![](https://www.viiju.com/images/products/parts-machines/thread-tapping/slides/thread-tapping-1.webp) ![](https://www.viiju.com/images/products/parts-machines/thread-tapping/slides/thread-tapping-2.webp) ![](https://www.viiju.com/images/products/parts-machines/thread-tapping/slides/thread-tapping-3.webp) ![](https://www.viiju.com/images/products/parts-machines/thread-tapping/slides/thread-tapping-4.webp) [](#) [](#) - [](#) - [](#) - [](#) - [](#) # Thread Tapping Machines for MCB / MCCB Production Terminals, terminal nuts, trip-mechanism brackets and die-cast inserts inside a miniature circuit breaker share the same characteristics: small parts, fine threads, high volume and tight burr limits. Starting from a 28-model thread tapping machine platform, we have selected the machines that fit MCB production — covering a regular tapping range of M1.6–M16 at 3–50 parts per minute, for stand-alone use or inline integration. From Terminal Tapping to Drilling & Chamfering of Stamped Steel Parts ### 3 ~ 50 PPM Cycle rate across the range ### M1.6 ~ M32 Standard tapping range ### Semi - Full Automated For MCB production Overview ## Typical Tapping Points on an MCB / MCCB | Part | Material | Typical thread | Process focus | Recommended machine | |---|---|---|---|---| | Terminal / terminal block | Brass, copper | M3~M6, mostly blind holes | Chamfer and deburr the hole mouth; full thread form, go/no-go gauge qualified | Rotary-table drilling & tapping machine; servo-head tapping machine | | Terminal nut / insert nut | Brass, steel | M3~M8 | High volume, parts tumble easily, need oriented feeding | Straight-slot automatic tapping machine; 2-up tapping machine | | Fixed-contact bracket / trip bracket | Stamped steel, stainless steel | M2.5~M5 | Thin-sheet tapping; avoid part distortion and tap deflection | Rotary-table drilling & tapping machine; automatic 2-up tapping machine | | Linkage rod / pivot pin | Steel, brass | M2~M4 | Tight small-hole location, often combined with drilling and reaming | Rotary-table drilling, reaming & tapping machine; multi-station machine | | Die-cast insert / small internal part | Aluminium / zinc die-casting | M3~M6 | Soft material, tap tends to stick; needs smooth chip evacuation | Rotary-table automatic drilling & tapping machine; semi-automatic machine | | Housing screw hole (self-tapping) | Thermoplastic / thermoset | — | Mainly chamfering and flash removal, tied to the assembly line | Multi-station chamfering machine; automatic rotary chamfering & tapping machine | Table — Typical MCB parts and matching machine configuration ## Recommended Models For MCB / MCCB Production There are dozens of models available from maual, semi-automated to full automated thread tapping machines. Here listed a few models specialized for MCB / MCCB production. The selection was based on 3 hard requirements: the machine can handle small parts, can tap fine threads reliably, and can be fed continuously in volume. ![](https://www.viiju.com/media/yootheme/cache/53/model11-520-53f840af.webp)HJGS-11 (For Screw) Fully Automatic Rotary Drilling, Reaming & Chamfering Machine A rotary multi-station layout fed by a vibratory bowl performs drilling, reaming and chamfering sequentially on the table. The parts in the bowl are M3–M6 class screws, comparable in size to breaker terminal screws and small linkage pins. - Rotary multi-station: operations concentrated, one datum throughout - Vibratory bowl orienting feed, ideal for small screws and pins - Reaming holds small-hole accuracy and leaves stock for later tapping or riveting ![](https://www.viiju.com/media/yootheme/cache/ed/model12-520-ede27ebf.webp)HJGS-12 (For Nut, Straight-Slot) Fully Automatic 2-Up Tapping Machine Parts are fed by a vibratory bowl and travel along a straight slot into two stations where two taps work simultaneously, producing two parts per cycle. The sample parts are small brass and steel nuts — exactly the shape of breaker terminal nuts and insert nuts. - 2-up design, roughly doubling output from one machine - Short straight-slot feed path reduces jamming of small nuts - Independent tap per station, easy to set per thread size ![](https://www.viiju.com/media/yootheme/cache/6c/model14-520-6ca54845.webp)HJGS-14 Rotary Automatic Drilling & Tapping Machine An eight-station rotary layout where fixtures locate on the profile of small die-castings and drilling and tapping heads are distributed around the table. The sample part is a small aluminium die-casting with a sloped face and internal thread, close to breaker internal castings. - Eight stations for parallel operations and a high cycle rate - Clamp-type location suits irregular small die-castings - Chip evacuation clearance between stations for aluminium ![](https://www.viiju.com/media/yootheme/cache/33/model26-520-339f9698.webp)HJGS-26 Rotary Automatic Drilling, Chamfering & Tapping Machine A three-operation rotary machine: drilling, chamfering and tapping are carried out at separate stations on the table, so one loading produces a finished part. Ideal for terminal-type parts with strict requirements on thread-mouth burrs. - Drill–chamfer–tap in one machine, less handling and re-clamping - Dedicated chamfering station removes burrs and rolled-over edges - Multiple power heads, cycle governed by the single table index ![](https://www.viiju.com/media/yootheme/cache/b9/model17-520-b9e264c1.webp)HJGS-17 Fully Automatic Drilling, Chamfering & Tapping Machine A vertical multi-head layout that concentrates drilling, chamfering and tapping on one machine, with touch-screen PLC control. It replaces three separate machines with a single loading operation. - Four power heads arranged in parallel — fewer machines, smaller footprint - Touch screen plus PLC, parameters stored and recalled per part - Less transfer between stations, avoiding secondary damage to parts ![](https://www.viiju.com/media/yootheme/cache/dc/model21-520-dc692207.webp)HJGS-21 Fully Automatic 2-Up Chamfering Machine A chamfering machine on the same platform as the 2-up tapping machine: vibratory bowl feeding, with heads on both sides chamfering two parts at once. The sample part is a small hex piece, used to remove burrs from hole mouths and end faces before or after tapping. - 2-up design with a cycle rate matched to the tapping machine - Can be placed before or after tapping as a deburring unit - Works with both steel and brass parts ![](https://www.viiju.com/media/yootheme/cache/5f/model20-520-5f6b3639.webp)HJGS-20 Semi-Automatic 2-Up Multi-Station Tapping Machine A 2-up multi-station machine; the part is a stamped steel sheet with a flange and several threaded holes, similar in shape to breaker brackets and base plates. The semi-automatic configuration suits high-mix, medium-volume steel parts. - 2-up multi-station: two parts with multiple holes per cycle - Semi-automatic loading for flexible changeover and lower tooling cost - Fixturing designed for stamped steel to prevent sheet distortion ![](https://www.viiju.com/media/yootheme/cache/f9/model3-520-f9bbdb71.webp)HJGS-3 Semi-Automatic Drilling, Chamfering, Tapping & Grooving Machine Adds a grooving function to drilling, chamfering and tapping; the sample part is a small die-casting. It suits parts with ring grooves, relief grooves or locating slots, completing all hole and groove work on one machine. - Four operations in one machine: drill, chamfer, tap and groove - For complex small parts where piece value is relatively high - Semi-automatic operation, good for prototyping and small orders ![](https://www.viiju.com/media/yootheme/cache/f9/model18-520-f94b9ea2.webp)HJGS-18 Manual Load 2-Up Automatic Tapping Machine Parts are placed into the fixture by hand and the machine performs 2-up tapping automatically. The sample part is a short sleeve with a blind hole on the end face. Hand loading eliminates the bowl feeder and orienting mechanism, keeping investment low and changeover quick. - Automatic 2-up tapping without a feeding mechanism - Low investment and small footprint for trial production - Changeover by swapping the fixture only; tolerant of irregular parts Model Recommendation ## Parts and Machining Close-Ups These are on-site photos of the selected machines running small parts, showing feeding, locating and tapping as it actually happens. ![](https://www.viiju.com/component/ajax/?p=cache/c2/twin-taps-300-c229c17a.webp&src=images/products/parts-machines/thread-tapping/details/twin-taps-300.webp&thumbnail=260,260,&hash=cbfbbf0b)Straight-slot 2-up: twin taps on small nuts ![](https://www.viiju.com/component/ajax/?p=cache/3a/auto-screw-feeding-300-3a02606a.webp&src=images/products/parts-machines/thread-tapping/details/auto-screw-feeding-300.webp&thumbnail=260,260,&hash=8ceacd9d)Orienting feed on the straight-slot machine ![](https://www.viiju.com/component/ajax/?p=cache/7f/drilling-and-tapping-300-7fd20e7a.webp&src=images/products/parts-machines/thread-tapping/details/drilling-and-tapping-300.webp&thumbnail=260,260,&hash=1d53d403)Drilling and tapping on one rotary table ![](https://www.viiju.com/component/ajax/?p=cache/6a/after-tapping-300-6a4ccc84.webp&src=images/products/parts-machines/thread-tapping/details/after-tapping-300.webp&thumbnail=260,260,&hash=f7c50420)Stamped steel parts after multi-hole tapping ![](https://www.viiju.com/component/ajax/?p=cache/98/small-aluminium-tapping-300-98a5ee71.webp&src=images/products/parts-machines/thread-tapping/details/small-aluminium-tapping-300.webp&thumbnail=260,260,&hash=fe365420)Small aluminium die-castings, fixture located ![](https://www.viiju.com/component/ajax/?p=cache/ce/hex-tapping-300-ce538081.webp&src=images/products/parts-machines/thread-tapping/details/hex-tapping-300.webp&thumbnail=260,260,&hash=f3229132)2-up chamfering of hex parts on both sides Need a tapping proposal based on your part drawings? Send us the part drawing, material, target cycle rate and thread specification. We will recommend a configuration from the 14 suitable models, covering power head selection, station layout, fixturing and feeding method. Part drawings / 3D files Material and thread size Target cycle rate (pcs/min) Inline production required? [ Get A Proposal ](https://www.viiju.com/contact "Technical and commerical proposal.")