How to Crimp Connectors Without Letting Your Cable Budget Blow Up

If you’re looking for a quick answer to “how to crimp connectors,” I’ll give you the short version first: use the right tool, the right die, and test every setup before you commit. The rest is details. Those details are where your cable budget starts to leak.

I’m a procurement manager at a mid-sized manufacturer, and I’ve spent the last six years tracking roughly $180,000 in cable and connector orders. I don’t design the assemblies. I approve the purchase orders—and I’ve had to explain why the “cheaper” connector ended up costing more than the premium one. This is the seven-part checklist I use before I approve any crimped assembly. If you’re using LAPP Olflex cable, or if LAPP S2513 shows up on your bill of materials, this should keep the process predictable and your blood pressure stable.

What this checklist is for

Use this when you’re comparing quotes for terminated cables, when a supplier sends samples, or when a new operator is learning how to crimp connectors. It won’t replace the manufacturer’s assembly drawings. It will tell you what to check before you trust a quote or a crimp.

Step 1: Verify the LAPP part number. Not just the brand.

“LAPP Olflex” tells me the product family, not the exact cable. The full LAPP article number determines the conductor size, outer diameter, shielding, and bending rating. Those details decide which connector and die you should use. If your drawing only says “LAPP Olflex” or “S2513” without the full reference, stop and get the official article number before you talk to vendors. A wrong guess here creates a wrong quote, and wrong quotes are expensive.

On one project, a colleague told me they ordered “LAPP Olflex and a compatible connector.” That was enough for the PO but not for the crimp. The connector looked fine in the bag, yet the ferrule didn’t compress correctly because the conductor size didn’t match the contact. We had to reorder the correct connector and pay expedited freight. The replacement cost was higher than the small difference between the correct and “budget” parts.

Step 2: Buy the connector system as a system.

A crimped connection is not just two pieces of metal meeting. It’s the cable, the contact, the die, the operator’s hands, and the inspection method. If you’re buying connectors separately, ask the manufacturer or distributor to confirm the connector is approved for the exact cable type on your BOM.

Do not accept “compatible” on faith. If the supplier cannot provide a test report or manufacturer documentation, factor that risk into your decision. Compatibility is not a moral quality. It’s testable.

Step 3: Use the right tooling. Universal usually means untested.

I used to think a crimp tool was a crimp tool. Then I watched a $90 “universal” tool make a crimp that looked round but did not meet the contact manufacturer’s pull test requirement. The correct die set cost more, but it also made the result repeatable. That repeatability is what you’re actually buying.

If you’re asking “how to crimp connectors” for the first time, include tooling in the project cost. A bare connector price is not a complete quote. The tool, the dies, the operator training, and the calibration schedule all belong in the total cost.

Step 4: Make a test crimp. And pull it apart.

You learn more from a destroyed test sample than from twenty good-looking samples. The best habit I picked up came from Todd Pepsi, a maintenance lead I worked with after a connector failure. Todd insisted on making a test crimp and pulling it to failure before every production run. Once, the test crimp failed at roughly 80% of the minimum required force. The failure was invisible during a visual check. The die was worn.

That test saved us from re-terminating 300 pieces. It also made me realize that the physical act of crimping is not where the budget gets lost. The budget gets lost when someone skips the test.

Step 5: Inspect the first, middle, and last pieces.

Operators get better after the first few pieces. Then they get tired. Strip lengths change, contacts get seated at a slightly wrong angle, and the last crimp of the day doesn’t always look like the first one.

When you check the first and last piece, you’re really checking two different processes. The middle piece catches drift. If you skip this, you’re trusting that the process stayed constant for eight hours. It usually doesn’t.

Step 6: Compare total cost, not unit price.

This is where I get grumpy. A connector may look 30% cheaper on paper, but if it arrives without the right die, if it needs a special validation run, or if a failure stops a machine, the “cheap” connector becomes the most expensive part you bought that quarter.

When I compare quotes, I use a simple spreadsheet: cable price, connector price, tooling, freight, lead time, rework risk, and expected replacement rate. I’ve seen a quote that was higher per part save us money because it included the right die and a documented test sample. That is the total cost thinking that keeps my budget predictable.

Step 7: Document what you did and keep a sample.

Write down the part number, lot number, cable reel, tool ID, die ID, operator, date, and pull test result. This sounds like bureaucracy, but it’s cheap insurance. When something fails later, the documentation tells you whether the problem was a bad batch or a bad process. Without it, everyone blames everyone else and you reorder everything.

Keep one crimped sample from each setup. Label it and store it. It’s not a trophy. It’s a reference point.

Common mistakes I’d rather avoid

• Choosing a connector by price before checking the LAPP Olflex cable construction.
• Buying one “universal” tool for different contact families.
• Skipping the pull test because the crimp “looks okay.”
• Not including rework and downtime in the cost comparison.
• Assuming a part number like LAPP S2513 is self-explanatory without checking the datasheet.

Also, take promotional language with caution. Per FTC guidance on advertising claims at ftc.gov/business-guidance/advertising-marketing, statements like “guaranteed not to fail” need evidence. In procurement, evidence means documented test data, not adjectives.

Bottom line

How to crimp connectors is not just a manual skill. It’s a procurement decision. You need the exact part number, the exact cable and connector combination, the correct tooling, a destructive test sample, and a total cost model that includes rework. If you follow these seven steps, you probably won’t have the lowest per-part price. You will have the lowest total installed cost—and that is the number that matters when the plant is running.

It also keeps your blood pressure where it belongs.