Bigger Bores Shouldn't Mean More Setups

For years, machining large bores has come with a tradeoff: the bigger the diameter, the more likely you are to need a second operation, a workpiece rotation, or a completely different tool altogether. HEULE just closed that gap. Both the SOLO and BSF tool lines now handle bore diameters up to Ø 45.0 mm — bringing one-operation spotfacing, counterboring, and backspotfacing to a size range that used to force shops into extra setups.

Here's what's new, and why it matters on the shop floor.

SOLO — Large Diameters

SOLO has always been built around one idea: machine a spotface or counterbore on both sides of a bore in a single operation, without rotating or realigning the workpiece. The new SOLO 25 tool system extends that capability into larger parts.

What's new:

• Bore diameters now up to Ø 45.0 mm
• Counterbores up to 1.95 × bore Ø
• Maximum cutting width of 20.25 mm

How it works: SOLO relies on a centrifugal, spring-loaded mechanism. At activation speed, two sliding centrifugal weights move outward, and that linear motion converts to rotary motion through a rack-and-pinion system — extending or retracting the blade depending on spindle speed. No hydraulics, no external actuation. It's also robust enough to handle uneven or interrupted cutting conditions, which matters more as bore sizes (and the materials they show up in) get tougher.

Why it matters: Eliminating the need to rotate and realign large workpieces isn't just a convenience — it's a direct cut to process time and manufacturing cost, especially on parts where repositioning is slow or requires a second fixture.

BSF — Large Diameters

BSF takes a different approach to the same problem: back spotfacing and counterboring from the front side of the workpiece, with no need to flip or rotate the part at all.

What's new:

• Bore diameters now up to Ø 45.0 mm
• Bore-to-counterbore ratio up to 2.3 × bore Ø
• Maximum cutting width of 22.5 mm
• For shank diameters starting at 30.0 mm, BSF can now be configured as a double-bladed tool, cutting cycle time further

How it works: BSF is built for fully automatic operation — no torque arm, no machine modification required. The blade extends via centrifugal force from spindle rotation and folds back in when internal coolant is activated. That folding mechanism, combined with coolant pressure (20–50 bar), also flushes chips and debris out of the blade window as it retracts.

Why it matters: For bore diameters of 21.0 mm and up, BSF tools are custom-designed to the application. At 45 mm, that means shops that previously needed a drill, a separate countersinking tool, and manual turning of the workpiece can now do the same job from one side, in one pass.

The common thread

Whether it's SOLO's dual-side machining or BSF's back-side approach, both expansions solve the same underlying problem: larger bores used to mean more setups, more tool changes, and more manual handling. Neither tool line requires that anymore, up to 45 mm.

For shops running CNC production on parts in this size range, that translates to fewer tools in the machine, simpler tool management, and less non-cutting time per part.

See it in person

HEULE will be demonstrating both the SOLO and BSF large-diameter tooling at IMTS 2026, September 14–19 at McCormick Place, Chicago — Booth #431364.

Technical changes reserved. Specifications current as of 07.2026.