Samvinna
LIST
FEGURÐ OG VELLÍÐAN
HANDVERK
MENNING OG SAGA
SKEMMTUN
UMHVERFI
MATUR OG DRYKKUR
ÖFUGVERKFRÆÐI
VÍSINDI
ÍÞRÓTTIR
TÆKNI
KLÆÐANLEG TÆKNI
Protractor: Plain Circular Brass Protractor with a Centre Bar (Stanley, 1878)
The draughtsman's circular protractor: a flat brass ring divided all round into degrees and half-degrees, its outer edge bevelled thin so a needle point can feel the divisions, with a bar across the middle whose edge runs exactly through the centre from 0° to 180°. Lay the bar on a line, prick off the angle and draw through the point and the centre.
Result: a protractor for setting off and measuring angles on a drawing.
Source: W. F. Stanley, A Descriptive Treatise on Mathematical Drawing Instruments (1878), pp. 227-228. Unknown: sizes and how the circle is divided. Picture: the book's figure.
Miðlungs
Unknown
Leiðbeiningar
1
1
Make the ring and bar
Make the ring and bar
Cut a flat ring of brass (electrum also serves) with a bar across the inner space. Make one side of the bar a true straight line through the centre of the ring, and mark the centre with a short line in the middle of the bar; a small semicircle may be cut out of the bar's edge there to make it easier to set over a point. Bevel the outer edge down very thin. Not given: sizes. Ours: brass sheet.
Efni fyrir þetta skref:
Messingplata1 ring and barNauðsynleg verkfæri:
Plötuklippur
Málmrennibekkur
Óþekkt mál2
2
Divide it
Divide it
Divide the circumference into degrees, subdivided into half-degrees, so that the bar's edge, carried on, reads 0° and 180°, and number the degrees. Not given: how the circle is divided.
Nauðsynleg verkfæri:
Óþekkt mál3
3
Use it
Use it
To set off an angle from a point on a line, lay the bar so it half covers the line, the line reading 0 to 180, with the point in the centre. Prick off the number of degrees at the bevelled edge with a needle point, lift the protractor away, and draw a line through the mark and the point.
Nauðsynleg verkfæri:
Óþekkt málEfni
1- 1 ring and barStaðgengill
Nauðsynleg verkfæri
3- Staðgengill
- Staðgengill
- Staðgengill
Þessi teikning býr til
CC0 opinbert ríki
Þessi teikning er gefin út undir CC0. Þér er frjálst að afrita, breyta, dreifa og nota þetta verk í hvaða tilgangi sem er, án þess að biðja um leyfi.
Studdu smiðinn með því að kaupa vörur í gegnum teikningu hans þar sem hann fær þóknun smiða sem seljendur ákvarða, eða búðu til nýja endurskoðun á þessari teikningu og tengdu hana sem tengingu í þinni eigin teikningu til að deila tekjum.