Granite Parallel Straight Edge 00 Grade 500 x 100 x 40mm - Flat Ruler
Solid black granite flat bar, grade 00, for checking flatness and parallelism and for use as a straight edge on machine tables.
Granite parallel straight edge - 500 x 100 x 40 mm
A solid black granite parallel straight edge, 500 mm x 100 mm x 40 mm, for inspection and machine setup work. Granite parallel straight edge (flat ruler) with two through-holes, one near each end.
Check flatness by laying the bar on the surface under test and looking for light, or by sweeping a dial indicator along the top face. For parallelism, a pair of these bars on a surface plate gives you two known-flat references at a fixed separation. The 500 mm length suits a machine table or a large fabricated part; the 100 mm width keeps the bar stiff enough that its own weight does not bow it in normal handling.
Specification
- Type: Granite parallel straight edge (flat ruler)
- Size: 500 x 100 x 40 mm (length x width x thickness)
- Material: black natural granite, fine grained, lapped working faces
- Grade: 00 (supplier stated)
- Stated accuracy: within 0.005 mm on the working faces (supplier stated, not certificate-verified)
- Working faces: ground working faces along the length of the bar
- Handling: two through-holes, one near each end
- Packaging: wooden case (supplier stated)
- Lead time: 15 working days
What grade 00 actually means
The supplier states grade 00 with accuracy within 0.005 mm on the working faces. That figure comes from the supplier's own specification card, not from a calibration certificate - we have not verified it and we do not include a certificate with the item. Treat it as the supplier's claim, and if you need a documented accuracy for acceptance testing or customer sign-off, have it calibrated on arrival. We would rather say that plainly than print a tolerance we cannot stand behind.
Choosing the right size
Take the shorter bar where it is going to be lifted on and off a machine all day, and the longer one where it has to span a table or a large workpiece. Granite is roughly three times the density of aluminium, so a 500 mm bar is genuinely heavy - plan the lift and use the handling holes.
Handling and care
Granite is hard and stable, but it chips rather than dents. Do not let it slide across a machine table with swarf under it, and never lift it by the blade - use the handling holes. Keep it in its case when it is not in use. Wipe the faces with a clean cloth before a check; a single chip of swarf under the face is bigger than the tolerance you are trying to measure.
What is and is not supplied
One granite parallel straight edge, 500 x 100 x 40 mm, in a wooden case. No calibration certificate or inspection report is supplied, and no stand or surface plate is included. The tolerance is the supplier's stated figure only.
Photographs
The two photographs show a parallel straight edge of this type from the same supplier range. They are representative of the product - the unit pictured is not the exact size listed here, and the size supplied is the size in the title. Granite is a natural material, so the colour and speckle of the stone will vary slightly from the photographs.
