Ordering from a Mando Shop? A Procurement Checklist for Struts, Springs, and the 6.7 Cummins Exhaust Manifold

If you've ever ordered a batch of mando struts, a prototype t strut, or a replacement exhaust manifold 6.7 Cummins, you know how tempting it is to just pull three quotes, pick the cheapest, and move on. I did that for years. It cost us real money more than once.

I'm a procurement manager at a mid-sized auto parts distributor. I've managed our metal parts budget—roughly $180,000 in cumulative spend—for the past 6 years, negotiated with 40+ vendors, and logged every order in our cost tracking system. This checklist is the one I actually run through before any PO over $500.

There are six steps. If you source from a mando shop—or any supplier that does stamping, forging, or CNC work—this is for you.

Step 1: Match the Part to the Right Process First

Sounds obvious, but it's the most common mistake I see. Buyers ask a sheet metal stamper to quote a part that should be cast, or a forging shop to quote a thin stamped bracket. The quote comes back cheap, then the problems start.

Take the leaf spring vs coil spring question. They're both springs, but they're made completely differently. A leaf spring is a curved steel beam, usually hot-formed and heat treated. A coil spring is wound from wire. A shop that's great at one can be pretty mediocre at the other.

Same logic applies to struts. A t strut—the T-shaped style used on some trucks and trailers—is typically a stamped and welded assembly. A mando strut has a deep-drawn body with tight wall tolerances. And a 6.7 Cummins exhaust manifold is a high-heat component that's traditionally cast or fabricated from heavy tube—not stamped. A stamping shop shouldn't pretend they can make it as well as a foundry.

The vendor who said "this isn't our strength—here's who does it better" earned my trust for everything else. The one who said "sure, we can do that" cost us $1,400 in rework.

So before you request a quote, decide what process the part actually requires. If their capability list doesn't match, move on.

Step 2: Ask for the Material Cert With the Quote, Not After the PO

If a vendor can't tell you the exact alloy and temper at quote time, they're guessing.

For springs, this is non-negotiable. A coil spring is often SAE 9254 or 5160 wire. A leaf spring is typically 5160 or similar spring steel. Those aren't interchangeable. Honestly, when I started in procurement, I didn't know the difference either—I learned after a 2021 order where the "equivalent" spring wire failed brittle in testing. The supplier had substituted a cheaper grade.

At minimum, request:

• Mill cert / material test report (MTR) for the raw material
• Hardness or tensile results after heat treat
• Coating thickness cert, if plated or coated

If they act annoyed by the request, that's information too.

Step 3: Calculate Total Cost, Not Unit Price

This is where I've seen the most expensive "savings" in my career.

In 2023, I compared quotes for a quarterly order of stamped brackets. Vendor A quoted $2.10 per piece. Vendor B quoted $1.68—about 20% cheaper. I almost went with B until I broke down the total cost. Vendor B charged a $350 setup fee on every order. The boxes weren't labeled to our spec, so I paid a temp worker to sort them. And they charged $200 per part number for PPAP documentation that Vendor A included.

The "cheap" option ended up costing more than the "expensive" one by roughly $0.50 per piece once everything was counted. I might be misremembering the exact setup fee—it was two years ago—but the lesson stuck.

I built a TCO spreadsheet after getting burned on hidden fees twice. Every quote goes into it: piece price, tooling, shipping, MOQ, documentation fees, expected rework rate. Use something like it.

Step 4: Ask About Secondary Operations—This Is the One Everyone Skips

I never asked about this when I started, and it bit me hardest.

A metal part isn't just the stamping or machining. What happens after? Heat treat? Plating? Powder coat? Welding? Here's a real example: we ordered a batch of mando struts that looked perfect in the photos. The one-line quote said "welded assembly," so I assumed brackets were included. They weren't. The bare struts showed up without anything welded on, and the shop we found at the last minute charged rush rates. We saved $0.00 on the price and paid an extra $2,100 in welding and logistics.

When a quote comes in, ask directly:

• What's included vs. what's extra? (welding, assembly, fasteners)
• What finish or coating is standard?
• Is heat treat in-house or outsourced?
• Are there minimums for secondary ops?

If a line item says "misc." or "processing," ask what it means. I'd rather read a quote with 20 line items than one with 4.

Step 5: Verify Quality Documentation Before the PO

I used to treat quality paperwork as a nice-to-have. Then a batch of exhaust manifold flanges arrived with no material test report, and our customer's engineering team rejected the whole lot because we couldn't verify the grade.

I knew I should have requested that documentation in writing. But we'd worked with that supplier for years, and I thought "what are the odds?" The odds caught up with me. The reorder cost us an extra week and a half of lead time.

Before signing a PO, confirm:

• Inspection report format—what do they measure, and how often?
• PPAP or certificate of conformance availability
• Quality certifications—IATF 16949 is the automotive benchmark; ISO 9001 is the baseline

Step 6: Order a Pilot Batch and Measure It Yourself

Even with a clean quote and certs, run a small pilot batch for any new part or supplier.

Order 10-20 pieces if practical. Put them on your customer's fixture or your own bench. Check critical dimensions. For a t strut, check the weld locations. For a spring, check free length and coil gap. Don't just trust the paperwork—measure a few yourself.

A pilot batch caught a miscommunication on a leaf spring order last year. The drawing specified a certain arc height; the supplier had formed to a slightly different one. A 12-piece pilot caught it before a 500-piece order didn't. That was probably a $4,000 mistake avoided.

What Usually Goes Wrong

A few closing notes, all from actual POs:

The cheapest quote wins, then stops being cheap. Saved $40 on a spring order by going with the budget vendor. The shorter fatigue life meant we handled replacement claims under warranty. Net loss dwarfed the savings.

Verbal agreements don't exist. If it's not in the RFQ, quote, or PO, it's not real. I say this as someone who generally trusts suppliers—but I trust written confirmations more.

A good shop knows its limits. This checklist worked for us, but our context is specific: we're a distributor with predictable order patterns. If you're an OEM with constant engineering changes, your calculus might be different. And if a mando shop fits your parts, great—but only if your parts match their processes. I'd rather work with a specialist who knows their limits than a generalist who overpromises.

Bottom line: it's basically six questions—right process, right material, total cost, secondary ops, quality docs, pilot batch. Every time I've skipped one, it's cost me money. Every time I've run the full list, it's been boring and smooth. Boring is good.