SANAA
UREMBO NA USTAWI
UJANJA
UTAMADUNI NA HISTORIA
BURUDANI
MAZINGIRA
CHAKULA NA VINYWAJI
UHANDISI WA KINYUME
SAYANSI
MICHEZO
TEKNOLOJIA
VAZI
Convex and Concave Lenses Ground as a Pair
Rub one glass disc over another with wet grit and both change shape: the one on top goes hollow, the one beneath goes domed, and they stay a perfect fit. Grind both faces of a pair this way and the bottom disc becomes a double-convex lens, the top one a double-concave lens of the same curve. Longer work gives deeper curves and shorter focal lengths.
The picture: a double-convex lens held at arm's length shows the scene small and upside down.
Juu
Several days per pair
Maagizo
1
1
Cut two discs
Cut two discs
Score two equal circles on the glass sheet, snap them out and nibble the edges round with grozing pliers. Fix a short wooden handle to the back of each with warm pitch.
Vifaa kwa hatua hii:
Bamba la kioo1 kipande
Gundi ya Lami ya Msonobari20 g
Utepe wa mbao gumu1 kipandeZana zinazohitajika:
Kikata kioo
Koleo la kumeguka kioo
Miwani ya usalama2
2
Rough grind the first faces
Rough grind the first faces
Lay one disc face up on a firm table, wet it and sprinkle coarse grit. Push the other disc over it, face down, in short strokes, turning both a little all the time. The top one becomes concave, the bottom convex. Rinse and recharge as the grit wears.
Vifaa kwa hatua hii:
Maji2 litaZana zinazohitajika:
Rula
Chembechembe za kabidi ya silikoni3
3
Check the curve
Check the curve
Lay a ruler across the hollow disc and measure the depth at the centre with the caliper. Keep the top disc on top to deepen the curve; swap them to flatten it.
Zana zinazohitajika:
Rula
Kipima-unene cha dijitali cha inchi 64
4
Fine grind and polish
Fine grind and polish
Go through finer grits, washing everything clean between grits. Polish each face on a pitch lap pressed to the other disc's curve, with tin oxide (putty powder) and water, until clear.
Vifaa kwa hatua hii:
Oksidi ya bati (oksidi ya stani)30 gGundi ya Lami ya Msonobari100 gZana zinazohitajika:
Chembechembe za kabidi ya silikoni5
5
Turn them over, do the second faces
Turn them over, do the second faces
Move the handles to the finished faces and grind the other sides the same way, the same disc on top, to the same depth. The bottom disc is now a double-convex lens, the top one double-concave.
Vifaa kwa hatua hii:
Oksidi ya bati (oksidi ya stani)20 gZana zinazohitajika:
Kipima-unene cha dijitali cha inchi 6Chembechembe za kabidi ya silikoni6
6
Find the focal length
Find the focal length
Hold the convex lens in sunlight over paper and move it until the spot is smallest; that distance is its focal length. Grind more pairs to different depths for a set of focal lengths.
Zana zinazohitajika:
Rula7
7
Focal length from the curve
Focal length from the curve
Inapakia daftari la Jupyter…
8
8
Limits
Limits
Which disc goes hollow is the mirror makers' rule (Sky & Telescope, Stellafane); the lens formula is from Wikipedia. Window glass is not optical glass: expect some colour fringes and bubbles.
Vifaa
5- 1 kipandeKishikilia Nafasi
- Kishikilia Nafasi
- 1 kipandeKishikilia Nafasi
- 2 litaKishikilia Nafasi
- Kishikilia Nafasi
Mchoro huu unatengeneza
Blueprint zinazohusiana
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CC0 Umma Wote
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Saidia Mtengenezaji kwa kununua bidhaa kupitia Mchoro wao ambapo wanapata Kamisheni ya Mtengenezaji iliyowekwa na Wachuuzi, au unda marudio mapya ya Mchoro huu na uiunganishe kama kiungo katika Mchoro wako kuchangia mapato.