3 sewing
needle. We Show at Fig. 12 a view of the point _A'_, Fig. 11, enlarged,
and the steel tube we have just drilled out attached at _C_. About the
best way to attach _C_ is to solder. After the tube _C_ is attached a
hole is drilled through _A'_ at _d_, and the thumb-screw _d_ inserted.
This thumb-screw should be of steel, and hardened and tempered. The use
of this screw is to clamp the needle point. With such a device as the
tube _C_ and set-screw _d_, a No. 3 needle is used for a point; but for
drawings on paper a turned point, as shown at Fig 13, is to be
preferred. Such points can be made from a No. 3 needle after softening
enough to be turned so as to form the point _c_. This point at the
shoulder _f_ should be about 12/1000 of an inch, or the size of a
fourth-wheel pivot to an eighteen size movement.
[Illustration: Fig. 11]
[Illustration: Fig. 12]
[Illustration: Fig. 13]
[Illustration: Fig. 14]
The idea is, when drawing on paper the point _c_ enters the paper.
Pages:
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38