- Order shims by thickness in millimetres, not gauge — gauge systems differ by up to 5%.
- SS 304 is the standard shim grade; use 316 for corrosive sites and 410 when a magnetic or harder shim is needed.
- A 1 m² SS 304 shim weighs 7.93 kg per mm of thickness, so 0.1 mm weighs about 0.79 kg/m².
- Measure shims under 0.3 mm with a micrometer, not a vernier caliper.
A shim is a thin piece of metal placed between two parts to adjust a gap, level a machine or take up wear. Stainless steel is the usual choice because it does not rust, keeps its thickness under load and can be cut cleanly with shears. Thin SS coils and shims are a speciality at Sagar Sales Corporation, so this guide collects the questions our customers ask most: which thickness, which grade, what tolerance, and how to order.
Stainless steel shim thickness chart
Thin stainless is sold by thickness in millimetres. Gauge numbers are still used in older drawings, so both are shown. Weights are for SS 304 (density 7.93 g/cm³); 316 is about 1% heavier.
| Thickness (mm) | Thickness (inch) | Nearest gauge | Weight (kg/m²) | Typical use |
|---|---|---|---|---|
| 0.05 | 0.002 | — | 0.40 | Fine alignment, feeler shims, electronics |
| 0.10 | 0.004 | 38 SWG | 0.79 | Precision machine alignment, laminated shim packs |
| 0.15 | 0.006 | — | 1.19 | Pump and motor alignment |
| 0.20 | 0.008 | 34 SWG | 1.59 | Bearing housings, coupling alignment |
| 0.25 | 0.010 | 32 SWG | 1.98 | General maintenance shims |
| 0.30 | 0.012 | 30 SWG | 2.38 | Gaskets, spacers |
| 0.40 | 0.016 | 28 SWG | 3.17 | Die and mould packing |
| 0.50 | 0.020 | 26 SWG | 3.97 | Levelling plates, spacers |
| 0.60 | 0.024 | 24 SWG | 4.76 | Structural packing |
| 0.80 | 0.031 | 22 SWG | 6.34 | Heavy spacers |
| 1.00 | 0.039 | 20 SWG | 7.93 | Thick shims, light sheet work |
Above 1 mm the material is usually described as sheet or strip rather than shim. For weights of thicker material see the size and weight charts.
How shim thickness is specified
Always order in millimetres, not gauge. Gauge systems differ (SWG, BWG, US standard) and the same number can mean two different thicknesses. If a drawing says "30 gauge", confirm whether it means 0.30 mm or 30 SWG (0.315 mm) before ordering; the two differ by 5%, which matters for a precision shim pack.
Thickness tolerance
Cold rolled stainless strip is made to the tolerances of standards such as ASTM A480 and EN ISO 9445. For thin material the tolerance is small in absolute terms but large as a percentage, so it pays to know what to expect.
| Nominal thickness | Typical tolerance (precision strip) | As a percentage |
|---|---|---|
| 0.05 mm | ± 0.005 mm | ± 10% |
| 0.10 mm | ± 0.008 mm | ± 8% |
| 0.20 mm | ± 0.012 mm | ± 6% |
| 0.50 mm | ± 0.025 mm | ± 5% |
| 1.00 mm | ± 0.04 mm | ± 4% |
These are typical values; the exact tolerance depends on the mill and the width. If your application needs a tighter tolerance, say so when you ask for a quote so we can offer precision-rolled strip, and always measure with a micrometer rather than a vernier for anything under 0.3 mm.
Which grade of stainless steel for shims?
- SS 304 is the standard choice: non-magnetic, corrosion resistant and widely stocked in all thin gauges. Use it unless you have a reason not to.
- SS 316 / 316L for shims in chemical plants, coastal sites and anywhere chlorides are present. It costs more, but a corroded shim changes thickness and defeats its purpose.
- SS 410 / 420 when a magnetic or hardenable shim is required, for example where shims are held by magnets during assembly, or where a harder surface resists indentation.
- SS 301 full hard for spring shims and clips that must flex and return.
- SS 202 for low-cost indoor shims where corrosion is not a concern.
Full grade details are on our grades pages, and the chemical composition chart compares them side by side.
Temper: soft or hard?
Thin stainless is supplied annealed (soft, easy to cut and bend) or in a hard temper (quarter, half or full hard, obtained by cold rolling). Shims that are cut to shape and left flat are normally annealed. Shims that must spring, or resist being crushed under bolt load, are ordered in a hard temper. Tell us the application and we will recommend the temper.
Coil, strip or sheet?
| Form | Best for | Notes |
|---|---|---|
| Shim coil | Workshops that cut their own shims as needed | Most economical per kg; widths from a few mm to 1250 mm |
| Slit strip | Standard shim widths, gasket makers, OEMs | Slit to your width, so no trimming |
| Cut sheets | Toolrooms and maintenance stores | Flat packs in standard sizes such as 300 × 300 mm or 1000 × 2000 mm |
| Cut-to-size pieces | Fixed shim sizes in volume | Sheared to your dimensions |
See our shim and shim coil page and slit coil page for what is available.
How to measure a shim correctly
- Use a micrometer with a ratchet stop, not a vernier caliper. A caliper reading on 0.1 mm material can easily be out by 20%.
- Clean the shim and the anvils; a speck of dust is 0.01 mm.
- Measure at three points and use the average. Thin coil is thicker in the centre of the width than at the edges.
- For shim packs, measure the stack, not each leaf, and allow a small amount for burrs between layers.
Buying tips
- Order by thickness in mm, grade, temper, width and quantity in kg or metres. "Shim 0.2 mm 304 annealed, 100 mm wide, 20 kg" is a complete order.
- Ask for the mill test certificate; it shows the actual thickness, chemistry and hardness of the coil.
- Thin coil is sold by weight but used by length. Use the weight column above: 0.1 mm × 100 mm wide strip weighs 0.079 kg per metre, so 20 kg is about 250 m.
- Keep shim stock dry and interleaved with paper. Even stainless can stain if stored damp against carbon steel.
Need shim coil, strip or sheets? Send the thickness, grade, width and quantity on our enquiry form or WhatsApp and we will quote the current rate, with delivery anywhere in India.