70mm Four Flutes Drill Bit Boring Hole For Woodworking Drilling Machine

Need one bit that opens a clean blind hole for a concealed hinge, in board or solid timber, on a head turning either way? The PRO-HI70 does it: four flutes, a tungsten steel alloy head, 70 mm overall length with 57 mm also stocked, and 30 diameters from 12 mm to 80 mm on shanks of 10 mm to 25 mm. Right hand is black, left hand orange, each bit in its own plastic tube, 50 to a carton. The bit cuts blockboard, melamine faced board, chipboard, plywood and MDF.

Fitting concealed hinges all week brings the same three problems: a bit that lifts the melamine and leaves a pale ring round the cup, chips that pack the flutes on MDF until the feed stalls, and a left-hand spindle idle because only the right-hand direction was ordered. The PRO-HI70 removes all three.

It is a 70 mm four flute hinge boring drill bit — a carbide hinge drill bit with a tungsten steel alloy head on a twist flute body. Four flutes share the chip load and lift the chip out of the bore rather than packing it in, keeping the wall smooth in blockboard, melamine faced board, chipboard and MDF.

Diameters run 12 mm to 80 mm, 30 sizes: 12 to 28 mm in 1 mm steps, then 30, 32, 34, 35, 36, 37, 38, 40, 50, 53, 55, 60, 65, 70 and 80 mm. Length is 70 mm with 57 mm also available, and the shank follows the diameter: 10 mm to 28 mm, 11 to 18 mm at 30 to 40 mm, 19 to 25 mm at 50 to 80 mm.

Both hands are stocked, black right and orange left, because neighbouring spindles on one boring head turn opposite ways. Each bit is tubed on its own, 50 to an export carton. It fits woodworking drilling equipment and CNC machines, and customisation to drawing is supported.

A hinge bit is bought on flute, edge and fit.

• Four flutes — four cutting edges split the chip load and clear chips as the bore deepens, keeping the wall smooth.
• Tungsten steel alloy head — a tungsten steel alloy head in a steel body, so the edge survives repetitive boring.
• 30 diameters, 12 to 80 mm — 12 to 28 mm in 1 mm steps, then 30, 32, 34, 35, 36, 37, 38, 40, 50, 53, 55, 60, 65, 70 and 80 mm.
• 70 mm, or 57 mm — 70 mm overall as standard, 57 mm for shallower heads, on every diameter listed.
• Shank matched to diameter — 10 mm at 12 to 28 mm, 11 to 18 mm at 30 to 40 mm, 19 to 25 mm at 50 to 80 mm.
• Right and left hand — both rotations stocked; black right hand, orange left, so direction is read off the bit.
• Precise cutting edges — sharpened edges shear the fibre instead of crushing it, which limits splintering at the rim.
• Concentric shank — ground concentric with the head, so the centre of rotation stays balanced as it turns.
• High temperature resistance — the head holds up under the heat of repetitive boring in MDF and chipboard.
• Tube per bit, 50 per carton — one transparent plastic tube each; 50 pieces fill a standard export carton.

The usual choice is a cheap bit replaced every few weeks, or an import with a long lead. Neither keeps a boring head running, so this bit is stocked to remove that choice.

• One order covers the whole cupboard range — 12 to 80 mm on one list means the 26 mm, 35 mm and 40 mm cups on the same job arrive together.
• Fewer panels reach the filling bench — precise edges plus four-flute evacuation leave the melamine face intact, so a cup does not mean a repair.
• No spindle waits for a direction — both hands are stocked, so a left-hand spindle is serviced from the same order as the right-hand one.
• No adapter on the big cups — the shank grows to 25 mm at 80 mm diameter, so a large bit is not squeezed into a 10 mm collet.
• Feed does not stall mid-panel — engineered flutes move chips out of the bore instead of packing them, which matters most in MDF and particleboard.
• Two lengths, one part number — 70 mm and 57 mm cover deep and shallow boring heads without a second purchase route.
• Sizes to drawing — customisation is supported, so a diameter, length or shank outside the list can be quoted.
• Counting stock stays simple — one tube per bit, 50 per carton, so a stocktake is a carton count.

12 mm to 80 mm, 30 sizes. The list runs 12 to 28 mm in 1 mm steps, then 30, 32, 34, 35, 36, 37, 38, 40, 50, 53, 55, 60, 65, 70 and 80 mm, all at 70 mm overall length.

Yes, with the right feed and a sharp edge. The cutting edges are sharpened to shear the fibre rather than crush it, four flutes clear the chip as the bore deepens, and that combination is what limits splintering round the rim.

Yes, but it is the same bit in a different colour. Right hand is black and left hand is orange, so a boring head with spindles turning opposite ways is serviced from one order.

No. The shank grows with the diameter. It is 10 mm from 12 to 28 mm, 11 to 18 mm from 30 to 40 mm, and 19 to 25 mm from 50 to 80 mm, so check the collet against the size you are ordering.

70 mm is standard; 57 mm is also available. Both are made for every diameter in the list, so a deep boring head and a shallow one can be fitted from the same range.

All natural woods and man-made boards. Blockboard, melamine faced board, chipboard, MDF, plywood, particleboard and hardwood are all listed applications, with blind holes for concealed hinges the main use.

One bit per transparent plastic tube, 50 pieces per carton. The outer carton is a standard export box, which is what keeps the edges intact in transit.

Yes. Customisation is supported. Diameter, overall length and shank can be made to drawing, so a special hinge pattern can be quoted rather than improvised.