The right fit

By Jeremy Edison

Above: Ball-lock retainer inserts allow die builders to modify existing retainers and create entirely new retainers in-house.

Last-minute engineering changes, tight tolerances or special part runs no longer delay project lead times

May 2017 - When it comes to retainers, we’re not talking about a visit to our kid’s orthodontist, but rather a vital tooling component critical to daily stamping operations. Ball-lock retainers are designed as high-precision die components that secure and align piercing and forming punches and corresponding die buttons. These essential tools bring stampers optimum production efficiencies by saving time and labor costs when completing a tool change during production runs. Chances are, most shops have one or two trusted retainer styles that are regularly used in their tool room. 

But what happens when a new part run requires adjustments? Or what about those short-run jobs that require a number of improvements? What if the deadline for completing the part run doesn’t allow time for a lengthy tool build?

Each of these scenarios play out on a daily basis in job shops around the world. While options for custom ball-lock retainers can be acquired, lead times of three or even four weeks can quickly thwart production goals and send costs skyrocketing. Fortunately, there are options to sidestep long lead times and added costs while still meeting customer demands. Ball-lock retainer inserts allow die builders to modify existing retainers and create entirely new retainers in-house. This option can bring significant efficiencies in terms of increased production time, reduced lead time, and reduced labor needs.

FFJ 0517 stamping image1

Left: Punch plate hole specifications illustrate the straight-line geometry and the simple set of holes and counter-bore that accommodate the retainer insert. Right: Specifications for a retainer insert.

Standard versus custom

Standard ball-lock retainers such as trio, end and square configurations are typically available at a fairly quick turnaround from tooling manufacturers. Most of these standard retainers, however, only allow for one punch to be fixed in the retainer, can be bulky and often restrict the spacing of punches within the station because of the large footprint.

Custom ball-lock retainers can bring significant flexibility to stamping operations. The disadvantage is the need for stampers to go outside of their facility to have a custom retainer manufactured. Custom builds require a blind, flat-bottomed, precision-angled hole that is difficult to achieve. The designs often require significant lead time from the tooling manufacturer. Most shops simply can’t afford such delays. Lead time is just one deterring factor. Because of the precision engineering involved in creating the custom retainers, it can cost hundreds, even thousands of dollars to produce. 

Despite challenging lead times and costs, implementing a custom retainer has several benefits. Custom retainers allow die builders to position punches more closely together within tighter tolerances. This feature can help minimize progressions and reduce die design and overall costs, while enabling more stamping activity per station.

What’s the alternative?

One way to avoid the time and costly challenges of a custom retainer—while still meeting schedules—is to use retainer inserts. Fully compatible with virtually any ball-lock punches and dies, retainer inserts allows for the creation of new special retainers in-house, or modification and reuse of existing retainers, all while holding punches securely and accurately.

Using a variety of DIY techniques in house, it will take only a couple of days, or perhaps even a few hours, to modify or create a new retainer by using straight-line machining and following instructions from the retainer insert manufacturer. 

The HP Accu-Lock Special Retainer Insert from White Bear Lake, Minnesota-based Wilson Tool International simplifies the process for die builders by eliminating the need for complicated jigs, inspection fixtures and specialized knowledge to machine ball holes into the punch plate. Punches are held securely in place with a straight-line machined hole that die builders can create themselves.

HP Accu-Lock Retainer Inserts can help die builders locate punches in exceptionally tight areas, which may not have been possible with a standard retainer. Without bolts or locating dowels, the die builder simply machines the retainer and the punch hole together to assure the exact location as required for the job.

Custom retainers and the HP Accu-Lock Retainer both allow die builders to better utilize progressive die setups by creating smaller dies. With the ability to reduce the gaps between punches, die builders can help reduce the number of required progressions. Such designs will increase production speed, which is essential for successful stamping applications.

Say a particular part run delivers 30 parts per minute with 10 progressions. A progression might take up 2 seconds of that operation. If use could eliminate one of those progressions’ nesting capabilities, it would cut 2 seconds off production time and thus increase productivity by 10 percent. In high-volume stamping operations, every second counts.

Standard sizes of retainer inserts for both heavy-and light-duty applications can help die builders accommodate a variety of ball-lock seat sizes. Most tooling manufacturers offer retainer inserts for punch body sizes in diameters ranging from 3⁄8 in. to 1 1⁄4 in. [10mm to 40mm] for heavy-duty applications and 1⁄4 in. to 1 in. [6mm to 38mm] for light-duty applications. 

FFJ 0517 stamping image2

Choosing inserts

While the majority of retainer inserts are easily designed with a DIY approach, some retainers can prove challenging when it comes to locating the punch. If instructions from the tooling manufacturer for creating the hole in the retainer are complicated and unyielding, that can lead to stumbling blocks in the tool room. In these instances, the retainer insert usually features multiple angles designed to match the punch hole. If the machining process strays by even just a few thousandths of an inch, the hole and insert will not line up correctly, throwing off the ability to achieve required hole and part tolerances. 

Other characteristics to look for when selecting a retainer insert include the footprint and level of machining required. Larger footprints can prove challenging as it becomes more difficult for die builders to use space on the retainer and locate punches within close proximity to one another. For the level of machining required, some retainer inserts necessitate the die builder to use wire EDM and a highly skilled machinist to match the pitch of the insert shape to assure proper installation.

Stampers should work with their tooling manufacturer to implement retainer inserts that are created using straight-line geometry. This design allows die builders the luxury of quick and easy installation and straightforward machining practices for creating custom retainers in-house.

Tool room flexibility

Retainer inserts give ultimate control and optimum flexibility in the tool room while lowering costs. A stamper also recoups efficiencies by not having to wait nearly a month for a custom retainer, and can perform changes to existing ball-lock dies and retainers on the fly. 

Most tooling manufacturers can deliver retainer inserts within a relatively quick timeframe. With a pre-built, standard inventory, tooling manufacturers should be able to provide same-day shipment for most requests.

Punch location also brings flexibility to the tool room. Moving a punch from one location to another or placing a larger punch within the same space is easily accomplished in a matter of hours. Finally, any tool room has seen its share of obsolete tools, dies and retainers. Whether these tools were used for a one-off job, or a regular run that’s no longer in production, the wasted material and expense of these obsolete or unused tools can negatively impact the bottom line. With the opportunity to re-use retainer inserts and modify these retainers, obsolete tools are now reusable. 

Overarching ROI

By implementing retainer inserts, stampers will no longer send costs through the roof or delay projects by weeks simply to purchase a custom retainer. It’s also no longer necessary to force workarounds when faced with the limitations of standard retainers. Die builders and tool rooms the world over can implement ball-lock retainer inserts and modify or create entirely new retainers in-house in a fraction of the time it takes to create custom retainers. These benefits translate to serious savings for stampers. FFJ

Jeremy Edison is the Stamping Product Manager at Wilson Tool International.


  • Wilson Tool International
    White Bear Lake, Minnesota
    phone: 866/752-6531

Company Profiles





Camfil APC - Equipment Trilogy Machinery Inc. Metamation Inc. Admiral Steel
Camfil APC - Replacement Filters



Alliance Steel
Donaldson Company Inc. AMADA AMERICA, INC. Messer Cutting Systems Inc.



Mazak Optonics Corp.


Enmark Systems Inc.
MetalForming Inc. MC Machinery Systems Inc. Peddinghaus Lantek Systems Inc.
RAS Systems LLC Murata Machinery, USA, Inc.




TRUMPF Inc. Davi Inc. SigmaTEK Systems LLC
Steelmax Tools LLC


Trilogy Machinery Inc. Striker Systems


MTS Sensors



Bradbury Group


Mate Precision Tooling AIDA-America Corp.
Burghardt + Schmidt Group EMH Crane Rolleri USA Nidec Press & Automation
Butech Bliss Fehr Warehouse Solutions Inc.



Red Bud Industries UFP Industrial AMADA AMERICA, INC. Alliance Steel


Automec Inc.



Advanced Gauging Technologies MC Machinery Systems Inc. BLM Group
Mayfran International


SafanDarley HGG Profiling Equipment Inc.


Cincinnati Inc.


Prudential Stainless & Alloys
ATI Industrial Automation LVD Strippit Hougen Manufacturing


Lissmac Corp. Scotchman Industries Inc.


Barton International
Osborn Trilogy Machinery Inc. Behringer Saws Inc. Jet Edge Waterjet Systems
SuperMax Tools


Cosen Saws Omax Corp.
Timesavers FAGOR Arrasate USA Inc. DoALL Sawing



MetalForming Inc. HE&M Saw American Weldquip
Beckwood Press Co.


Savage Saws Strong Hand Tools
Triform Titan Tool Supply Inc.


T. J. Snow Company

TPMG2022 Brands