Shims & Shim Stocks

Shims & Shim Stock

A shim is a thin, precision-thickness piece of material used to fill a gap, take up clearance, or fine-tune the fit between two mating surfaces. Pack enough shims together (or peel back a single thicker one) and you can dial in an exact dimension that no single off-the-shelf part will give you. AIMS Industrial stocks shim stock and pre-cut shims from Precision Brand and Champion — steel, stainless steel and brass, in roll, flat sheet and slotted formats, plus Champion's automotive front-end alignment shim kits. Whether you're setting bearing preload, correcting a soft-foot on a pump, or adjusting camber on a front axle, there's a shim format here for the job. If you're weighing up which one to choose, our Industrial Shim Guide is a good place to start.

Shim Stock & Shim Types — Quick Reference

Choosing the right shim

Material

• Carbon steel — the everyday workshop choice. Cost-effective, easy to cut with tin snips or shears, and magnetic (handy for holding it in place while you work).
• Stainless steel — worth the extra cost anywhere corrosion is a factor: outdoor plant, washdown areas, marine and food-processing environments. It also holds its thickness over time better than plain steel, which matters on a permanent alignment job.
• Brass — non-magnetic and non-sparking, so it's the pick for electrical assemblies, instrument work, and anywhere a ferrous shim could interfere with a magnetic field or pose a spark risk in a hazardous area.

Thickness

Measure the actual gap first — a feeler gauge is the right tool for this — then build the shim stack to match. A practical range to keep on hand runs from around 0.025 mm up through the coarser single-thickness stock, combining a few sheets to hit the number you need. Keep stacks to a handful of shims where you can; too many thin layers in one stack gets unstable under vibration.

Format — roll, sheet or slotted

• Roll stock lets you cut whatever shape and size the job calls for, using tin snips or a shim cutter — the right call whenever the shim isn't a standard rectangle.
• Flat sheet and 150 x 150 mm pre-cut sheet save time when the shape is straightforward and you just need to stack to thickness.
• Slotted shims have a slot cut in from one edge so they can be slid into place around a bolt or shaft without dismantling the assembly — quicker for re-alignment work, though a full (unslotted) shim holds its position better long-term.
• Front alignment shim kits are a different application again — see below.

Common applications

Machinery alignment and levelling

Shims go under motor and pump feet to correct a soft-foot condition — where one mounting foot doesn't sit flush on the base and distorts the housing once the bolts are tightened. Left uncorrected, soft-foot throws out shaft alignment and shortens the life of the coupling and bearings. The fix is to shim the low foot until the housing sits flush without bolt-induced distortion, then check the result with a dial indicator or laser alignment tool rather than assuming the job is done once the shims are in.

The same stock is used for gearbox and coupling alignment, bearing preload adjustment, clearance setting in valve bodies, and general gap-filling in structural connections.

Automotive front-end alignment

Champion's front alignment shim kits are a separate line, aimed at adjusting camber and caster on vehicle front suspension — the classic mechanical workshop task of packing shims behind a control arm or strut mount to bring wheel geometry back into spec. The CA106 and CA107 kits give you an assortment of pieces in one box so you're not caught short on the size you need; the FAS zinc-plated shim is a straightforward single-thickness option for a quick job.

Handling and installation tips

• Always measure the gap with a feeler gauge before selecting shim thickness — guessing wastes stock and time.
• Cut roll stock with tin snips, aviation shears or a sharp knife for thinner material; for thicker steel, a guillotine or punch gives a cleaner edge.
• Deburr every cut edge before fitting — a sharp burr can cut your hand or stop the shim sitting flush against the mating face.
• Build a stack from the largest shim at the bottom up to the smallest on top, and keep the total number of pieces in one stack to a minimum for stability.
• On rotating equipment, re-check alignment with a dial indicator or laser tool after the shims go in — don't assume the number on the shim is the number you actually achieved.

Brands stocked at AIMS

Precision Brand

Precision Brand supplies our roll shim stock (steel, stainless and brass, imperial widths), flat sheet assortments (steel, stainless and brass, 6 x 12"), and stainless steel slotted shims in both metric and imperial sizing — including an assorted-thickness slotted shim set. This is the range to reach for when you need to cut a custom shape, or want a slotted shim that slides in without pulling the bolt.

Champion

Champion is our source for 150 x 150 mm pre-cut sheet shims in steel, stainless and brass (sold in multi-piece packs), 60 mm wide roll assortment kits in steel and brass, single-thickness steel and brass roll and sheet stock, and the front alignment shim kits covered above. Champion makes up the larger share of this range at AIMS.

Companion ranges at AIMS

Shims sit within our broader raw materials range. Measure the gap first with a feeler gauge, then shim it. For the rotating equipment shims are most often used to align, see couplings and bearings & power transmission. For precision keyway stock in the same gauge family, see key steel, and for sealing flat joints alongside a shim stack, see gaskets. You can also shop by brand: Precision Brand and Champion.

Can't find the exact thickness, material or format you need? Call (02) 9773 0122 or contact our team — we can source outside what's shown here within standard lead times.

Frequently Asked Questions

What's the difference between steel, stainless and brass shim stock?

Carbon steel is the everyday workshop choice — cost-effective, easy to cut, and magnetic enough to hold in place while you work. Stainless steel is the pick for corrosion resistance, in outdoor, washdown, marine or food-processing environments, and it holds its thickness better over time on a permanent installation. Brass is non-magnetic and non-sparking, used in electrical and instrument assemblies and anywhere a ferrous shim isn't wanted.

Should I use a slotted shim or a full shim?

Slotted shims slide in past a partially loosened bolt without dismantling the assembly — quicker for adjustment and re-alignment jobs. Full shims need the bolt removed to fit but sit more securely and are less prone to walking under vibration, so they're the better choice for a permanent installation.

What thicknesses of shim stock should I keep on hand?

A general workshop assortment that spans fine thicknesses (down around 0.025 mm) through to heavier single-thickness stock covers most alignment and levelling jobs. Precision Brand's assorted-thickness sheet and slotted shim packs, and Champion's sheet and roll assortment kits, are built for exactly this — one pack gives you a spread of thicknesses instead of buying single sizes as you go.

Can shim stock be cut with hand tools?

Yes. Tin snips, aviation shears or a sharp knife will cut brass and thinner steel cleanly. For thicker steel shim stock, a guillotine or punch gives a cleaner edge with less distortion. Always deburr the cut edge before fitting — a burr can cut your hand or stop the shim sitting flush.

How many shims should I stack in one spot?

Build the stack from the largest shim at the bottom (taking most of the gap) up to the smallest on top for the fine adjustment. Keep the total number of pieces to a minimum — a tall stack of many thin shims is less stable and more likely to walk under vibration than a shorter stack of fewer, thicker pieces.

What is a soft-foot condition and how do shims fix it?

Soft-foot is where one or more of a machine's mounting feet doesn't sit flush on its base — the foot floats when the bolt is loose but distorts the machine housing once the bolt is tightened. It throws out shaft alignment and accelerates bearing and coupling wear. It's picked up by loosening each mounting bolt in turn and checking for movement with a dial indicator, and corrected by shimming the low foot until the housing sits flush with the bolt tightened.

What are Champion's front alignment shim kits used for?

They're an automotive product, not a machinery-alignment one — used to adjust camber and caster on vehicle front suspension by packing shims behind a control arm or strut mount. The CA106 and CA107 kits bundle an assortment of pieces in one box so a workshop has a spread of sizes on hand; the FAS zinc-plated shim is a single-thickness option for a straightforward job.

Do I need to check alignment again after fitting shims?

Yes. On motors, pumps, compressors and other rotating equipment, always verify the result with a dial indicator or laser alignment tool once the shims are fitted — installing a shim doesn't guarantee the alignment is correct, and the only way to know is to measure it.

Roll, sheet or pre-cut — which format should I buy?

Roll stock is the right call when you need a custom shape or size, cut on-site with tin snips or a shim cutter. Flat sheet and pre-cut 150 x 150 mm sheets suit straightforward rectangular shims where you're stacking to a thickness rather than cutting a shape. Slotted shims are the format to reach for when the shim needs to go in around a bolt or shaft without removing it.

What imperial-to-metric shim thickness conversions are useful to know?

0.001" = 0.0254 mm, 0.002" = 0.05 mm, 0.005" = 0.127 mm, 0.010" = 0.254 mm, 0.020" = 0.508 mm. Precision Brand's imperial roll stock is marked in thousandths of an inch; if you're working to a metric spec, convert to the nearest available size — the small rounding difference is normally well within alignment tolerance.