DOI Page / Citation link:
https://doi.org/10.11588/diglit.62828#0114
Prob. XV. Fig. 26.
To draw an Qval of any length and breadth by means of
two bradauls and a chalk line.
The above methods for drawing ovals fuit wTell for fmall
ovals defcribed on paper, or any kind of metallic furface, when
very fmall ovals are wanted to be drawn on wood. But when
ovals of a large fize are wanted, they become inconvenient
on account of their centers. Therefore Cabinet-makers gene-
rally make ufe of a tramel, by which any oval from two to
about four feet may be drawn, both with more difpatch and
accuracy than can be done by any other method. The method,
however, which is here propofed, is not without its advantages,
fince by it an oval may be drawn as large as we pleafe, both
with little trouble and confiderable exadtnefs, provided that
materials fufficiently ftrong and large enough were fubifituted
in place of the bradauls and chalk line.
Operation.—Let B D be the length of the oval, and A s
half the ihort diameter. Take then half of the longed: dia-
meter, and place it from A to a till it touch the line a s exactly
at a, Again, take the length a j and place it on the right hand
at the bradaul; then will the two centers be found in which
the bradauls are to be fixed. Laftly, take a line and put it about
the
To draw an Qval of any length and breadth by means of
two bradauls and a chalk line.
The above methods for drawing ovals fuit wTell for fmall
ovals defcribed on paper, or any kind of metallic furface, when
very fmall ovals are wanted to be drawn on wood. But when
ovals of a large fize are wanted, they become inconvenient
on account of their centers. Therefore Cabinet-makers gene-
rally make ufe of a tramel, by which any oval from two to
about four feet may be drawn, both with more difpatch and
accuracy than can be done by any other method. The method,
however, which is here propofed, is not without its advantages,
fince by it an oval may be drawn as large as we pleafe, both
with little trouble and confiderable exadtnefs, provided that
materials fufficiently ftrong and large enough were fubifituted
in place of the bradauls and chalk line.
Operation.—Let B D be the length of the oval, and A s
half the ihort diameter. Take then half of the longed: dia-
meter, and place it from A to a till it touch the line a s exactly
at a, Again, take the length a j and place it on the right hand
at the bradaul; then will the two centers be found in which
the bradauls are to be fixed. Laftly, take a line and put it about
the