Calipers for Measuring

I find vernier style calipers very useful. They can be used to scribe accurate ground glass markings with a sharp pencil. They can measure an aperture. CAREFULLY, don't scratch anything! They can measure images on film, tube sizes, wall and plate thickness, drill sizes and be used to lay out your work for machining. You can find the center of many shapes by trial and error dividing. You can also divide a circle in to different segments. When working with metal or plastic, center punch a starting or center mark from which you can scratch a circle with the opposite sharp point.

I prefer the old vernier style, but the newer dial or digital models work fine. When you get used to one don't change.

Don't use one to measure flange to film depth. They are not accurate enough for this measurement. You need a real depth gauge and polished plate for the film plane.

Calipers also aren't that accurate on small inner diameters.

You can remove internal rings with a cheaper or damaged one. Use a bar to gain leverage. Be careful to not scratch a lens. Two holes in a thin bar can work too.

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