Blind Holes Countersink Dowel Drills / Countersink Boring Bits

Need a dowel seat and its countersink cut without a second tool on the spindle? The STE-BH70 is one step drill that does both: a 4 mm or 5 mm pilot stepping out to an 8 mm or 10 mm countersink, step length 10–30 mm, 70 mm overall, one 10 mm shank for all 11 size combinations. The step depth is ground into the tool, so the countersink repeats without a depth stop. Left hand orange, right hand black, tungsten steel body, custom steps from 50 pcs.

A dowel joint takes two tools, and they rarely agree: the seat bored on one head, the countersink cut on a second, and a rim that tears where the two axes miss. Every miss is a panel that will not close up. The STE-BH70 removes the second tool from the cycle.

It is a step dowel drill with the countersink ground into the same body: a 4 mm or 5 mm pilot that steps out to an 8 mm or 10 mm countersink over a step length of 10 mm to 30 mm. Because the step belongs to the tool, the countersink stops where the shoulder meets the board — no depth stop to drift, no second spindle to set.

Overall length is 70 mm on every size and every size shares the same 10 mm shank, so one collet covers the drawer. Left hand bits are orange, right hand bits are black, and both rotations are available across all 11 pilot-and-countersink combinations.

Use is wood drilling on woodworking and CNC drilling heads: dowel seats, shelf pins and blind pockets that have to carry a screw head. Each bit ships in its own plastic tube inside an export carton sized to the order, and non-standard step dimensions are made to your artwork from 50 pcs.

A countersunk dowel hole is decided by two things: how deep the step sits and how true the two diameters run to each other. These These are what hold both:

• Countersink ground into the body — pilot and countersink share one axis, so the 8/10 mm seat cannot sit off centre of its 4/5 mm hole.
• Fixed step length — 10–30 mm of step ground in, so every hole bottoms out at the same depth.
• Tungsten steel body — the wear face is tungsten steel, which holds the step shoulder to size through a batch.
• Sharp blade — the countersink edge shears, so a faced or veneered rim stays clean at the hole edge.
• Strong perforation — the pilot enters on the mark and holds centre instead of walking on a jigged panel.
• Long service life — the step shoulder is the wear face that decides it.
• One shank, one length — every size runs 70 mm on the same 10 mm shank, so a size change is a bit swap.
• Colour-coded rotation — left hand orange, right hand black: the colour is the check before the bit meets the chuck.
• Tube, then carton — one bit per plastic tube in a carton sized to the order, so edges arrive unchipped.
• Custom step from 50 pcs — special diameters and step lengths to your artwork from 50 pcs.

The usual choice is a two-tool cycle on the head, or a two-step job at the bench with a drill plus a separate countersink. A stepped bit collapses both into one plunge:

• One plunge, not two setups. The 4/5 mm pilot and the 8/10 mm countersink cut on one axis, so a dowel seat is one operation, not two.
• A depth that repeats. Step length (10–30 mm) is ground in, so hole 500 and hole 5,000 take the same countersink depth.
• Rims that pass inspection. The countersink shears the surface instead of lifting it, so faced board does not go to the reject pile.
• No walking on the panel. The pilot holds the mark, so the bit does not drift on a jigged position — one hole, one place.
• A drawer that stays usable. 11 combinations on one 10 mm shank: a size change is a bit swap, not a collet change.
• Wrong-hand mistakes stop at the rack. Orange left, black right, so a mixed spindle head cannot be loaded backwards and cost a panel.
• Special bits without a container order. Custom diameters and step lengths from 50 pcs keep a machine-specific profile on the shelf.
• The edge arrives as it was ground. A plastic tube per bit in a sized carton keeps the countersink cushioned until it is in the head.

It drills a dowel seat and its countersink in one plunge. The pilot bores the inner hole, the step cuts the wider seat to a fixed depth, so a dowel and its screw head both sit below the surface in a single operation.

Yes. The countersink is ground into the same body as the pilot, so one spindle does both diameters on one axis — no second tool, no second pass, and no alignment between two heads.

11 combinations: pilot 4 mm with a 10 mm countersink in 15 / 20 / 25 mm step, pilot 5 mm with an 8 mm countersink in 10 / 15 / 20 / 25 / 30 mm step, and pilot 5 mm with a 10 mm countersink in 10 / 15 / 24 mm step. All are 70 mm overall.

It stops at the step length, 10 mm to 30 mm depending on the combination. That length is ground into the tool, so every hole in the batch bottoms out at the same depth.

Order by the direction your spindle drives. Left hand bits are orange, right hand bits are black, and both rotations are available in every combination, so the colour is the check before the bit goes in the chuck.

Yes if the head takes a 10 mm round shank. Overall length is 70 mm on every size, so a size change does not move the height setting.

Yes, from 50 pcs. Send the artwork with the pilot diameter, countersink diameter and step length you need; the drawing is what keeps a custom bit on spec through the run.

Each bit goes in its own plastic tube, then a standard export carton sized to the quantity you order. Shipping is to be negotiated — your appointed forwarder or express, or a method we arrange.