Adding a second machining source without doubling your workload
September 20, 2026
Most teams do not look for a second source until something has already gone wrong. It is worth doing while nothing is wrong, because a second source qualified under pressure is a second problem.
Why teams add one
- Continuity. A single shop is a single point of failure: a machine down, a key person gone, a factory relocation.
- Capacity. Your volume outgrows the shop, or the shop’s other customers crowd you out.
- Price discovery. Not to beat down the incumbent, but to know whether the price you pay is normal.
- Geography. A second region with a different exposure to tariffs, freight routes and local disruption.
The first two are the durable reasons. The others are useful side effects.
Choose the right part to move
The wrong first candidate makes the exercise fail for reasons that have nothing to do with the supplier.
| Good first candidate | Poor first candidate |
|---|---|
| Design frozen for a year or more | Still going through revisions |
| Real annual volume, released regularly | One order every two years |
| Tolerances the incumbent holds without drama | The part nobody can make reliably |
| A delay would be uncomfortable, not catastrophic | The part that stops your line |
| Material stocked in the new region | An exotic alloy with a long import chain |
You are qualifying a supplier. Use a part that isolates the supplier as the variable.
Keep everything else identical
The comparison is worthless if two things changed at once.
- Same drawing, same revision. Not a cleaned up version. If the drawing needs fixing, fix it for both suppliers and record it.
- Same inspection requirement. Ask the new supplier for exactly what you get today, then compare like for like.
- Same quantity and the same quantity breaks.
- Same delivery basis, so the landed cost comparison is honest.
Then insist on one thing you may not have today: measured values in the report, not ticks.
What to look at besides price
Price is the easiest thing to compare and the least predictive. Weight these more heavily:
- Did they ask a question about the drawing? A supplier that quotes a toleranced part without a single question has not read it.
- Did the first article report contain real numbers, and where did they sit in the band? Values clustered at one limit tell you the process is capable but biased, and the batch will drift.
- How did they behave when something was wrong? Nothing tells you more than the first non-conformance. Manufacture one if you have to, by tightening a feature on a trial part.
- Is the lead time repeatable? One fast order proves nothing. Three in a row does.
A realistic timeline
- Weeks 1 to 2: send the package, get a quote and DFM notes back, compare scope not price
- Weeks 3 to 6: first article, measured and reported, reviewed against your incumbent’s numbers
- Weeks 7 to 12: trial batch at a real quantity, shipped and received the way production would be
- Quarter 2: a second batch, then a decision about volume split
Buyers who compress this usually end up with a supplier that is cheap on paper and unproven in practice.
Where a hub changes the arithmetic
The reason teams postpone a second source is the workload: finding shops, auditing, learning a new set of terms and carrying the risk during the trial. Buying through a hub moves most of that off your desk, because the qualification, the audit and the inspection are done before your part is placed and the commercial relationship is a single purchase order.
What you should still do yourself is the part that matters: pick the right first part, keep the package identical and read the first article report properly.
A scorecard you can actually use
Score each supplier out of five on these six, before price enters the conversation.
| Criterion | What a 5 looks like |
|---|---|
| Drawing engagement | Named a specific feature and asked a real question |
| Inspection evidence | Measured values, instruments named, spread visible across pieces |
| Date discipline | Lead time with a starting point, then held on three consecutive orders |
| Communication | Proactive on bad news, written, same day |
| Commercial hygiene | Company account, clear terms, a written position on non-conformance |
| Response to a problem | Owned it, explained the cause, changed something |
A supplier scoring 4 or more on five of six at a slightly higher price is a better second source than one scoring 3 at a lower one. The point of a second source is reducing risk, and a cheap unreliable supplier adds risk rather than removing it.
Keeping both suppliers honest without playing them off
Split the volume in a stable ratio rather than moving it around every quarter. Both suppliers can plan, both keep the work, and neither is guessing. Review the split once a year against the scorecard rather than against the last invoice, and tell both what the criteria are. Suppliers behave better when they know they are being measured on something other than price.
The questions we ask a shop before it joins are published in the shop audit checklist, and the process is on how it works. When you have picked your candidate part, send the drawing.
Questions we get on this
Which part should I move to a second source first?
Not the hardest and not the least important. Pick a part with a stable design, a real annual volume, a tolerance your current supplier holds comfortably and consequences you could absorb if a batch were late. You are testing the supplier, not the part.
Do I need to tell my current supplier?
That is a commercial judgement rather than a technical one. Most buyers dual-source quietly at first and tell the incumbent once the second source is proven. What matters is that you do not use a quote from one to beat down the other, which damages both relationships.
How long does qualifying a second source take?
Plan on one quarter for a first article and a trial batch, and two before you would move meaningful volume. Anything faster is usually a supplier being tested on price rather than on performance.
Have a part like this?
Send the drawing. We shortlist the shop we place it with that run the process and material, and answer within 24 business hours.
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