Shim Thickness Calculator
Calculate shim pack thickness, add-or-remove adjustment, two-point taper, and practical shim stock combinations for machine feet, covers, spacers, and tooling setups.
⚙ Shop Presets
Choose a real alignment scenario, then fine-tune the measurements from your feeler gauge, dial indicator, or clearance check.
📏 Shim Measurements
Shim Pack Results
🔧 Selected Material Snapshot
📋 Shim Stock Thickness Reference
| Nominal Stock | Metric Equivalent | Common Use | Stack Note |
|---|---|---|---|
| 0.001 in | 0.025 mm | Final trim | Use sparingly |
| 0.002 in | 0.051 mm | Fine correction | Good for dial moves |
| 0.005 in | 0.127 mm | Light pack | Common feeler step |
| 0.010 in | 0.254 mm | General alignment | Stable base layer |
| 0.020 in | 0.508 mm | Medium lift | Reduces leaf count |
| 0.060 in | 1.524 mm | Heavy correction | Confirm bolt length |
⚒ Material / Spec Comparison Grid
| Material | Crush / Creep | Environment | Typical Applications |
|---|---|---|---|
| Stainless steel | Very low | Wet or chemical | Pumps, motors, outdoor machines |
| Carbon steel | Very low | Dry shop | Machine feet, fixtures, rails |
| Brass | Low | Moderate corrosion | Bearings, covers, soft contact faces |
| Aluminum | Moderate | Light-duty dry areas | Covers, panels, light tooling |
| Plastic laminate | Moderate to high | Electrical isolation | Isolated feet, temporary setup |
| Fiber gasket paper | High | Sealing faces | Caps, covers, oil housings |
📐 Alignment Taper Reference
| Taper Reading | Imperial Meaning | Metric Meaning | Shop Interpretation |
|---|---|---|---|
| 0 to 0.5 thou/in | 0.0005 in per in | 0.5 mm per m | Fine alignment range |
| 0.5 to 1.5 thou/in | Light slope | 0.5 to 1.5 mm/m | Shim one side carefully |
| 1.5 to 3.0 thou/in | Noticeable slope | 1.5 to 3 mm/m | Recheck base condition |
| Over 3.0 thou/in | Large taper | Over 3 mm/m | Inspect bent foot or burrs |
📝 Common Shim Jobs
| Job | Usual Measurement | Useful Stock | Extra Check |
|---|---|---|---|
| Soft foot correction | Feeler gap under loose foot | 0.002 to 0.020 in | Repeat after torque |
| Coupling vertical move | Indicator offset and foot span | 0.005 to 0.060 in | Check front and rear feet |
| Bearing cap clearance | Endplay or plastigage result | 0.001 to 0.010 in | Confirm crush or preload |
| Flange spacer fill | Average face gap | 0.010 in and thicker | Check parallel face gap |
| Fixture plate leveling | Dial sweep over pad span | 0.001 to 0.020 in | Deburr contact pads |
💡 Shim Calculation Tips
Precision alignment involve making sure that the motor and the baseplate are in the correct position to prevent the motor from failing an bearings. Many individuals attempt to align the motor by adding shim to the motors baseplate and the motor’s bolts to even out the motor. However, this is inaccurate because alignment involves more than just the height of the motor.
An individual focusing only on the height may not notice that the motor have a taper. A taper indicates that the motor is not even with the baseplate, and an individual who only even’s the height of the motor will not even out the motor. An individual must choose the right material to use for the shim pack.
How to Align a Motor with Shims
Stainless steel is a common material for shim packs. This is because stainless steel will not rust, and because stainless steel will not rust, it is perfect for use in pumps or for use in outdoor equipment. Carbon steel is an alternative for shim packs.
However, carbon steel will rust if use in a chemical plant. Another alternative would be using a soft material for the shim pack, like brass or aluminum. However, these materials can experience the crush factor.
If an individual torques a bolt, it can compress the soft metal, which will change the height of the shim pack. An individual must account for settling and safety factors. Every time the bolts is tightened with a wrench, the shim pack will settle.
If the shim pack is made out of metal alone, it will not settle much. However, if the shim pack contain a fiber gasket or plastic laminate, it will compress when the bolts are tightened. If an individual calculates the gap in the motor but does not calculate the crush factor, the shim pack will be too thin to provide adequate support for the motor.
A person can use a calculator to calculate each of these factors to ensure the shim pack reaches the proper height for the motor after the bolts are torqued. The structure of the shim pack is also important. An individual should not use many thin sheet of metal to provide the height for the motor.
Too many thin sheets will create a spring. A spring in the shim pack for the motor is bad because a spring will allow the motor to move. A moving motor isnt properly aligned to the baseplate.
Therefore, an individual should use a thick base layer of shims for the motors base and thin sheets on top to allow for even small changes in height. The span between the measurement points can also impact the alignment of the motor. The span is the distance between the two points of measurement between the motor and the baseplate.
The distance between these two points will impact the tilt of the motor if there is a change in the thickness of the shims. A change in the thickness of the shims will cause a large tilt of the motor if placed on a narrow base. However, a small change in the thickness of the shims will cause a small tilt of the motor if placed on a wide base.
By calculating the taper of the motor within the span of the motor, an individual will be able to understand the geometry of the motor. This will prevent the alignment process from creating a problem at one end of the motor if solve at the other end of the motor. An individual must account for environmental factors with the motor.
The motor may be properly aligned when it is cold. However, the motor may not be properly aligned once it reaches its operating temperature. The reason for this is due to the thermal expansion of the metal of which the motor is made.
If the metal expands, it will grow in size. Therefore, an individual should not aim for a zero offset for the motor alignment. Rather, an individual should account for the metal expansion by aiming for an offset that allows for expansion of the metal without crushing the motors bearings.
Using calculations and measuring motor tapers will ultimately allow an individual to tighten and loosen the motor bolts less times. If an individual can calculate the proper shim pack and understand the taper of the motor, they will reach the proper alignment in fewer steps. Furthermore, an individual must use a feeler gauge to ensure the alignment of the motor.
The final torque of the motor will change the position of the motor and shim pack.
