How to Choose Metal Siding for Wholesale, Read Elevator Component Catalogs, and Spec Glass Railings: FAQ from a Quality Compliance Manager

I run quality and brand compliance for a metal products company. My job is to catch problems before they reach customers—roughly 200+ SKUs a year across grating, mesh, perforated panels, elevator components, and railing systems. I've rejected around 12% of first deliveries in 2024, mostly over coating thickness, flatness, and certified mill paperwork.

These are the questions I actually get asked by procurement folks, spec writers, and site supers. Short answers, no fluff.

Q1: Is McNichols just a distributor, or do they make the stuff?

Both, sort of. McNichols carries one of the widest metal product portfolios in North America—grating, wire mesh, perforated panels, cladding, handrail and stair systems, elevator components, structural steel, roofing and siding panels, formwork and scaffold components. Some items come from their own fabricating operations; a lot comes from a network of mills and OEMs. For a buyer, the practical difference is this: you get one PO, one logistics chain, and OEM / private label support if you want your own branding on the packaging.

What that means on the spec side is you need to ask which mill or fab shop is producing your order. Not every line item on a McNichols quote has the same origin. I ask this question every time, and it's saved me at least two rework cycles.

Q2: What should I check on a McNichols steel delivery before I sign the BOL?

Three things, in this order.

First, mill certs. ASTM A36 for structural carbon steel, A572 Gr.50 if you need higher yield, A123 for hot-dip galvanizing. If the heat numbers on the cert don't match the heat numbers stamped on the material, stop. Don't unload.

Second, coating thickness. A123 calls for a minimum average 85 µm (3.4 mils) zinc on material ≥ 1/4" thick, and 45 µm (1.8 mils) on thinner stock. I use a magnetic gauge on 10 random spots per bundle. In early 2024, we caught a batch where half the load read 55–60 µm. Vendor claimed "within industry standard." It wasn't—that spec was for thin gauge, not our 3/8" plate. They redid it at their cost.

Third, flatness on perforated and mesh panels. Run a straightedge. If you see more than 1/4" of bow over 4 feet on a cladding panel, you'll fight it on install. That's a labor cost your GC will bill back to you.

Q3: The elevator components catalog is huge. How do I actually read it?

I knew I should've walked the catalog with our installer before placing the first order, but thought "it's just standard hardware, what could go wrong?" Well, the odds caught up with me. We ordered guide rails and toe guards using catalog part numbers, assuming the load ratings matched our cab weight. Two were for a different car class entirely. That mistake cost us a $14,000 redo and pushed a job by nine days.

Here's the short version I now give new buyers: the McNichols elevator components catalog isn't organized by part number, it's organized by subsystem—car frames, door operators, counterweight guides, buffers, sill and toe guards, safeties. Filter by subsystem first, then by rated load (in kN, not lbs—the catalog is metric), then cross-check against ASME A17.1 requirements for your jurisdiction. If the catalog doesn't list a rated load, call. Don't assume.

This worked for us once I set up the workflow, but our context is mid-volume commercial elevators. If you're doing high-rise traction systems, the calculus changes—you probably want a dedicated vendor rep.

Q4: Glass railing specifications—what's non-negotiable?

Four specs, and I don't flex on any of them.

• Glass type: laminated, not tempered monolithic. Tempered shatters into dice, which is terrible for a fall-protection barrier. Laminated holds together after breakage.
• Interlayer: 1.52 mm PVB minimum, or 1.52 mm SentryGlas for higher post-breakage stiffness. SentryGlas costs about 2.5× more per panel but often lets you reduce glass thickness, so the total can come out close.
• Rated load: per ASTM E2353, glass railing must resist a 200 lb concentrated load at any point on the top rail, and 50 lb per linear foot uniform. If a supplier can't show you the test report, they haven't tested.
• Top rail attachment: base shoe or standoff—either is fine, but the anchorage into the substrate is where most failures happen. Get the structural calc for the embed.

I get why buyers push back on laminated glass—it's more expensive and the lead time is longer. But the liability math on a 4th-floor balcony isn't close.

Q5: How do I choose metal siding for wholesale without getting burned?

Wholesale siding buyers care about three things: panel gauge consistency, paint adhesion, and packing. Not the marketing sheet.

Gauge consistency: a "24 gauge" siding panel can legitimately range from 0.0226" to 0.028" depending on whether the mill uses the old USS standard or the newer ASTM A924. Ask which one. On a 50,000 sq ft order, that difference is real tonnage.

Paint adhesion: ask for the coating system—typically 70% PVDF (Kynar 500 or Hylar 5000) for exterior. Field testing is a simple cross-hatch tape pull per ASTM D3359. I've seen "PVDF-equivalent" coatings fail that test in 10 seconds. To be fair, some cheaper polyester systems are fine for interior liner panels. Just don't spec them on a south-facing wall in Phoenix.

Packing: siding dents in transit. If the quote doesn't include edge protection and interleaving for wholesale volumes, factor in a 3–5% damage rate. I saved $80 per bundle once by skipping the upgrade. Ended up eating $400 per bundle in field rejects.

Q6: One thing nobody asks—but should

Traceability. Every load of McNichols steel, every mesh panel, every elevator bracket should carry a heat lot or batch code that ties back to a mill cert. If it doesn't, you have no path when a warranty claim comes up two years later.

We switched to a scanning protocol in 2022—every SKU gets scanned against its cert on receiving. Turnaround on receiving inspection dropped from about 5 hours to 90 minutes, and our claims rejection rate went up because we finally had data. Reduction in manual data entry errors alone paid for the scanners in eight months. I can only speak to our volume—if you're receiving under 50 SKUs a month, paper logs might still be faster. But the direction the industry is going is clear.

If you're working with McNichols on any of these product lines and something on the cert or the catalog doesn't add up, push back before you unload. It's cheaper for everyone.