Choosing a Granite Inspection Surface Plate: Application Fit and Specification Checks

1. Start with your application

The product listing says the plate is intended for:

• Precision gauging and inspection
• Layout and marking
• Industrial production and laboratory measurement work

The listing also says granite surface plates are preferred by laboratories, engineering industries and workshops. If your work is mainly spotting, tool marking or general layout in a heavy workshop, compare this plate with the cast iron option in Section 6 before you decide.

2. Material properties to review

The listing describes the stone as black granite. Its main minerals are pyroxene and plagioclase, with small amounts of olivine, biotite and magnetite. According to the supplier, natural aging gives the stone a uniform texture, good stability and high hardness, and it can hold accuracy under heavy loads. Because the granite has aged for a long time, the listing says it no longer has internal stress. The supplier states that this is why its accuracy is much higher than that of cast iron platforms. The listing also highlights that granite plates do not rust.

The published physical parameters are:

Some units in the listing are unusual. For example, compressive strength is given as "kg/m m²" and water absorption has no unit. If these values go into your acceptance criteria, ask the supplier for the exact units and test basis.

3. Size and flatness

According to the listing, the plates are machined and then hand-ground in a constant-temperature chamber. The published size ranges are 200×200 mm to 3000×5000 mm in one part of the listing and 1000×750 mm to 3000×4000 mm in another. Custom sizes are also offered. The supplier's parameter table lists flatness in μm by plate size. Some examples:

The table header shows precision grade columns 0 and 1. Larger sizes have two values, and smaller sizes have only one. Before you order, confirm which precision grade each flatness value applies to at your chosen size.

How to size the plate: pick a working area that fits your largest workpiece plus your gauges and fixtures. Then check the listed flatness for that size. On this table, larger plates have larger flatness values.

4. Precision grade

The listing gives the precision grade as 0–2 in its specification fields. Elsewhere in the description, it mentions accuracy levels 000, 00, 0 and 1. Because the two ranges differ, state the grade you need in your inquiry and ask for written confirmation of the grade and flatness that will be supplied.

5. Surface features, stand and packaging

• Working surface: flat, with tapped holes, T-slots and other options available
• Surface treatment: ground finish
• Working surface hardness: HS70
• Stand: available
• Packaging: plywood box
• Customization: OEM, ODM and OBM support listed
• Brand / model: Storan, model number 1006
• Place of origin: Hebei, China
• Warranty: 1 year

If you need tapped holes or T-slots, send a drawing that shows their positions. Adding features may affect how the surface is finished, so confirm the flatness that will apply once the features are added.

6. When a granite plate may not be the right fit

The same supplier lists a Cast Iron Inspection Surface Plate (model 2011). Its published specifications are:

• Material: HT200-300, QT or steel, heat-treated to relieve internal stresses
• Sizes: 200×200 to 4000×8000 mm, or custom
• Working surface hardness: HB160-240
• Precision grade: 0–3
• Structure: ribbed
• Working temperature: (20±5) ℃

It is described for spotting, tool marking, inspecting workpieces, checking the accuracy of other surfaces, and gauging and layout work. Its listed sizes go beyond the largest granite size. If you need a working area larger than 3000×5000 mm, or you specifically need a cast iron surface for spotting work, review the cast iron plate instead.

If you need a rust-free surface, harder stone and the higher accuracy the supplier attributes to granite, the granite inspection surface plate is the more relevant choice.

7. Lead time, supply and commercial terms

• Lead time: 30 days for a single piece. Lead time for more than one piece is to be negotiated.
• Supply ability: 20,000 pieces per year (as listed)
• Price: not published. Request a quotation for your size, grade and surface features.
• Certifications and calibration documents:

Buyer checklist

1. Application: inspection, gauging, layout or marking
2. Required working area and plate size
3. Precision grade, and the flatness value that applies to it at that size
4. Surface features: plain, tapped holes or T-slots
5. Whether you need a stand
6. Order quantity, so lead time can be confirmed
7. Any documents you need, such as inspection reports or certificates

Send these details to Storaen (Cangzhou) International Trading Co. so the specification and terms can be confirmed for your granite inspection surface plate.