We hear a version of this question a lot: "We've run Jergens Ball Lock on our horizontals for years. Should the new cell be zero-point, or more of the same?" There's no single answer. Both systems locate a fixture and hold it down without indicating. They get there differently, and that difference decides which one fits your next machine.
This is not a "ball lock is old, zero-point is new" article. Ball lock is still a sound choice for a lot of fixture-plate work. Jergens itself sells both: the Ball Lock Mounting System and its own ZPS zero-point modules. The useful question is which job you're asking the interface to do.
Two systems, two jobs
Ball lock joins two flat plates: a fixture plate and a subplate, tombstone face or machine table. The operator drops the fixture plate on, pushes shanks through it into bushings, and tightens a set screw in each shank.
Zero-point clamping puts the locking mechanism in a receiver on the machine side. The fixture, vise or pallet carries pull studs underneath. You lower it on and the receiver grabs the studs. Depending on the model, that happens by hand, by spring with air release, or by a command from the machine or robot.
So the real split isn't accuracy. It's who does the locking and where the hardware lives.
How ball lock locates and locks
Jergens describes it plainly: it locates like a pair of locating pins. Two precision receiver bushings sit in the subplate. Two shanks pass through liner bushings in the fixture plate and into those receivers. Jergens says two locating points are all you need. More than two "is a hindrance rather than a help."
Locking is mechanical. A set screw in the shank head pushes a center ball, which drives three balls out into a taper in the receiver bushing. That pulls the plates together. Jergens quotes a maximum of two and a half turns to lock, against about ten turns for a 1/2-13 cap screw.
A few details matter when you plan a station:
- Four shanks is the usual starting point. Jergens recommends at least four in most cases: two to locate and lock, two to lock only. The lock-only shanks go through clearance holes about 0.030 in. (0.76 mm) oversize, so they don't fight the locating pair.
- Accuracy depends on how well you machine the subplate. Jergens states ±0.0005 in. (±0.013 mm) of true position when the receiver bushing center distance is held to ±0.0002 in. (±0.005 mm) and two primary liners are used. With one primary and one secondary liner, it's ±0.0015 in. (±0.04 mm).
- Hold-down force scales with shank size. The metric shank table lists maximum hold-down force per shank from 3.3 kN (13 mm shank) up to 88 kN (50 mm shank), at the recommended set-screw torque.
- Plate thickness is fixed by the shank. Each shank length matches a fixture plate thickness, and Jergens calls the section under the shank head critical.
- Heat. Shanks are 4340 steel at 40–45 HRC, listed for -30 °C to 200 °C. Jergens also notes that thermal growth of the plate can change the center distance and repeatability.
Jergens says fixtures can often be swapped in under a minute. For an operator with a hex key and a well-built subplate, that's believable.
How zero-point locates and locks
A zero-point receiver locates the stud on a taper and locks it mechanically inside the module. On NEXTAS MFG receivers, the catalogue describes mechanical self-locking with pneumatic unlocking, plus air-tightness checking and cleaning of the stud bore. The listed MFG-V1 receivers (85, 125, 160 and 195 mm outside dimension) specify <0.003 mm repeatability and 4 kN to 40 kN clamping force by size.
You don't have to start with air. The NEXTAS 52 mm and 96 mm manual zero-point plates release by hand, need no air line, and list <0.005 mm repeat positioning with 20 kN (52 mm) or 30 kN (96 mm) clamping force. The pneumatic zero-point plates use the same 52/96 mm stud families. They are spring-locked and air-released, list <0.005 mm, and range from 9 kN to 40 kN depending on the model.
The practical point: the top of the fixture stays clear. Nothing passes through the fixture plate and nothing needs a wrench from above.
Side-by-side comparison
| Decision point | Jergens Ball Lock | Zero-point clamping (NEXTAS examples) |
|---|---|---|
| How it locates | Two shanks in two receiver bushings, like locating pins | Pull studs on a taper inside the receiver |
| How it locks | Set screw drives balls into the bushing taper | Mechanical lock in the receiver. Manual, or spring-locked with air release |
| Who actuates | Operator with a hex key, from the top | Operator (manual plate), or machine/robot through a valve |
| Published repeatability | ±0.013 mm true position with two primary liners and ±0.005 mm bushing spacing | MFG-V1 receivers <0.003 mm. 52/96 mm plates <0.005 mm |
| Force figure | Max hold-down per shank, 3.3–88 kN by size | Clamping force per receiver, 4–40 kN by model |
| Loose parts | Shanks come out with each change | Studs stay bolted to the fixture or pallet |
| Top-side access | Shank heads sit on the plate top | Top surface free for the part and tools |
| Air and controls | None | None on manual plates. Air, valves and optional sensing on pneumatic models |
| Clamp-state feedback | Not part of the basic system | Sensor-ready receiver formats for PLC or robot interlocks |
Read the numbers carefully. Jergens gives a true-position figure that depends on how accurately you bore the subplate. NEXTAS gives a module repeatability figure. Hold-down force per shank and clamping force per receiver aren't measured the same way either. Use the table to shortlist, then test your own fixture on your own machine.
Where ball lock is the better fit
I'd stay with ball lock, or pick it, in these cases:
You already own the subplates. If your HMC tombstones and VMC subplates are bored for receiver bushings and your fixture library carries liners, that's real money already spent. Replacing it because zero-point is newer makes little sense unless something else changes.
Big, flat fixture plates, swapped by hand. A large plate with two locating shanks and several lock-only shanks spreads hold-down across the plate. On a manually loaded HMC where an operator changes fixtures a few times a shift, that works well.
No air at the station. Ball lock needs a hex key and nothing else. (So do NEXTAS manual plates, to be fair.)
Stack height is tight. The fixture plate sits straight on the subplate. Surface-mounted zero-point receivers or plates add height. If you're already short on Z, check that before anything else.
Cost per station is the main driver. A ball lock station is bushings, liners and shanks. No valves, no air prep, no PLC work. We don't publish prices for comparison here, but the bill of materials is simpler.
Where zero-point earns its cost
A robot or pallet changer is doing the loading. This is the biggest one. A robot can't push four shanks through a plate and torque four set screws. With a pneumatic receiver, the robot sets the pallet down, the valve drops air, and the springs lock. The MFG receiver modules also come in sensor-ready formats, so the PLC can check clamp state before the spindle starts. Our I/O and fault-state checklist for robot-loaded cells covers what to wire.
5-axis work where the top of the fixture matters. Shank heads on the plate top take space and need tool clearance. Studs underneath don't.
Vises and small fixtures that change many times a day. On a high-mix VMC, the operator lifts the vise off and drops the next one on. There are no loose shanks to drop in the chip pan and no torque to get right.
You need to know the pallet is seated. NEXTAS MFG receivers include air-tightness checking and stud-bore cleaning in the catalogue description. A ball lock station relies on the operator to clean and seat it. That's fine with a careful operator and a risk in a lights-out cell.
Tighter published repeatability, on modules you don't have to bore to ±0.005 mm yourself. You still need an accurate pocket or plate, but the locating geometry is inside the receiver.
Already running ball lock?
Send us your fixture drawing or the current ball lock subplate layout. We'll check whether a zero-point plate can replace it or sit alongside it, and tell you plainly if it isn't worth changing.
Running both in one shop
Most shops that ask about a "Jergens Ball Lock alternative" don't need to convert everything. A common split:
- Keep ball lock on HMC tombstones and big fixture plates where it already works.
- Put manual zero-point plates on the VMCs that run vises and short jobs.
- Go pneumatic only on the machine that's getting a robot or pallet changer.
Two standards in one building need discipline. Label pallets, keep separate spare stock, and don't let anyone "make it fit." Our post on retrofitting zero-point onto an existing table compares T-slot, sub-plate and grid-plate mounting. If you want to bolt a zero-point plate onto an existing ball lock subplate through an adapter, send us the drawings. Check stack height and stiffness before committing.
The ball lock and zero-point interfaces don't interchange. NEXTAS studs won't lock in a Jergens receiver bushing, and the reverse is also true. Any mixed setup needs its own adapter or plate.
What to send for a comparison quote
You'll get a useful answer faster with these:
- Machine model, table size and available Z height.
- Current subplate or tombstone drawing, with receiver bushing positions if you run ball lock.
- Fixture or pallet sizes, total loaded mass and the heaviest cut you run.
- How changes happen today (operator, pallet changer, robot) and how they'll happen in a year.
- Whether air is available at the table and whether the PLC needs a clamp signal.
If something is unknown, say "unknown." We'd rather ask than guess. The quote guide has a fuller list, and what a zero-point system costs covers the line items people tend to miss.
Not sure if your next cell should be ball lock or zero-point?
Send the machine, the subplate drawing and how fixtures get loaded. NEXTAS engineering will suggest a receiver or plate layout, list what still needs checking, and quote the parts. If ball lock is the better fit for that machine, we'll say so.
FAQ
Is NEXTAS affiliated with Jergens?
No. NEXTAS is not affiliated with, endorsed by, or sponsored by Jergens, Inc. Jergens and Ball Lock are trademarks of their owner. The names are used only to describe the system a buyer already has or is comparing.
Can NEXTAS zero-point studs fit Jergens Ball Lock receiver bushings?
No. They are different interfaces. A ball lock shank locks into a receiver bushing with three balls driven by a set screw. A zero-point pull stud is captured inside a receiver module. Plan a new interface or an adapter, not a parts swap.
Is zero-point always more accurate than ball lock?
Not as a blanket rule. Jergens states ±0.0005 in. (±0.013 mm) of true position when the receiver bushing center distance is held to ±0.0002 in. and two primary liners are used. NEXTAS lists <0.003 mm repeatability for MFG-V1 receivers and <0.005 mm for its 52/96 mm plates. The figures are measured differently, so prove the full setup on your machine.
Do I need compressed air for zero-point clamping?
Not always. The NEXTAS 52 mm and 96 mm manual plates release by hand and need no air. Pneumatic plates and MFG receivers use air to unlock and stay mechanically locked without it. Confirm the pressure and circuit on the selected drawing.
Do I have to scrap my ball lock subplates to move to zero-point?
No. Many shops keep ball lock on the machines and fixtures where it works and add zero-point where changeovers are frequent or automated. Send the subplate drawing and we can review the options, including an adapter plate.