is left-hand and black is right-hand, so direction is readable before the bit is chucked.
• 70 mm reach. 70 mm overall on the L2 dimension reaches through standard panel builds with no extension between chuck and cut.

A shop drilling through-holes has two options: bore on one head and countersink on a second, or buy a special that will not fit the head already bolted down. This bit closes that gap.

• One setup instead of two. Bore and seat come off the same entry, so a hole costs one pass on the head instead of two operations and a second fixture.
• The wear lands on the tip. Tungsten steel takes the abrasion, so the money goes into a bit that gets replaced, not into panels that get re-cut.
• A rim that stays whole. The V-type edge cuts the countersink rather than pressing it, and the panel does not crack as the point breaks through.
• Direction you can see. Orange for left, black for right: a wrong-hand bit is spotted on the tool board, before it is chucked and scrapped through a panel.
• Spares that fit what you run. One 10 mm round shank across 11 sizes means the head is set once and only the diameter changes.
• Sizes past the chart. Custom geometry from 50 pcs against your artwork keeps a bespoke bore from turning into a tooling project.
• Packed for transit. A tube per bit and an export carton per order, so a spare arrives with an edge rather than a chipped point.

Yes. The bore and the countersink are cut by the same body in one entry: D1 4 mm or 5 mm goes through the panel, D2 8 mm or 10 mm opens the seat, and no second operation or second fixture is needed.

D1 is the bore that passes through the panel; D2 is the countersink around it. The chart pairs them as 4 mm / 10 mm, 5 mm / 8 mm and 5 mm / 10 mm, with drilling depth L1 from 10 mm to 30 mm on an overall 70 mm body.

Yes, if that head takes a 10 mm round shank. The shank is 10 mm (S) on every size in the chart, and both rotations are supplied, so the machine does not have to change.

Colour marks the rotation: orange is left-hand, black is right-hand. Running the wrong one turns the edge backwards, which scorches the hole and takes the V-type edge off in a single panel.

Yes. Custom sizes are made from MOQ 50 pcs, and you send artwork first so the bore, the seat and the depth land where you drew them.

It should not, on a sharp edge: the V-type edge cuts the rim and the flutes carry chips out, so the far face is opened rather than pushed, and precise cutting edges help prevent splintering.

Because the abrasion lands on a tungsten steel edge. The point is welded onto a fine-grain round bar at low temperature, so the grain under the tip stays intact while the edge works through abrasive board.

One bit per plastic tube, then an export carton sized to the quantity ordered. Customized carton design is accepted, and lengths other than 70 mm are made to order.