Spherometer Three-leg base
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Product Code : SCL-AM-12114
Spherometer Three-leg base (SKU SCL-AM-12114) is a micrometer-screw instrument on a triangular brass frame with three pointed steel legs, used to find the radius of curvature of lenses and other spherical surfaces and the thickness of thin plates. With a least count of 0.01 mm it serves Class 11 and B.Sc. physics practicals. Manufacturing takes place at the Science Lab Supplies factory, Plot 448, HSIIDC Industrial Area, Saha, Ambala, India, which supplies schools, colleges, tender contractors and distributors directly.
Specifications
The table below gives each specification as a separate row. In essence, a cast brass tripod frame carries three hardened steel legs and a central hardened steel screw of 1.0 mm pitch, read on a vertical millimetre scale and a 100-division circular disc, giving 0.01 mm resolution.
| Specification | Value |
|---|---|
| SKU | SCL-AM-12114 |
| Frame | Triangular frame of high-grade cast brass |
| Legs | Three fixed legs with pointed tips forming an equilateral triangle |
| Screw and leg material | Hardened tool steel |
| Screw pitch | 1.0 mm (nominal) |
| Circular scale | 100 equal divisions |
| Least count | 0.01 mm |
| Vertical scale range | 10–0–10 mm or 0–20 mm |
| Reference plate | Optically flat glass plate for zero setting |
| Storage | Fitted wooden or high-density plastic case |
| Documentation | Instruction guide with evaluation formulas |
| Manufacturer | Science Lab Supplies, Saha, Ambala, Haryana |
| Country of origin | India |
Applications and Experiments for the Spherometer
The three legs define a reference circle, and the central screw measures how far a curved surface rises or falls inside it (the sagitta, h). From h and the mean leg spacing, l, the radius follows from R = l²/6h + h/2, a standard measurement in physics lab equipment in India for school and college courses.
- Class 11 physics: radius of curvature of a convex surface such as the Convex Lens 50mm, or of a concave surface.
- Measuring the thickness of thin glass slides, coverslips and metal foils.
- Finding l by pressing the legs onto paper and measuring between the marks with a Vernier Caliper.
- B.Sc. optics: supporting lens-maker formula and focal-length work.
Find the zero error on the glass plate first. Turn the screw gently and stop at contact; forcing it can blunt the tips or crack a sample. Oil the thread lightly every six months.
Standard Scope of Supply
The set includes the three-leg spherometer, an optically flat glass plate for zero-point reference, a fitted wooden or high-density plastic storage case, and an instruction guide with the evaluation formulas. Lenses and other test samples are not included and can be quoted alongside.
Packing, MOQ and Lead Time
Enquiries are welcome for a single spherometer or for a full set for every practical bench. Science Lab Supplies replies with packing, delivery time and price for the stated quantity, and lenses, calipers or micrometers for the same practicals can be added to that quotation.
Science Lab Supplies, which has an Importer-Exporter Code, can ship to buyers in South Africa, Qatar, Sri Lanka, Vietnam, Malaysia and Peru. Get in touch through the contact page, build a list in the enquiry cart, or open the lab tender page for tender-based purchases.
Frequently Asked Questions
What is the least count of the Spherometer Three-leg base?
The least count is 0.01 mm: the 1.0 mm pitch of the central screw divided by the 100 equal divisions on the circular disc scale.
Why does a spherometer have three legs?
Three points always rest steadily on any flat or curved surface, so the legs give a stable reference circle against which the central screw measures the rise or fall of the surface.
Can it measure both convex and concave surfaces?
Yes. The central screw travels above and below the plane of the leg tips, so it can measure the apex of a convex surface or the depth of a concave one with the same precision.
Is Science Lab Supplies the manufacturer or a trader?
Science Lab Supplies makes the spherometer in its own Saha, Ambala factory in India. Because the quotation is issued by the manufacturer, there is no trading company adding a layer between the factory and the buyer.
Related Measuring and Optics Apparatus
These instruments from the physics, Applied Mechanics and Light and Optics ranges cover fine length measurement and the lenses most often measured, so a spherometer practical and its companion optics experiments can be equipped and quoted together for the laboratory.
- Spherometer — brass table with stainless steel legs, 10–0–10 mm scale and 40 mm, 100-division dial.
- Electronic Digital Vernier Caliper — 0–150 mm digital caliper with 0.01 mm resolution.
- Micrometer — 0–25 x 0.01 mm micrometer with ratchet top, supplied in a case.
- Digital Micrometer — 0–25 mm, 0.01 mm resolution, with ratchet stop.
- Glass Lens Demonstration — six 38 mm lens types in a foam-lined wooden box.
- Concave Optics Experiment Lens — crown glass diverging lens for virtual-image work.
- Newton's Ring Apparatus — plano-convex lens on a flat glass plate with three thumbscrews.
Browse the full Applied Mechanics range, the Light and Optics range for lenses, or all physics lab equipment.
Last updated: 9 October 2026
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