Shims & Shim Stock Raw Materials: what Claude and GPT would buy

Two AI models chose on their own, with no web access. Nobody tested these products: this is what each one says, and how to check it.

Claude and GPT choose the same brand, Precision Brand

In Industrial & Scientific, Claude and GPT choose the same brand in 52 of 107 categories.

Claude Opus 5.5 · October 28, 2026

Precision Brand (brand)

Precision Brand is the long-standing name in US shim stock, with steel, stainless and brass flat sheets, rolls and assortments sold with clearly marked thicknesses.

Not for: People who need preformed slotted or round shims for repeated alignment jobs, since cutting every shim from sheet is slow and less accurate.

GPT 6.1 Sol · November 10, 2026

Precision Brand Stainless Steel Shim Stock (line)

Corrosion resistance and a range of thicknesses make it a versatile choice for precision alignment, leveling, and machinery adjustments.

Not for: Electrical insulation or applications requiring compressible shims.

Check before you buy

Alloy match. Use stainless (302/304) where there is moisture or corrosion, low-carbon steel for general machinery, and brass where you need non-sparking or softer contact. The wrong alloy corrodes, galls or reacts galvanically with the parts it sits between.
Thickness marking and tolerance. Each piece or sheet should be marked with its thickness, and the maker should publish the tolerance it holds. Shimming is only useful if the stated thickness is accurate. Unmarked offcuts get mixed up.
Flat sheet vs roll. Choose flat sheets for precision work. Rolls are cheaper but keep some curl. Curl in thin rolled stock can tilt a stack and add error.
Temper. Use full-hard stock for load-bearing stacks and annealed or soft stock where it must conform or be formed. Soft shims compress under load and alignment drifts over time.

Where to find Precision Brand

Penn Tool Co.
MSC Direct
Zoro

Shops seen in search results on November 6, 2026. A shop missing here may sell it too. Nothing was checked by a person.

Brands that matter

Precision Brand: Broad US line of shim stock, assortments and precut shims.
Artus: Specialist shim maker covering stock, laminated and precut shapes.
Maudlin Products: Known mainly for precut stainless slotted shims for machinery alignment.
Lyon Industries: Precut slotted shim kits for motor and pump alignment.

What to avoid

Unbranded assortments that do not mark the thickness on each sheet.
Thin plastic shim stock in hot or heavily loaded joints.
Plain carbon steel shims in wet or outdoor installations.

Questions

Can I stack several thin shims instead of one thick one?

Yes, but use as few pieces as you can. Every layer adds compressibility and error, so combine the thickest available shims first.

Shim Discs

Shim discs are round shims sold as solid blanks. Choose them the same way as the parent's shim stock, by matching alloy, temper and marked thickness to the joint.

Shim Stock

This is the parent decision. Precision Brand flat stock in the alloy your application needs, with each sheet's thickness marked, is the pick.

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